Submarine Attack Course Finder (a.k.a. Is-Was / Banjo)

[Captain Krunch]

Over at the Historic Naval Ships Association Board (http://www.hnsa.org/board/viewtopic.php?t=59), a gentleman by the name of Mike posted pictures of a Submarine Attack Course Finder (Is-Was) from 1943. The story goes that a family member picked it up for him at a gun show for $5. If you look at his photos, you'll see that it looks like it was made yesterday, so I'm betting that Mike has a very rare find.

Being without an Is-Was myself, but wanting one very badly, I did the next best thing and made my own! Using Mike's high-quality photos, I was able to make what I think is a pretty fair recreation of the main side of his Is-Was, using MS PowerPoint as the drawing program. After creating it in Powerpoint, I converted it to Adobe PDF, and am making the file available for download here (http://rapidshare.com/files/19118009/Submarine_Attack_Course_Finder.pdf.html).

Mike said his Is-Was was 7 1/4 inches in diameter, so I made this one that size as well. The first two sheets (The A and B rings) should be printed on heavier card stock, while the second two sheets (The C and Periscope ring) should be printed on transparancies.

I'm halfway done with the second side of the Is-Was, but I'm having problems in figuring out the middle "Bearing in Degrees" ring. The line spacing does not appear to match up with any other standard circular slide rule markings, so I'm not sure if I'll ever be able to complete it. If anyone has any ideas, let me know.

Having played with the Is-Was for a few days now, I think I've figured out how to use it, although there are still a few things about it that bug me. This is what I assume the rings are used for:

A Ring - Represents the submarine, and shows relative bearings
B Ring - Represents the sub's true course/bearing
Periscope Ring - Represents target bearing
C Ring - Represents course and angle on the bow of the enemy vessel

This works for the most part, but there are a few design issues that bother me:

a) I feel that the protrusions on the A Ring are backwards. I always think that the pointy end represents the bow of the sub, and the half-cirlce represents the stern - but if the A Ring is used to represent the sub, then the half-circle is located at the 0-degree marker. This seems counter-intuitive to me.

b) The Periscope Ring should have a more obvious marker to show where AoB is. I know it is 180 degrees from the actual "Periscope" marker, but in the heat of battle, it's easy to forget. I may add a marker to clearly show the AoB.

Despite that, it's going to be a pretty cool toy to use once SH4 arrives. So, please enjoy the Is-Was!

Krunch

[fire-fox]

Very nice find! ill D/L it when i get home from work, any idea if there is a rivers side to the real one and if there is are there any plans for you/any one else to make it?

EDIT: sorry just read the secound half of your post and feal prity thike as you already answerd this Q.

[Mav87th]

Very Cool Krunch - thnx a mill for the work

As for materials - tranperencys wont cut it as you wrote on HNSA (can't answer there as i have no account), but if you make the layer in transparent paper and then laminate it with the thikest lamination you can get (paperstors usualy can do that for you pretty cheep) then i think that will work.

Would it be hard for you to make a version where all the pages (wheels) are all white? I would like to make the colorisation by the use of colored paper (off white etc.)

[Mav87th]

Hmmm in construction it pretty much resembles a Nasmith Director witch was allso a Target Course Finder.

[Captain Krunch]

I agree that transparencies are not the best solution, but at least they're readily available to most people. My mock-up was made out of card stock and transparencies, and it seems to be holding up fairly well. But I like your idea of using clear lamination to give it strength; that's a lot simpler than what I was going to do (Which was make decals and put them on clear styrene sheets).

It's no problem to make a complete black and white one; it'll be a day or two at most.

[Mav87th]

I used the lamination method on all the transparent of Kim's Tools some time back, and it holds out really good, and they are pretty stiff as well.

Im not in a hurry here, so whenever you see fit - im just glad you take the time to make it :up:

[Rykaird]

Over at the Historic Naval Ships Association Board (http://www.hnsa.org/board/viewtopic.php?t=59), a gentleman by the name of Mike posted pictures of a Submarine Attack Course Finder (Is-Was) from 1943. The story goes that a family member picked it up for him at a gun show for $5.

I have seriously got to go to my first gun show. I thought they only had guns - not cool historical sub stuff.

[Captain Krunch]

I've posted an all B&W version of the Is-Was here (http://rapidshare.com/files/19962065/Submarine_Attack_Course_Finder_White.pdf.html). Let me know if there are any problems with it.

[Mav87th]

I've posted an all B&W version of the Is-Was here (http://rapidshare.com/files/19962065/Submarine_Attack_Course_Finder_White.pdf.html). Let me know if there are any problems with it.

File was deleted.
Reason: Deleted by uploader.

Thats what pops up when i click the link 8th march 2200 GMT

BUHUUHUUUuuuuuuuu:help:

[Captain Krunch]

Wow, that's weird, sorry about that. Try this link; it seems to be working for me:

B&W Is-Was (http://rapidshare.com/files/20112558/Submarine_Attack_Course_Finder_-_White.pdf.html)

[Mav87th]

That one worked like a charm - much appreciated :up:

[Hitman]

'm halfway done with the second side of the Is-Was

Has that reverse side been finished yet? Looking forward to printing it:up:

[sqk7744]

Me too, Brilliant printable version may I say, it's great fun and really adds to the immersion! I wonder if there is a store/site that has overstock issue? Sportys.com pilot shop has original E6B's from the 40's, can any skips' out there suggest some Naval ones?

Take a bow Captain Krunch! :up:

[Hitman]

I have already built mine thanks to your template, and it looks and works AWESOME. Finding the AOB has never been that easy since now I can put the wheel HORIZONTALLY in front of me (Instead of vertically, as the monitor display of the PC we are used to) and thus it is much easier to compare with the enemy vessel you are seeing -which despite being also rendered vertically, has "3D" depth-.

a) I feel that the protrusions on the A Ring are backwards. I always think that the pointy end represents the bow of the sub, and the half-cirlce represents the stern - but if the A Ring is used to represent the sub, then the half-circle is located at the 0-degree marker. This seems counter-intuitive to me.

b) The Periscope Ring should have a more obvious marker to show where AoB is. I know it is 180 degrees from the actual "Periscope" marker, but in the heat of battle, it's easy to forget. I may add a marker to clearly show the AoB.


He he I found out why the A scale is reverse pretty quick :p It is meant to be read from the PERISCOPE layer (The transparent one with marks) and not from the own ship overlay of the A disk.

Example: A target is 45º to the right of your bow, and has an AOB of 60º port. You are heading 200º right now. Here's how to set up the wheel:

1.- Move the B ring (True course) until its 200º mark is at the bow of your own ship silhouette in ring A (Matching the 180º mark in the A ring)

2.- Move the Periscope transparent layer to the 45º mark of the A ring. (Here's the reason why it is reversed! To move your scope "right" means in fact moving in the opposite direction the lower part of that wheel, so that the upper shows the target with the correct AOB side)

3.- Last, set the estimated AOB of your target (60º port) in the B ring.

Result: Your target's true course is 105º:smug:, as you can now read in the B ring (True course ring)

[Meridian]

Looking forward to printing and making one of these up, nice job.

I assume Parts "P" & "C" are printed on transparent media?

[Von Hinten]

Looks great! Thanks for making and explaining it. :up:

[OakGroove]

Very nice! Thanks for sharing. :up:

[jmr]

Looking forward to printing and making one of these up, nice job.

I assume Parts "P" & "C" are printed on transparent media?

I think it's just the periscope one that needs to be transparent but it would be nice if someone else can confirm this.

[Hitman]

I only made the scope transparent, the other one can also be made transparent -and in the original it seems to be- but doesn't make any difference at all:smug:

[sqk7744]

Very neat! ~ would someone be so kind as to post another step by step example.

Thanks much!

I've got these wheels down (I think):

-A (relative bearing)

-B (true course / compass heading)

-Periscope Transparency ( if the Periscope marked end with view window goes on the Subs bearing to target) then the 180 (reciprocal) arrow points to AOB right?

[now for the wheel that came off the bus...]

-D The AOB wheel is where I'm getting confused ( I'm pretty good at judging AOB manually into the TDC, but want to use the Neat Wheel.

[sqk7744]

thanks much

[Captain Krunch]

First off, I'm glad to see interest in the Is-Was I made; I hope it helps people enjoy SH 4 even more.

Regarding transparency, the original had both the C and Periscope dials clear, but after your comments, I don't see why the C dial couldn't be printed on paper. But the Periscope dial must be clear so that you can see the values underneath.

The way I believe the wheel works is like this. Prior to a ship sighting, the A and B dials can be pre-set together to your heading, with the "0" degrees mark of the A dial representing the front of the ship, and the B dial showing true heading of the ship, by placing the heading value at the A dial "0" degrees mark. So if you're heading due east (90 degrees), then the A dial "0" degrees mark = the B dial "90" degrees mark.

So let's say you're traveling due east, 90 degrees. Then suddenly, you get a ship contact (Via sonar, periscope, etc. It doesn't matter). "Sir, new contact, 300 degrees relative!" What I do is I move the Periscope dial so that the triangle is over the A dial "300" degree mark. This is also equal to a B dial value of "30" degrees. The B dial can now tell you what true heading to take if you want to head straight for the contact. "Helm, make new course 30 degrees".

But let's pretend you don't change course. Ok, now the last bit of the puzzle is Angle on the Bow. You have two ways to use this. First, if you can determine the true course of the contact via plotting, you can input the contact's heading to determine AoB. "Sir, contact heading is plotted out to be 330 degrees!" You do not move the A, B, and Periscope dials; you move the C dial until the "0" degrees mark of the C dial is pointing to the "300" degrees mark of the B dial. When you do this, you look at the Periscope dial marker 180 degrees opposite the Periscope triangle. This marker points at "120", on the left side of the C dial ship, so this tells you that the contact AoB is 120 degrees port.

On the other hand, let's say you visually estimate the AoB, and decide it to be 100 degrees port. You move the C dial "100" port value so that it matches up with the Periscope dial marker that is 180 degrees opposite the triangle. When this is done, you can then determine via the B dial that the contact's heading is 310 degrees true.

Once this is done, you decide to make a direction change, and head straight for him. You do not move the B, C, or Periscope dial; instead, you just move the A dial so that the "0" value matches up with the Periscope marker that you had already preset above.

That's probably a way-too-verbose answer, but I hope it helps. I suggest playing around with it for a while, and eventually you'll get the hang of it. Good luck!

[WernerSobe]

im not sure if i get it right...

You can find the course of your target with that? Why anyway? the more interestning thing to find out would be the AOB.

[WernerSobe]

btw ive seen pictures of a wiz wheel as it was used in german submarines. They have used the known or guessed length of the target to find its AOB. Basicly its the same method as you find the range by mast high.

[panthercules]

btw ive seen pictures of a wiz wheel as it was used in german submarines. They have used the known or guessed length of the target to find its AOB. Basicly its the same method as you find the range by mast high.

Hmmm - now this sounded like a very cool (and relatively easy) idea at first - if you have a decent range estimate, and you can measure the observed/apparent length (presumably by reference to the markings along the horizontal/x-axis of the scope/TBT), it would seem to be a relatively simple matter of math/formulas to compute the AOB based on the relationship of the apparent length to the actual length (available from the recognition manual). However, I wonder if a wiz-wheel to do this would really be any easier to deal with than the Is-Was thing described in this thread, and this one seems to let you calculate either AOB or target course, depending on which data you already know, which is probably more useful than the above sort of special-purpose AOB calculator would be. Will have to see if I can put one of these Is-Was things together - sounds very cool.

[sqk7744]

Thanks CC!

That did the trick!

Cheers :up:

[Hitman]

Hmmm - now this sounded like a very cool (and relatively easy) idea at first - if you have a decent range estimate, and you can measure the observed/apparent length (presumably by reference to the markings along the horizontal/x-axis of the scope/TBT), it would seem to be a relatively simple matter of math/formulas to compute the AOB based on the relationship of the apparent length to the actual length (available from the recognition manual).

I'm finishing a tutorial with screenshots on a method to get the AOB based exactly on that. I call it the "Aspect Ratio" method, because it relays basically in how much the relationship between height and length of the ship you see changes towards the standard aspect ratio when at 90º AOB.

This is the part that dials with the AOB:


2.- AOB (ASPECT RATIO METHOD)

Each ship has its own "Aspect ratio", which means the difference of its length versus its heigth. For example, a 100 yards long ship with a mast of 33 yards has an aspect ratio of 3,33:1. Now, because what you can see of the ship’s height remains constantly proportional (The mast) at any given distance, while the length you can see will change also proportionally depending on the AOB, you can read from your scope or TBT the new Aspect Ratio the ship shows you, and by comparing it with the standard aspect ratio at 90º, get the AOB directly.


You just have to do this:


1.- Note the target’s Standard Aspect Ratio (F.e. 3.95 in a Medium Modern Composite). You can get it from the recognition manual (length 103.6 metres divided by a heigth of 26.2 metres in our Medium Modern Composite) and have it listed already for faster consulting.


2.- Pause the game (You are now a Tracking Party member), and count the scope marks until the top of her mast, and the marks from her bow to her stern (Hint: The scope locks at the exact centre, so just count from the centre to the bow fairwater and multiply by two). It is easier to do if you raise the reticle to align the horizontal division with the mast top, like the next image shows.



Divide the number of lentgh marks by the number of heigth marks, directly (No need to convert them to anything else). In our example, we see aprox 13.25 marks to the bow (26.5 marks total length of the ship) and almost exact 7 marks to mast top. Dividing it, the resulting value is 3,78


3.- Use following formula to determine the percentual variation of the aspect ratio:


New Aspect Ratio (3,78 in this case) x 100
Variation = _____________________________________

Old Aspect Ratio (3,95 in this case)


Variation in this case would be 95,8 %, i.e. nearly 96%


4.- Use this ruler (It is simply a Sinus scale) to determine the AOB:



In this case, 96% in the lower scale represents a 75º AOB, as you can see in the upper scale. Easy, isn’t it?

Now unstop the game, plug that value in your tool and send it to the TDC.

NOTE: If the target is heading away from you (No converging course) the result in degrees must be added to 90º. The aspect ratio variation will be the same if the target has an angle on the bow of 45º or of 135º, i.e. you will see 70% change towards the original Standard Aspect Ratio in both cases, so it is up to you to correct that. But its is fairly easy to see in general terms if the target is moving away or converging, and the masts of the ship will always provide you an orientation in the most difficult cases.

[don1reed]

Excellence awards to :

Capt K for iswas & Hitman for aspect ratio. Nicely done gentlemen. :up:

[WernerSobe]

well actualy the real AOB finder that ive seen pics of only needed the known length and "angle of projection" data. Seemed to be very easy and quickly to set up.

angle of projection is the ralative angle of the ship to your boat from bow to stern. You can find it by counting the horizontal marks in your persiscope. The manual says each mark is 1° or 4° depending on zoomscale.

[panthercules]

well actualy the real AOB finder that ive seen pics of only needed the known length and "angle of projection" data. Seemed to be very easy and quickly to set up.

angle of projection is the ralative angle of the ship to your boat from bow to stern. You can find it by counting the horizontal marks in your persiscope. The manual says each mark is 1° or 4° depending on zoomscale.

Well, I assume that you would still need to know something else besides the known length and apparent length ("angle of projection") - i.e., the range, because the apparent length will obviously be different at different ranges. I was thinking about a method that used the range directly, along with actual and apparent length, but that of course requires you to first determine the range and then input it into some formula/chart/wheel mechanism for solving AOB. The aspect ratio approach outlined above takes the range into account indirectly - since the apparent mast height also changes with range like the apparent length, by using the ratios of the two you don't need to actually determine or know the range to solve for AOB - you only need the apparent height and apparent length (to compare against the known values from the recognition manual or pre-determined aspect ratios from a chart), and both of those can be obtained from the 'scope - a clever way to avoid the stadimeter CTD bug for those who still have that :)

I'm not sure if I'll take the time to use these methods during combat, but they sound like a pretty good way to confirm my AOB estimates and "train" my eye during sub school practice to make better guesses using the Mark 1 Eyeball.

[Linton]

Perhaps this and any other device link could be made into a sticky??

[Hitman]

The aspect ratio approach outlined above takes the range into account indirectly - since the apparent mast height also changes with range like the apparent length, by using the ratios of the two you don't need to actually determine or know the range to solve for AOB - you only need the apparent height and apparent length (to compare against the known values from the recognition manual or pre-determined aspect ratios from a chart), and both of those can be obtained from the 'scope

Exactly that :D

As I had previously stated because what you can see of the ship’s height remains constantly proportional (The mast) at any given distance, while the length you can see will change also proportionally depending on the AOB, you can read from your scope or TBT the new Aspect Ratio the ship shows you, and by comparing it with the standard aspect ratio at 90º, get the AOB directly, so the range is irrelevant.

In the german method indicated by WernerSobe you must have at least one range readout, otherwise you have nothing because the same ship can f.e. extend 24 scope marks in horizontal at 90º AOB at 2000 yards or at 45º AOB at 1200 yards (Numbers not calculated precisely ). With my method that's not needed at all.:know:

[Dustyboats]

I agree that transparencies are not the best solution, but at least they're readily available to most people. My mock-up was made out of card stock and transparencies, and it seems to be holding up fairly well. But I like your idea of using clear lamination to give it strength; that's a lot simpler than what I was going to do (Which was make decals and put them on clear styrene sheets).

It's no problem to make a complete black and white one; it'll be a day or two at most.

I bought three different sized, circular plastic, school boys protractors. Cost UK £2.

[Miimike]

The back side is the run time calculator.

[Hitman]

Sorry sqk7744 but I think you got it wrong :-? Though I might be wrong, of course, but see if this example seems more correct:

http://img224.imageshack.us/img224/6779/banjo1bs8.th.jpg (http://img224.imageshack.us/my.php?image=banjo1bs8.jpg)

1.- Our own ship true course is 90, as highlighted in the red circle or our own ship BOW. The target's true course is 300º.

2.- We need to turn the scope left 60º, to our relative 300º, to see the target. The A ring scale is inverted exactly for that. When we turn the upper part of the scope left (Yellow arrow) we can correctly read in the opposite part of the scope ring that we have gone to the "300" mark of the A ring (yellow triangle marker in the handle), i.e. of our relative bearing. We also can see now in the middle ring (B ring of true course) that the relative course to our target would be 210º for us.

3.- Finally the AOB of the target can be read in the other scope ring marker (Highlighted with a green triangle). In this case it is 90º, not 120º as you had indicated. You got the wrong result because you reversed the own ship. This can be seen clearly in this edited picture of your setup:

http://img300.imageshack.us/img300/7796/bearing300qf6.jpg


Hope that helps:up:

EDITED to add:

The tool is in fact, as the name says, a "course finder" so in real life the inputs of the tool would be: 1) Own true course, 2) Target bearing and 3) Target AOB. With that input the tool would give you as output the true course of the enemy.
But in SH4 as in SH3 people tend to do the opposite, i.e. determine first true course of target and use the tool to get the AOB. Probably as someone highlighted in another thread, this is due to the AOB being more difficult to determine in a flat screen as opposed to real (3Dimensional) world, but anyway the real use of this wiz-wheel comes to be very clear when you play at 100% realism, i.e. with no map contact update and view limited to your bridge/scope/TBT.

Also, another problem with this wheel is that in SH4 we are used to see in the upper part of the scope the graded reticle for the target bearing, so we tend intuitively to look for the bearing in the upper part of the scope. But when doing so in this wheel, the AOB would be reversed! This is the main reason why the scale is reversed in the A ring: That you can have in the same marker (Scope ring handle) both target bearing and AOB. If you put one of them in the opposite side, you get a wrong reading, and if you put both in the other extreme, you have a reversed result.

[don1reed]

My take on this neat addition to whiz-wheels is:

You have 3 templates:

A (the big outer wheel) = True compass

B (middle wheel) = Submarine (all bearings relative)

C (inner wheel) = Target

Scope (transparency) = cursor

Here is a copy of my old orig SH1 whiz-wheel,

http://img256.imageshack.us/img256/6941/wizha6.th.jpg (http://img256.imageshack.us/my.php?image=wizha6.jpg)

as you can see, (forgive the blurriness), I've set it to the params of the problem. You need to do the same with the new wheel.

Cheers,

[WernerSobe]

well actualy the real AOB finder that ive seen pics of only needed the known length and "angle of projection" data. Seemed to be very easy and quickly to set up.

angle of projection is the ralative angle of the ship to your boat from bow to stern. You can find it by counting the horizontal marks in your persiscope. The manual says each mark is 1° or 4° depending on zoomscale.

Well, I assume that you would still need to know something else besides the known length and apparent length ("angle of projection") - i.e., the range, because the apparent length will obviously be different at different ranges. I was thinking about a method that used the range directly, along with actual and apparent length, but that of course requires you to first determine the range and then input it into some formula/chart/wheel mechanism for solving AOB. The aspect ratio approach outlined above takes the range into account indirectly - since the apparent mast height also changes with range like the apparent length, by using the ratios of the two you don't need to actually determine or know the range to solve for AOB - you only need the apparent height and apparent length (to compare against the known values from the recognition manual or pre-determined aspect ratios from a chart), and both of those can be obtained from the 'scope - a clever way to avoid the stadimeter CTD bug for those who still have that :)

I'm not sure if I'll take the time to use these methods during combat, but they sound like a pretty good way to confirm my AOB estimates and "train" my eye during sub school practice to make better guesses using the Mark 1 Eyeball.

youre right there was also the range involved.

[Hitman]

as you can see, (forgive the blurriness), I've set it to the params of the problem. You need to do the same with the new wheel.


Don, in my opinion you can't apply this to the wheel we are using because the outer ring has the ship silhouette -thus purpose made for own ship- and also inverted bearing scale. As I said before, the only way to make sense of that inversion is when turning scope left or right.:up:

[Igorry]

I like give my 2 cents worth on how to use the Is-was/banjo using cpt krunch example.

The Is-was/banjo has 4 dial

A dial is the submarine
B dial is the true compass
C dial is the periscope ruler
D dial is the enemy ship

The banjo can used to find the AOB of the enemy ship or the course of the enemy ship. However in each case three piece of information is required.

1) TO FIND AOB OF ENEMY SHIP

Three piece of information is require - your sub course, the relative bearing, the enemy course

a) Our sub course is 90 degree east.

According to cpt Krunch, he align B dial 90 degree to A dial at 0 degree.
I disagree that is the right procedure.

I think you should align B dial 90 degree to A dial at 180 degree. The triangle protruding out of the A dial is always the submarine bow and the opposite semicircle in dial A is the submarine stern.

b) From the periscope we spotted a ship and the relative bearing is 300 degree.

This is the same as capt Krunch. Move the periscope tab or c dial so that the outer marker in the periscope tab is over the A dial at 300 degree mark. Note in the periscope tab, there are two markers. One is pointing to A dial and the other is pointing to D Dial.

c) We have a contact heading 330 degree.

Move the D dial 0 degree (which represents the bow of the enemy ship) to B dial at 330 degree. (B dial is the true compass)

When you have done this, you can find AOB easily by reading from the periscope tab, the inner marker which points to the D dial at 120 degree port.

2) TO FIND THE COURSE OF ENEMY SHIP

Three piece of information required: The sub course, the relative bearing and the estimated AOB

a) Our sub course is 55 degree.

B dial 55 degree to A dial at 180 degree. The triangle protruding out of the A dial is always the submarine bow and the opposite semicircle in dial A is the submarine stern.

b) From the periscope we spotted a ship and the relative bearing is 260 degree.

Move the periscope tab or c dial so that the outer marker in the periscope tab is over the A dial at 260 degree.

c) Estimated AOB is 45 degree starboard.

Move the D dial starboard 45 degree to the inner marker of the periscope tab. At this point the outer marker is pointing to 260 degree of A dial and inner marker is pointing to D dial at 45 degree starboard.

To find the course of ship, read the 0 degree of D dial (which is the bow of the enemy ship) to B dial. You will find the enemy course to be 90 degree.

I hope I have not confuse the picture further. My only difference is that I believe the 180 degree in A dial is the bow of the sub where as the 0 degree is the stern of the sub.

Igorry

[don1reed]

Rgr that, Hitman.

I'm in the process of building one of the new w-w's. I'll follow your instruction tomorrow when it's completed. (kinko's)

tnx,

[Igorry]

My take on this neat addition to whiz-wheels is:

You have 3 templates:

A (the big outer wheel) = True compass

B (middle wheel) = Submarine (all bearings relative)

C (inner wheel) = Target

Scope (transparency) = cursor

Here is a copy of my old orig SH1 whiz-wheel,

http://img256.imageshack.us/img256/6941/wizha6.th.jpg (http://img256.imageshack.us/my.php?image=wizha6.jpg)

as you can see, (forgive the blurriness), I've set it to the params of the problem. You need to do the same with the new wheel.

Cheers,


Hi Don1Reed,

I have also constructed your whiz wheel and I believe the outer wheel is your submarine and the middle wheel is the true compass and the inner wheel is the target. Using your whiz wheel I can get the true course of the enemy ship or the enemy AOB with three piece of information

For true course

1) your sub course
2) relative bearing
3) Estimated AOB

For AOB

1) your sub course
2) relative bearing
3) True course of enemy ship


Basically the course finder or whiz wheel is the same as the banjo. I like the banjo better because it has the periscope tab and it is an exact copy of the ww2 banjo. However both can be used to find true course or AOB.

Igorry

[don1reed]

Basically the course finder or whiz wheel is the same as the banjo. I like the banjo better because it has the periscope tab and it is an exact copy of the ww2 banjo. However both can be used to find true course or AOB.

Igorry


Actually, Igorry, you & Hitman are both right...it's just a matter which of the templates the operator chooses to use as the True compass card.

...I like the new (more authentic for WWII) whiz-wheel too. The one I've been using is more from WWI.

-...-

sqk7744, your examples are very helpful, especially for the new guys using manual for the first time. :up:

[sqk7744]

moved to: http://www.subsim.com/radioroom/showthread.php?t=108931&page=2

[don1reed]

I think ya nailed it.

[sqk7744]

I think ya nailed it.
Cool!

A picture is worth a 1000 words.

Thanks again m'8 :up:

[bruschi sauro]

Very cool... thanks for well done job.:up:

[sqk7744]

Moved to: http://www.subsim.com/radioroom/showthread.php?t=108931&page=2

[tomoose]

I've made my own doohickey, whatchamacallit from your plans;) . Thanks for your efforts, much appreciated. I use it as initially described and not "upside down" as others have described. Personal preference. It works like a charm. I have found it has vastly improved my plotting and gives me a quicker and better method of determining a target's course and AOB. I have already used the IS-WAS to turn parallel to a prospective target's course, run ahead and then turn for an optimal 90-degree shot! Very gratifying. Unfortunately this has only been on SH III so far.

I've had better results with SH III as SH IV has become a pain in the arse. Current campaign has assigned me to patrol the Marshalls 5 times in a row!!. In all of those patrols I spotted and sank 1 single solitary japanese merchant. Frustrated I transferred to Australia and guess what, my next mission? Patrol the freakin' Marshall Islands!!!! Aaaaaaaaarrgh! I quit out and will wait for the next patch.:nope:

[Linton]

The back side is the run time calculator.
Would you be able to post a picture of that?

[bruschi sauro]

I've made my own doohickey, whatchamacallit from your plans;) . Thanks for your efforts, much appreciated. I use it as initially described and not "upside down" as others have described. Personal preference. It works like a charm. I have found it has vastly improved my plotting and gives me a quicker and better method of determining a target's course and AOB. I have already used the IS-WAS to turn parallel to a prospective target's course, run ahead and then turn for an optimal 90-degree shot! Very gratifying. Unfortunately this has only been on SH III so far.

I've had better results with SH III as SH IV has become a pain in the arse. Current campaign has assigned me to patrol the Marshalls 5 times in a row!!. In all of those patrols I spotted and sank 1 single solitary japanese merchant. Frustrated I transferred to Australia and guess what, my next mission? Patrol the freakin' Marshall Islands!!!! Aaaaaaaaarrgh! I quit out and will wait for the next patch.:nope:yes we wait for the new patch:cry: but when we can get it?:cry:

[Front Runner]

The Is-Was goes together with the Publication 1310 very nicely.
I have found a site for a free official download of Pub 1310.

http://www.subsim.com/radioroom/showthread.php?t=110484

[sqk7744]

The Is-Was goes together with the Publication 1310 very nicely.
I have found a site for a free official download of Pub 1310.

http://www.subsim.com/radioroom/showthread.php?t=110484

Bravo! :up: :up: :up:

[simple nuke]

I spoke to a retired Submarine C.O. on Saturday, who originally qualified on an S Boat. He told me that the Is-Was was a circular slide rule that was used to calculate the rate of change of the target's bearing from the submarine, in order to determine the course of the torpedo. On the S Boats, the periscope was normally used in the Control Room, next to the Tracking Party. The target's AOB, Range and Speed (Is) was compared to what those values where (Was) after some measured time. The Bearing Rate Change was used by the Tracking Party, along with the boat's course and speed, to calculate the Target's course and speed, and then calculate the torpedo's course and when to fire, based on a known torpedo speed.

After the adoption of the TDC, the Is-Was was used as a means to check the TDC solution and for use incase of TDC failure.

[Hitman]

Yes that's right, this is how the rear part of the wheel works, I found it out recently and I'm already working in the graphics. :up: It is more or less like this:

1.- You detect the target, identify it, take bearing and range and make a guess of the AOB, then plug the values into the part of the wheel we have already. Now you have an idea of the course and can plot an intercept

2.- You make a second observation some time later (Note bearing, range and time between observations) and then turn around the wheel and use the rear part: You start by fiddling around with the medium wheel until the difference in bearing matches and find the AOB with that. You guess of the AOB in the first observation helps you start already with an aproximate solution. Now you read across the wheel and know also the distance travelled. It's time then to use the inner wheel and adjust the "time" between observations to that distance travelled -read in the outer wheel- and bingo! you can directly read target's speed at the outside ring:D Wondeful tool, isn't it?:rock:

Stay tuned, I will post a downloadable template ASAP for the rear part of the wheel with a tutorial:D

[sqk7744]

Yes that's right, this is how the rear part of the wheel works, I found it out recently and I'm already working in the graphics. :up: It is more or less like this:

1.- You detect the target, identify it, take bearing and range and make a guess of the AOB, then plug the values into the part of the wheel we have already. Now you have an idea of the course and can plot an intercept

2.- You make a second observation some time later (Note bearing, range and time between observations) and then turn around the wheel and use the rear part: You start by fiddling around with the medium wheel until the difference in bearing matches and find the AOB with that. You guess of the AOB in the first observation helps you start already with an aproximate solution. Now you read across the wheel and know also the distance travelled. It's time then to use the inner wheel and adjust the "time" between observations to that distance travelled -read in the outer wheel- and bingo! you can directly read target's speed at the outside ring:D Wondeful tool, isn't it?:rock:

Stay tuned, I will post a downloadable template ASAP for the rear part of the wheel with a tutorial:D
---
Thanks Hitman! Can't wait- I've been having great fun using Cap'n Cox's Is-Was (AOB side) hope my tutorial was helpful!

Cheers M8 :arrgh!:

[Captain Krunch]

Everyone, the good folks over at the Historic Naval Ships Association have posted "Submarine Attack Course Finder Mark 1 Model 3 Manual, O.D. 453" (http://www.hnsa.org/doc/attackfinder/index.htm), so we no longer have to guess how the heck to use the Is-Was! In addition, this manual has some fairly clear images of the back side of the Is-Was, so I might eventually be able to complete what I've already put together - but I probably won't be able to get to it for a while, so anyone else can feel free to step up and create the back side of this thing.

[jmr]

Damn I love this stuff! Thanks for that link and boy I can't wait for Hitman's work to be finished and uploaded :up:

[CaptainHunter]

Finally I can get AOB right every time.
I use it this way....I set my heading on (B) to zero on (A) then set (P)reading to (A)then go to map and get enemy vessel heading and set it to the (B)scale now look at the periscope finder where the pointer touchies the (C)scale and that is the AOB.

Thanks :know:

[Puster Bill]

Everyone, the good folks over at the Historic Naval Ships Association have posted "Submarine Attack Course Finder Mark 1 Model 3 Manual, O.D. 453" (http://www.hnsa.org/doc/attackfinder/index.htm), so we no longer have to guess how the heck to use the Is-Was! In addition, this manual has some fairly clear images of the back side of the Is-Was, so I might eventually be able to complete what I've already put together - but I probably won't be able to get to it for a while, so anyone else can feel free to step up and create the back side of this thing.


Sounds like I've 'reinvented' the wheel, so to speak. The backside of the banjo is simply a circular slide rule with a few extras to make it easier to use for targeting (especially compensating for own speed).

What I did was take the banjo, and put it on the back of a circular slide rule that I got from the Sphere Research site (http://www.sphere.bc.ca/test/build.html). You want body image 1, print it out on cardstock, use a highlighter to highlight the S scale, then laminate it. Print the overlay/cursor image on inkjet transparency, then laminate it also (helps make it more rigid and durable). I pinned them back to back, and it looks like this...

Slide rule side:
http://img107.imageshack.us/img107/9923/picture020yq9.jpg

'Banjo' side:

http://img454.imageshack.us/img454/5909/picture021ds0.jpg

I would really be interested in getting that other side, though.

[Hitman]

http://img490.imageshack.us/img490/4489/rulerfinalsamplefg1.jpg


Don't worry I have already finished it :rock: This weekend I'll do some test to print and see it has the correct size, and will upload as soon as I have it al ready:up:

[jmr]

Print the overlay/cursor image on inkjet transparency, then laminate it also (helps make it more rigid and durable).

Do you get bubbles when you laminate those inkjet transparencies? That's what happened to me when I laminated mine :{

[Puster Bill]

Print the overlay/cursor image on inkjet transparency, then laminate it also (helps make it more rigid and durable).
Do you get bubbles when you laminate those inkjet transparencies? That's what happened to me when I laminated mine :{

You have to be careful. Go slowly, and if you see a bubble developing smooth it out while there is still a place for the air to escape.

Failing that, take a pin and poke a tiny hole in the lamination at the center of the bubble. Smooth the edges of the bubble inward towards the hole.

[Onkel Neal]

Really nice find and nice work!

Neal

[Bill Nichols]

Really nice find and nice work!

Neal

I'm disappointed, Neal. I was hoping you were going to announce that you would be selling a 'Subsim Special Edition' Banjo. :cry:

[CaptainHunter]

I was looking at this link today @ work, that someone posted in this thread earlier, it shows the original instructions.

scroll down to the bottom for a really nice pic.

http://www.hnsa.org/doc/attackfinder/index.htm

[Rip]

Really nice find and nice work!

Neal
I'm disappointed, Neal. I was hoping you were going to announce that you would be selling a 'Subsim Special Edition' Banjo. :cry:

How much?

:rock:

:88)

:sunny:

[Hitman]

I'm disappointed, Neal. I was hoping you were going to announce that you would be selling a 'Subsim Special Edition' Banjo. :cry:

Argghhh you ruined the surprise! I have been looking here at local plastic stores to see how much they would ask for doing them in laminated plastic:x

[Meridian]

Well, if it looks as good as the one in this link http://www.hnsa.org/doc/attackfinder/index.htm i'll take one

[MadMike]

That's not a banjo, THIS is a banjo-

http://hnsa.org/doc/banjo/img/pl1.jpg

Mk8 Torpedo Angle Solver

http://hnsa.org/doc/banjo/index.htm

Referenced as being used on S-27 when she ran aground on Markarius Point, Amchitka.

Yours, Mike

[Hitman]

I have finished the templates and have already built mine:rock:

Here are the printable images in BMP format for everyone to build and enjoy: http://rapidshare.com/files/28399815/Printable_IS-WAS.rar.html

Have fun and sink 'em all!

[don1reed]

Excellent work, Hitman, and tnx.

[CaptainHunter]

:rock:Thanks

[jmr]

Woohoo!

[Meridian]

Thanks Hitman.

[CaptainHunter]

For some reason it didn't come out the same size as my other one? no biggie I just use it separately.

[Hitman]

For some reason it didn't come out the same size as my other one? no biggie I just use it separately.

How much is the difference? I can't guarantee what size it will come out by printing with different measuring systems or hardware combinations:dead: But in any case you should be able to resize it with any decent graphics editor. If someone did a PDF version like Kaptain Krunch was, that would probably solve any problems:88)

[CaptainHunter]

It's around 3/8" smaller they first one I made of the front.

[Puster Bill]

OK, I don't really know why I did this, as I only have SHIII, and the basic unit of measure is meters instead of yards, but here is my attempt at making the "SUBMARINE ATTACK COURSE FINDER MK. 1 MOD. 3":

http://img396.imageshack.us/img396/8539/picture026bb9.jpg

http://img396.imageshack.us/img396/9431/picture027rl0.jpg

So, what do you think?

On edit: Big tip o' the hat to Hitman. There is a *SLIGHT* size difference, but it is minimal if you print the .pdf's at 94% size, and print the slide rule .bmp's fitted to the paper (8.5x11).

[Hitman]

On edit: Big tip o' the hat to Hitman. There is a *SLIGHT* size difference, but it is minimal if you print the .pdf's at 94% size, and print the slide rule .bmp's fitted to the paper (8.5x11).

Strange thing is that my printed version came out with nearly exact size. It wasn't perfect either, but since I had not been able to exactly cut with my scissors the part done by Kaptain Krunch I gave it as a godo result.:hmm:

I can however easily resize the images to 94% of their current size with Photoshop. Think there will be no noticeable quality difference:88)

I don't really know why I did this, as I only have SHIII, and the basic unit of measure is meters instead of yards

It works as well except for the minimal difference it causes in the speed measurement, because a yard s approx 0.93 of a meter. But you can apply also that proportion to the results and that's good enough.

I am thinking about creating a version for SH3, simplified and with metres as units, as well as with Kriegsmarine emblems. :smug: Any interest?

[Puster Bill]

On edit: Big tip o' the hat to Hitman. There is a *SLIGHT* size difference, but it is minimal if you print the .pdf's at 94% size, and print the slide rule .bmp's fitted to the paper (8.5x11).
Strange thing is that my printed version came out with nearly exact size. It wasn't perfect either, but since I had not been able to exactly cut with my scissors the part done by Kaptain Krunch I gave it as a godo result.:hmm:

I can however easily resize the images to 94% of their current size with Photoshop. Think there will be no noticeable quality difference:88)

I don't really know why I did this, as I only have SHIII, and the basic unit of measure is meters instead of yards
It works as well except for the minimal difference it causes in the speed measurement, because a yard s approx 0.93 of a meter. But you can apply also that proportion to the results and that's good enough.

I am thinking about creating a version for SH3, simplified and with metres as units, as well as with Kriegsmarine emblems. :smug: Any interest?

Yes, please.:rock:

[jmr]

[quote]I am thinking about creating a version for SH3, simplified and with metres as units, as well as with Kriegsmarine emblems. :smug: Any interest?


HELL YES I'ld love to have one specifically for SHIII.


By the way, Bill, I went over to Kinko's to use their laminator and I still ended up with bubbles when laminating my transparancies :{ There's no speed setting so I had to go "slow" by pulsing the on/off switch but that still didn't work out too well.

[starbird]

I used the self stick laminating sheets. Put them sticky side up on the table, and put one of the wheels down on top of it, starting from one side. It came out without any bubbles.

[jmr]

Damn I didn't even think about using those and I bet that's what Bill was refering to in the first place.

*doh!*

[CaptainHunter]

http://img168.imageshack.us/img168/8505/picturefp2.jpg

[Puster Bill]

I am thinking about creating a version for SH3, simplified and with metres as units, as well as with Kriegsmarine emblems. :smug: Any interest?

Upon a little reflection, there are a couple of 'improvements' I would suggest.

First, instead of having an 'arm' on the minute wheel, make it into a cursor. In other words, you would print out the minute wheel (the smallest of the three) on a transparency, with just a line radiating out from that wheel at the place where the arm comes out. I suggest this because when you print out the minute wheel as-is, the arm partially obscures the speed reading.

In addition, another line not connected to the wheel, and with a small line crossing it at one end, on the same 'page'. This would be for an additional cursor, which would be helpful for aligning the bearing wheel with the distance scale on the large wheel (but isn't really necessary, just helpful).

[Puster Bill]

Damn I didn't even think about using those and I bet that's what Bill was refering to in the first place.

*doh!*

Yep, that's what I use.

[Puster Bill]

Another idea, if you are handy with tools, is to print the wheels on those opaque white inkjet sticker sheets, then stick them to thin acrylic sheets. You then laminate the tops, and cut the acrylic to shape. That would make them absolutely rigid.

[Mav87th]

I have printed on Overhead Projector transparents and i had those laminated with a heavy lamination.

That is really rigid and still transparent like glass. And the printing is sharp and crisp.

Only the biggest (background wheel) wheel is printed on a thick paper and heavy laminated.

[Igorry]

Can someone pm me and send me the reverse side of the is-was done by Hitman? I don't seem to be able to download from rapidshare. Thanks

Igorry

[Hitman]

First, instead of having an 'arm' on the minute wheel, make it into a cursor. In other words, you would print out the minute wheel (the smallest of the three) on a transparency, with just a line radiating out from that wheel at the place where the arm comes out. I suggest this because when you print out the minute wheel as-is, the arm partially obscures the speed reading.


Doh:doh: I forgot to add in the readme that the centre wheel (Time wheel) is to be printed in a transparency:damn: , not in solid paper. For mine, I just printed it solid but made the arm out of transparent plastic I cut for that, so the arm does not obscure the reading:smug: Anyway don't worry, I'm thinking of some different items I'm going to modify for the SH3 wheel as I also want it to look different -not US but german like- Thanks:up:

[jmr]

I have printed on Overhead Projector transparents and i had those laminated with a heavy lamination.

That is really rigid and still transparent like glass. And the printing is sharp and crisp.

Only the biggest (background wheel) wheel is printed on a thick paper and heavy laminated.

How did you laminate those overhead projector transparencies without having the ink smeared?

[XanderF]

I am thinking about creating a version for SH3, simplified and with metres as units, as well as with Kriegsmarine emblems. :smug: Any interest?

Would be fun to have, but...how historical? I'm only aware of the US using a device like an "is-was". Certainly, the math is simple enough, but...did the KM actually have an analog to this, or just use sliderules?

[don1reed]

@XanderF:

Here's what the Kriegsmarine used:

http://img255.imageshack.us/img255/7871/tdcwheelzl1.th.jpg (http://img255.imageshack.us/my.php?image=tdcwheelzl1.jpg)

[XanderF]

Oh, now, see, that's ten times as spiffy!

EDIT: Hmm...don't see anything for the speed solution, though? Does it have a back?

[jmr]

Woah is that yours don?

[Mav87th]

I have printed on Overhead Projector transparents and i had those laminated with a heavy lamination.

That is really rigid and still transparent like glass. And the printing is sharp and crisp.

Only the biggest (background wheel) wheel is printed on a thick paper and heavy laminated.

How did you laminate those overhead projector transparencies without having the ink smeared?

I went to a Copying house company - they did a marvelous job for very small money. NOTHING is smeard at all.

[don1reed]

I wish it was mine (German Is-Was). I don't have a clue of whats on the flip side.

[Hitman]

Here's what the Kriegsmarine used:


Great picture, do you have more?

Only problem I have found is that because unfortunately the german TDC in SH3 is wrongly represented (AOB input instead of target course input) I must conform the wiz-wheel to give as output what you actually plug into your SH3 TDC, and not what was really plugged into the real german one. :damn: So I will make something a bit hybrid between german and US methods:hmm:


FYI I have started a thread in the SH3 forum announcing I'll do a wiz wheel for SH3, so keep an eye on that one.:up:

[don1reed]

No more pics. Found the German Is-Was pic in an obscure book on modern Subs. I believe the Germans were more into using sliderules and trig, based on all I could find. There may yet be some hidden treasure out there that someone will share with us. :) Good luck with the model for SH3.

[Hitman]

Interestingly, because trigonometry is the same all over the world, the germans made wiz wheels that are near exact matches to the US ones. Take a look at this edited pic I posted also in the SH3 IS-WAS thread:
http://img477.imageshack.us/img477/8123/germanwizwheelmy5.jpg

Every item of the Submarine Attack Course Fnder MK3 is there:

-Outer ring with inverted scale for target bearing (The white inverted triangle on the magent background, up in the image, is the bow of the U-Boot, where the true course ring must be aligned with) + Transparent layer to represent periscope/Uzo bearing

-Middle wheel for true course of both own ship and target

-Inside wheel for target AOB

-The only thing it adds as extra is the ring for the track angle:hmm:

I bet that the reverse side of this wheel is also nearly exact to the Submarine Attack Course Fnder MK3 :yep:

[don1reed]

I don't doubt it for a minute, Hitman. Hopefully, someone out in www would grace us with the flip side.

...at any rate, I was very much impressed with the strudy construction techniques. It was made to last unprotected.

cheers,

[CeeBee]

This is for Captain Crunch & Hitman: thanks for your excellent work on the Is-Was! I read this thread through and would really have use for the excellent tool(s) you've done. I tried to use RapidShare to download the files, but I am constantly running into ridiculous download waiting times of over two hrs, then when I get almost to 0 waiting time, the timer is reset again to 120 minutes - or I get an error message claiming that I have another download ongoing already although I actually haven't.

So please please, if you or someone else can find another place to host the files for me to get, my eternal gratitude would be yours! :)

[DirtyHarry3033]

Thanks to Captain Krunch and Hitman for this great Is-Was :up: Have spent a very enjoyable afternoon building it, now comes the fun part - learning how to use it!

I went all-out on making it, using 110 lb card stock and inkjet transparencies, then took it all to Office Depot to have them laminated in the heavy stuff. Jeez, I spent more on this than SH4 cost to start with :o I must be sick, is there a 12-step program to get off subsimming?!?!?!

(Course I also did Kim Ronhof's fine tools too so that increased the laminating costs...)


Now, there are only 2 things I don't like about Hitman's side of the Is-Was (note that no criticism is implied here, I appreciate his work and there's no way I could have done it myself!):
For some reason, the outermost circle on the inner and middle wheel did not print for the most part. This made it very difficult for me to cut it out accurately since there was no clear line to follow - 43 years ago in kindergarten, I consistently failed the work where you had to cut the construction paper along the lines :rotfl::rotfl:Also it wasn't a printer problem as the lines don't show up clearly on screen either.
As a couple others have said, it don't print the same size as Captain Krunch's front side.I fixed both of those problems, I loaded the inner and middle wheel into Paint Shop Pro 9 and made a new outermost circle for them. They print great now, much easier to cut out!

I also found that (on my hardware anyway...) by printing in PSP9 and scaling all Hitman's wheels up to 106%, it is a near-perfect fit for Captain Krunch's wheel.

If anyone is interested and if Hitman would give his OK, I'd be glad to provide him with the modified inner and middle wheels to include in his package. The only thing I changed is to make a clear outer circle on them so they're easier to cut out accurately.

How about it Hitman, wanna take a look at them? If you do, PM me and I'll be glad to send you both the PSP and .bmp files :up:

DH

[Hitman]

I also found that (on my hardware anyway...) by printing in PSP9 and scaling all Hitman's wheels up to 106%, it is a near-perfect fit for Captain Krunch's wheel.

If anyone is interested and if Hitman would give his OK, I'd be glad to provide him with the modified inner and middle wheels to include in his package. The only thing I changed is to make a clear outer circle on them so they're easier to cut out accurately.

Sure, just upload them wherever you want and add a readme with your modifications:up: . The funny thing is that they print perfectly in my hardware :-? and some people have reported that the difference is 96% instead of 106%:-?

That will also probably help CeeBee getting them.:up:

[don1reed]

Howdy, Hitman.

I may be behind the "curve" on this, but,

Using your side of the Submarine Attack Course Finder/Is Was (SACF), and in reality it is nothing more than a Circular Sliderule with Sine scale only, it can also be used as an ASPECT RATIO (AR) tool:

As we know, all the AR are based on a 90° AoB.

1) After IDing the target ship and obtaining it's AR, adjust the center wheel of the SACF, placing the 90° mark under the AR of the target.

2) After obtaining new AR thru objective lens of the scope, use the clear cursor, sliding it to the new AR and reading the Aob under it.

:|\\ Using the "Tool" eliminates any pause-the-game math.

Here's a pic:

http://img511.imageshack.us/img511/8637/sacf2rs3.th.jpg (http://img511.imageshack.us/my.php?image=sacf2rs3.jpg)

[Hitman]

and in reality it is nothing more than a Circular Sliderule with Sine scale only, it can also be used as an ASPECT RATIO (AR) tool:


Sure Don, well spotted!:up: I had thought that since it is -as you say- a sine scale there should be some way of reading it, but I did not dig deeper because I use another item for calculating the AR. But you found it and it is much easier than I had thought at first sight:up:

[don1reed]

Hah, I think we've reinvented the wheel...so to speak.:D

Grand Dad always said, "...Tain't nothin' new under the Sun."

[don1reed]

One last item from my corner:

Do the Math.

I observe thru the scope a Hakusika Maru: Aspect Ratio 4.6 from the book.

Aspect Ratio thru the scope:
4.25 tics high
13 tics long.

Do I break out my hh electronic calc ? No, I reach for the SACF/IW:

http://i77.photobucket.com/albums/j42/donhreed/sa1.jpg

Since the SACF is a cicurlar sliderule (logrithmic) with a sine scale:

As you can see, 25.1° falls beneath 4.25, the height of the target ship, so I then rotate the center disk to place the 25.1° mark under 13, dividing 4.24 into 13. The answer is read above the sine of 90° = 3.05, the observed Aspect Ratio.

http://i77.photobucket.com/albums/j42/donhreed/sa2.jpg

I can now proceed to compare the two AR's to obtain my Angle on the Bow with the SACF.

4.6 : 90° : : 3.05 : 42°

http://i77.photobucket.com/albums/j42/donhreed/sa3-1.jpg

Simple and fast


EDIT NOTE: Had to goto photobucket, ImageShack is having a bad day.

[Hitman]

Brilliant:up: :up: :up:

As I said before, I am using a purpose built ruler that makes it all more intuitive, but you are proving constantly how easy it is also with the MK3 once you get the hang of it. I take it you are also using the aspect ratio idea? Does it work well for you?

Cheers

[don1reed]

Aspect Ratio concept:

I can honestly say, no, Hitman. I was just using, "a sailor's eye" for obtaining Ab . Your influence with AR and the Side 2 have greatly made these Sims alot more interesting. Outstanding!

I look back over the years of playing subsims ... don't know how I was able to sink anything without...doing the math. :up:

[joegrundman]

Greetings, I'm new to this forum, but I also have to add that the SACF has totally revolutionised my style of play. To think I used to use fast 90 targetting! Now target tracks of 100 or 110 degrees every time.

I've written a tutorial on how to use the wheel to conduct passive sonar only approaches in conditions of poor visibility, rough weather, or when it is otherwise impractical to rely on frequent periscope sightings (obviously a minimum of one sighting is still required before firing). Is there an appropriate place to offer such tutorials?

I still play SHiii, but guess what I found when looking down in the bridge of my type VIIC? Right in the middle of the conning tower...if only they'd made it functional :cool:

thanks

[MudMarine]

This has gotta be posted to a sticky! I just made the front side this week end. When I get time I will atemp the back side.

[don1reed]

Ooorah!:up:

[GOZO]

Splendid! This little gem adds to immersion for sure.:up:

Now my problem is downloading...:-?

Are you sure the link works?:hmm:

Cheers

/Per

[sqk7744]

One last item from my corner:

Do the Math.

EDIT NOTE: Had to goto photobucket, ImageShack is having a bad day.
WONDERFUL to see the other side of this gadget!!!! Many thanks for posting. :up::up::up:

Just incase, here's my Ol' tutorial for the Front, AOB side:


"But let's pretend you don't change course. Ok, now the last bit of the puzzle is Angle on the Bow. You have two ways to use this. First, if you can determine the true course of the contact via plotting, you can input the contact's heading to determine AoB. "Sir, contact heading is plotted out to be 330 degrees!" You do not move the A, B, and Periscope dials; you move the C dial until the "0" degrees mark of the C dial is pointing to the "300" degrees mark of the B dial. When you do this, you look at the Periscope dial marker 180 degrees opposite the Periscope triangle. This marker points at "120", on the left side of the C dial ship, so this tells you that the contact AoB is 120 degrees port"
Krunch ----

The following (hopefully) illustrates Capn Krunches' example:
(it appears C (Enemy Vessel) wheel's 0 points to 330 and not 300, is that correct?)

BIG Thanks to Igorry for the Clarification on the Bow oriented up (12 o’clock position) and to Hitman for pointing out that the heading was 330 and not 300.

I wanted to provide an easy, clear 3D example of how this looks for my Mates on the Forum.

Cheers!

-----------------
Visual Aids...Yes Nurse Ratchet let me have an extra hour of arts and crafts time.

And now for the Players:

First-up The USS "Onkel" Stevens
http://www.compuglobalhypermeganet.tv/images/sh4/IsWas/USS_Stevens.jpg

Next, "The Enemy"
http://www.compuglobalhypermeganet.tv/images/sh4/IsWas/enemy.jpg


[The Set-up]
1) Sub Heading: 90
2) Target heading: 330
3) Target Bearing: 300
4) Target AOB: 120

1) USS "Onkel" Stevens Heading 090 (align your heading 090 on Wheel B to 180 of wheel A)
* Note Submarine examples do not contain the C Wheel for simplicity
http://www.compuglobalhypermeganet.tv/images/sh4/IsWas/SUB090.jpg

2) Our Target Heading 330 (Align the 0 (zero) on Wheel C to Target course 330 of Wheel B)
* Note Target examples do not contain the Transparent Periscope Wheel for simplicity
http://www.compuglobalhypermeganet.tv/images/sh4/IsWas/Target330.jpg

3) TARGET BEARING 300 relative Sir! (Set the inside Arrow of the transparent Periscope Layer
"highlighted in Red" to 300 on the A Wheel.)
http://www.compuglobalhypermeganet.tv/images/sh4/IsWas/Bearing300.jpg

4) AOB=120 to Port Sir (now look at The Arrow Tip of the Periscope Layer on the A Wheel)
* Note: if the C (3rd inner) wheel were included the Tip of the Periscope Arrow wheel would point to 120.
This can be seen on the Is-Was image.
http://www.compuglobalhypermeganet.tv/images/sh4/IsWas/AOB.jpg

And as shown on the Is-Was
http://www.compuglobalhypermeganet.tv/images/sh4/IsWas/Is-Was.jpg
[In Summary]
The Photos:
1) Our Sub's Heading: 90
2) Target heading: 330
3) Target Bearing: 300 (the inside Arrow of the transparent Periscope Layer "highlighted in Red" on the A Wheel.)
4) Target AOB = 120 Shown by the Tip of the Periscope Arrow wheel Highlighted in Red Pointing at the C Wheel

The Wheels:
A Wheel = Azimuth Circle (Our Periscope/Submarine)
B Wheel = Compass Rose (True Heading)
Transparent Wheel = The Periscope/TBD/Binoculars "bearing" to target
C Wheel = Enemy/Target ship Heading

Hope this is correct and helpful!

Enjoy

[Couldn't resist the result!] :arrgh!:

"BOOOOOOOOM!"
http://www.compuglobalhypermeganet.tv/images/sh4/IsWas/Boom.jpg

Load #3 Torpedo Attack:

Here's what you should see after a minute or two into the simulation:

Subs' Heading = 000 due north and speed 0
Target heading = 102.674 (let's use 100)
Bearing to Target = 325
AOB = 45 (42 if using Target heading of 102-103)
Target speed = 9knts

* TIP: once in Map view F3 hit backspace to pause the sim. When ready, hit the NumPab + (plus) key to continue.

You can check this by drawing a line out from your sub's center with the distance tool on your course to the 8^ 13' N

Now draw another line from the target's center until it intersects your course line.

Take the Protractor and draw a line from the Intersection point to the Target's bow, now left-click and draw another line to your bow. The Angle on the Bow should = 45 degrees for AOB=45.

Enjoy, Cheers!

[sqk7744]

I have finished the templates and have already built mine:rock:

Here are the printable images in BMP format for everyone to build and enjoy: http://rapidshare.com/files/28399815/Printable_IS-WAS.rar.html

Have fun and sink 'em all!
BRAVO HITMAN!!!

Take a Bow! :know:


* With PSP XI set to 112% fits Capn' Cox's Front Side .pdf perfectly

[dertien]

Hello there everyone,

Instead of going cardboard and paperwise, I went to flash and made the front part of your wheel.

Thanks to Captain Krunches pdf files, I came up with this online version.

Flash player required

http://img456.imageshack.us/my.php?image=iswasxc2.swf&width=1024

Does anyone have good photos of the german version of the whizz wheel ?

I would like to model that in flash, but can't find any good pictures.

[Crosseye76]

Very cool Dertien !

[don1reed]

Yes, very nice job, dertien.

btw: in answer to your question:

go here: http://www.subsim.com/radioroom/showthread.php?t=114351

[sqk7744]

Awesome work! :up:

[Captain Krunch]

Well, I'm very glad that everyone has been happy with the work I did way back in March, and I'm also glad to see others run with it by making the back side and creating the Flash version.

Sadly, after I published the front of the Is-Was, I did a cross-country job relocation & bought a new house - both of which prevented me from participating further in this discussion (Or playing SH4 for that matter; I haven't played more than 10 minutes of it since it came out!). Hopefully I'll get into it later this year and enjoy the hard work that we've all done on the Is-Was.

Krunch

[sqk7744]

Well, I'm very glad that everyone has been happy with the work I did way back in March, and I'm also glad to see others run with it by making the back side and creating the Flash version.

Sadly, after I published the front of the Is-Was, I did a cross-country job relocation & bought a new house - both of which prevented me from participating further in this discussion (Or playing SH4 for that matter; I haven't played more than 10 minutes of it since it came out!). Hopefully I'll get into it later this year and enjoy the hard work that we've all done on the Is-Was.

Krunch

Welcome back Capn' :up:

[usscod]

Well, I'm very glad that everyone has been happy with the work I did way back in March, and I'm also glad to see others run with it by making the back side and creating the Flash version.

Sadly, after I published the front of the Is-Was, I did a cross-country job relocation & bought a new house - both of which prevented me from participating further in this discussion (Or playing SH4 for that matter; I haven't played more than 10 minutes of it since it came out!). Hopefully I'll get into it later this year and enjoy the hard work that we've all done on the Is-Was.

Krunch

I just finished making a model of the Is-was using your excellant pdf file downloaded from the HNSA website. In my experimenting for materials to use I found some 7-mil transparancy film from B&K Photo (which just arrived today). Once I figured out that ink will only dry on the coated side I made up the C & D elements by printing them and then laminating them before cutting them out. They are quite stiff and flat and, of course, the ink is protected from wear and smearing.

The device works beautifully! I just happened to notice your earlier remarks about the orientation of the "A" ring and would point out that this ring corresponds to the relative bearing ring on the actual periscope housing. The "B" ring corresponds to the gyro repeater -- so it's scale represents true coordinates.

Thanks for all our effort in making up the drawings, and thanks for making them available. BZ!

John Fakan

[Sailor Steve]

WELCOME ABOARD!:sunny:

[don1reed]

Good Job, Cod.

And I echo, Steve's welcome.

...where would we be CPT K w/o your genius?

at sea, adrift, w/o a rudder. Tnx agn.

[klh]

I'm trying to build this one (I finished the KM version and love it), but I'm a bit confused. On the front side, I see the C ring and the periscope ring. I have two questions:

1. Should both be transparent?
2. What order are they stacked? It looks like from the pictures that the periscope ring is on top, but I also see that it's the same size as the C ring. If that's so, how do you turn the C ring underneath?

[Hitman]

I had to add a small handle for that purpose when cutting the disk. I placed it at the 180º mark, but it can be anywhere. Probably in the real item the disk is so fixed to the central axis that you do not have the problem, but in the custom buit tool you certainly hve difficulties turning that disk as the scope disk (On top of it) hides it completely. Good catch klh :up: in my first attempt to build the tool I noticed that too late :damn:

BTW the C disk can be made solid or transparent, as it doesn't interfere with others. In the original tool it is apparently transparent, but again it's not necessary.

Hope that helps

[ReallyDedPoet]

Welcome to SUBSIM :up: usscod


RDP

[klh]

Hope that helps

That helps immensely. I'll work on it over the weekend. Gracias Hitman!

[Captain Krunch]

When I look at a picture of a real one, it appears to me that the C disk is on top of the Periscope disk, which in turn is on top of the B & A disks. The C & Periscope disks are transparent. This is how my home-made one is. The only problem with this is that the C disk curls up, but it's easy to live with.

[klh]

Thanks Krunch and Hitman! Now if I can only find a mechanical stopwatch, I would be in Subsim Paradise.

Front:
http://img66.imageshack.us/img66/6163/img3260oa5.jpg (http://imageshack.us)

Back:
http://img61.imageshack.us/img61/9827/img3261jo1.jpg (http://imageshack.us)

[Captain Krunch]

Wow! That looks great! A lot better than my cruddy version. How did you go about doing it? Did you use a laminating machine? I'm thinking that's the only way to go, to keep the various layers flat. I went the cheap route and used some SelfSeal repositionable laminating sheets, but they just don't cut it - too floppy.

[klh]

I used a thermal laminator over cardstock. The clear parts I used transparency with two layers of lamination. They are fairly rigid, but keep in mind the picture doesn't show all the imperfections.

[kverdon]

Greak Work KLH! You should make some of those and put them on Ebay!

[klh]

Greak Work KLH! You should make some of those and put them on Ebay!

Thanks, but really the credit goes to Hitman and Captain Krunch. All I did was follow instructions.

[ktrboston]

To KLH and Capt. Krunch,
I found your posts very helpfull particually the link KLH posted
http://hosted.filefront.com/khaehl/ and the Capt. Krunch explaination of the Course finder tool. Both where very helpfull. I got more understanding from reading Angriffscheibe_Handbuch. Reading this gave me a better understanding of attacking and fingure out values of the attack(TB, AOB, etc...) Also want to give thanks to all who helped you. Now lets see if I can put it into action! The course finder I made is very crude, but it does the job.

[CDR Resser]

Thanks for the work on this. I just completed my US Navy Is-Was and its Kriegsmarine equivalent. The templates and instuctions made the process relatively painless.

Respectfully Submitted;
CDR Resser

[klh]

To KLH and Capt. Krunch,
I found your posts very helpfull particually the link KLH posted
http://hosted.filefront.com/khaehl/ and the Capt. Krunch explaination of the Course finder tool. Both where very helpfull. I got more understanding from reading Angriffscheibe_Handbuch. Reading this gave me a better understanding of attacking and fingure out values of the attack(TB, AOB, etc...) Also want to give thanks to all who helped you. Now lets see if I can put it into action! The course finder I made is very crude, but it does the job.

You're welcome, and you are right, it was a team effort. Glad it was helpful. I am working on an updated version which should be out in a couple of weeks with more examples (I'm up to 18 now).

[klh]

Thanks for the work on this. I just completed my US Navy Is-Was and its Kriegsmarine equivalent. The templates and instuctions made the process relatively painless.

Respectfully Submitted;
CDR Resser

Congratulations. Don't forget to post a picture. It's fun to see other's workmanship and get some ideas.

[patton610]

this may seem silly, but I am building this as a aid for in-class presentation as part of a paper, and am unsure if all the plates are moveable or if certain ones are fixed to one another. I am particularly concerned about the two largest plates on the back-side. please help remedy my stupidity,
Thanks

[The Joker]

this may seem silly, but I am building this as a aid for in-class presentation as part of a paper, and am unsure if all the plates are moveable or if certain ones are fixed to one another. I am particularly concerned about the two largest plates on the back-side. please help remedy my stupidity,<br />
ThanksAll of the discs turn independently, for both tools. If you're making both tools you can fix them together, back-to-back by laminating the bottom disc of each tool together. Also, make sure that when you print the Attack Course Finder, that you print the C disc on transparency, NOT the P disc. The P disc goes right under the C disc. I mixed up the two the first time. If that doesn't make sense, I can post some pictures if you need me too.

[patton610]

Thanks I have everything done done except fastening the disc together. I terrified of missaligning the disc when I attach them. KLH said he used a drill, then a nut, bolt, and washers. the "time in minutes" disc and the very top two on the front are transparencies, the rest are laminated paper. I am a bit worried that a drill might melt some of it...and most, well all hole punches I have seen will not reach.

[don1reed]

I used an ice pick heated on the stove to burn/punch through. Worked like a charm. Caveat: go slow.

[Urge]

I used an awl, it has a sharp point so you can get it to penetrate right at the center of the X. I used round head fasteners(brass, 1 inch) from Staples to provide the axis/axle.

Urge

[sckallst]

Made myself an "is-was" yesterday using the great stuff from the Cap'n and Hitman and the advice of others contained in teh posts here. Used laminated cardstock for first three layers of the front side and the bottom two layers of the back side. Cut up the plastic overlay layer from an old poster frame for the transparent layers. Printed the periscope and 'time in minutes' layers on clear stickers, adhered them to the thin plastic and then laminated them as well.

Carfully lined everything up, put the holes in and assembled with a short nut and bolt forming the spindle/axis. Happy with the alignment, I disassembled. Cut a piece of foam poster board as a backing material, then glued the base layers of the front side to that and made a hole for the bolt. Trimmed the poster board to fit, aligned and glued the back side base to the poster board. Reassembled and put into action.

Pulled into Surabaya on Jan 2, 1942 and earned my first RFB 100% realism Silver Star.

Coincidence? I think not.;)

Only 'mistake' I made was failing to heed the advice of others and put a proper 'handle' on the 'enemy vessel' card to get around the issue of that card being the same size as teh scope. Easy enough to fix if I feel the need. Adding the posterboard 'sandwich' layer really gave the thing a tiny bit of heft and a good deal of sturdiness. Also, with the thicker middle layer, I'm able to use one of those spring type paper clips as a sort of clamp to keep the B layer 'locked in' so that it doesn't want to move around when I move the enemy or periscope layers.

Thanks again guys for the guidance and inspiration. For anybody wanting to take the plunge and make one of these, it's really pretty easy, and it's a satisfying little project to complete.

Question:

Can anybody better explain the use of the squares on the enemy card and ticks on the periscope card. I think I 'got' the first answer in the doumentation, but I'm having a hard time seeing exaclty how these things work. I'm pretty good at graphical plotting anyway, but I'd like to know more about how this thing works.

[jmr]

Can anybody better explain the use of the squares on the enemy card and ticks on the periscope card. I think I 'got' the first answer in the doumentation, but I'm having a hard time seeing exaclty how these things work. I'm pretty good at graphical plotting anyway, but I'd like to know more about how this thing works.

I'm a bit confused about the squares as well despite reading the example problem a few times over.

[joegrundman]

The squares are very simple - it's a way of making very quick distance estimates

assume you have the thing set up to represent the situation

http://img18.imageshack.us/img18/6353/picture7g.jpg (http://img18.imageshack.us/my.php?image=picture7g.jpg)

You take a range reading - let's say it's an easy number, 5000m.

you'll note that on the periscope layer there are 5 divisions between you and the target, so in our example each division represents 1000m

The shortest distance to target track is this distance here:

http://img14.imageshack.us/img14/8613/27976971.jpg (http://img14.imageshack.us/my.php?image=27976971.jpg)

you can see this is 3,500m given that each square represents 1000m

If you doing a normal intercept course (holding the target to a 90 degree bearing) the following shows the approximate distance

http://img6.imageshack.us/img6/7983/norm.jpg (http://img6.imageshack.us/my.php?image=norm.jpg)

which is about 5000m in this case

Remember, YOU assign the range value of each square to be convenient after you have your range reading.

Using this you can then calculate how far you need to move to be ready to strike the target

[berobispo]

I just printed and build my KM wiz wheel:DL. Trying your Passive Sonar Approach, joegrundman, I didn't work out how to adjust the observed change in bearing (after slowing down/accelerating) in the KM version. I have a version from KLH that has angle of bow on the outermost ring. On the middle ring there is range and speed. It does not have several bearing scales in the middle ring, as does your in-game version of the KM wiz-wheel. Is there a way to convert small degrees into the large 1-90° of my wiz-wheel or is there a new version that resembles the SCAF?

[Pisces]

The disks you see in the pictures of Joegrundman here above, are equivalent to the other side of your KM Attack disk. Except the KM disk does not have that square grid on it to judge distances graphically. The side you are talking about can only be used for multiplying/dividing angles, speeds, distances and times. The side in the images above only for manipulating (adding/subtracting) courses and (periscope-) bearings. They work completely different and those scales cannot be mixed. All you can do is memorize the number and locate it in the scale on the other side.

[Fish40]

I hate to dig up an ancient thread but the link for the speed determination side of this tool is dead. I have the course and AOB side. Does anyone have it?

[Jan Kyster]

06:00 in the morning and on the way to work :yawn: so it's just a quick and dirty pack... probably with dublets too :D

http://www.mediafire.com/file/bnmu8atv1lpaxal/Submarine_Attack_Course_Finder_Mix.zip

[Fish40]

Thanks bro, I really appreciate it:yeah:

[TG626]

Printable Manual

http://www.subsim.com/radioroom/downloads.php?do=file&id=4419

[TorpX]

Good Idea!

:yeah:

[skip]

Hi am looking to building one of these tools in the near future.

However am looking for advice on materials to use.

1. What thickness in microns for the various disks

2. What type of transparancies to use ie would acetate be ok and if so what thickness.

3. What thickness of laminate pocket to use 125 or 250

4. The most important how to fasten all the pieces together assuring that they will all turn easily

Really appreciate any and all help in this matter

Cheers

[TG626]

I used...

1 heavy paper.
2 overhead transparency in a laser printer
3 dunno, its a 3m product, one sheet is heavy plastic, the other a thinner plastic with adhesive.
4 a #6 bolt, fender washers, and 2 nuts with a split washer between them.

The bottom has the lamination used as intended, all others I only used the adhesive sheet covering the printed side. That includes the transparent sheets, both to protect the printing and to make the disk more rigid.

As a kid these things were all around the house (other circular slide rules that is) and they were made of anything from navy card stock to metal.... My grandfather was an engineer in the 1940s onward so we had slide rules as well as "data wheels" where you made a selection and read the answers from a window on the tool.

[skip]

Thanks for the help TG,

Would you be able to post / link all the relevant template files for both sides of the whiz wheel. Or any other slide rules that you may have the templates for that would make playing the game feel more "authentic" :)

Also is this wheel primarly for SH4, can I use it for SH5 too.

Many thanks

[Pisces]

http://www.hnsa.org/doc/attackfinder/index.htm

This link contains still valid download links to all the template files of the US Is-was Attack Course Finder on the hnsa.org site. Somewhere in there is also a photo of the original device. (only black on white, seems perfect in low-light conditions, considering) The first link in the first message of this thread is dead, and should have pointed to this. But somehow ended up linking to some Google Group and died in the process.

I also uploaded them in different packages (untouched, probably downloaded them back then from the now dead links) to my website:

Range/Speed/Sine/Time sliderule disk (rear side):
http://ricojansen.nl/downloads/Printable_IS-WAS.rar

Course/Bearing solver (front side)
http://ricojansen.nl/downloads/Submarine_Attack_Course_Finder_-_White.pdf

As an added bonus I still have a Shockwave file somebody made (don't know who, probably mentioned in this thread somewhere), with which you can play around with the Course/Bearing solver in your browser:

http://ricojansen.nl/downloads/iswasxc2.swf

Thanks for the help TG,


Also is this wheel primarly for SH4, can I use it for SH5 too.

Many thanksIt can be used with ANY game that is based on the proper mathematical rules and nautical concepts and units. It's only specific for SH4 in the sense that it (initially) focused on the US submarines. But could technically also be used in SH3 or SH2 (atleast the angle solver) and certainly SH1. I think Destroyer Command too worked with yards. It's just a replica of a mathematical device used in the real world back in those days. You just have to consider that the range scale is in yards. Speed in knots is standard among most games.

[in_vino_vomitus]

Big thanks for these. I'll get right on with making them :)

[in_vino_vomitus]

So. Have made the thing, with enough gear left over to make an onmimeter too - Thanks to everyone who took the time to make and upload these files - and thanks to Don and Hitman for this little gem, which is going to be extremely useful....

One last item from my corner:

Do the Math.

I observe thru the scope a Hakusika Maru: Aspect Ratio 4.6 from the book.

Aspect Ratio thru the scope:
4.25 tics high
13 tics long.

Do I break out my hh electronic calc ? No, I reach for the SACF/IW:

http://i77.photobucket.com/albums/j42/donhreed/sa1.jpg

Since the SACF is a cicurlar sliderule (logrithmic) with a sine scale:

As you can see, 25.1° falls beneath 4.25, the height of the target ship, so I then rotate the center disk to place the 25.1° mark under 13, dividing 4.24 into 13. The answer is read above the sine of 90° = 3.05, the observed Aspect Ratio.

http://i77.photobucket.com/albums/j42/donhreed/sa2.jpg

I can now proceed to compare the two AR's to obtain my Angle on the Bow with the SACF.

4.6 : 90° : : 3.05 : 42°

http://i77.photobucket.com/albums/j42/donhreed/sa3-1.jpg

Simple and fast


EDIT NOTE: Had to goto photobucket, ImageShack is having a bad day.

[in_vino_vomitus]

I have a feeling I won't be the first person to think of this, so all those for whom this is old hat, my apologies, however I found it useful and it doesn't seem to have been mentioned in the thread so far, so here goes.....

You can use the reverse side of the SACF to do simple TSD calculations by lining up the distance in yards with the time taken to travel it and reading the speed off the sine scale at the pointer; but lining the time and distance scales is dependent on a good eye, which I don't have. Anyway. it's a relatively simple matter to make another index pointer and mount it on top of the time scale/inner wheel, which is what I did. It's really useful for say getting speed by timing the target through the crosshairs, because all you need to do is use the floating index pointer you've just added, to line up target length and time taken, at which point the speed can be read off the inner wheel pointer.

I haven't tried it yet, but I imagine it would work just as well for points obtained from say, a radar plot, or active sonar maybe.

Anyway, like I say, I doubt it's an original idea, but it's handy and it doesn't get in the way and is worth considering, I think, for anyone planning to build one of these.

In lieu of a thousand word description, here's a photo. It's set up to show 117 yards in 25 seconds = 8.5 knots or thereabouts....

*Edit* Overstating the obvious, but because it's a logarithmic scale, this could just as well be saying that about 42 minutes at 8.4 kts will get you 11800 yards, or as close to it as makes no practical difference. Slide rules rock :)

https://farm4.staticflickr.com/3890/14840728013_84729ae87d_c.jpg

[BigWalleye]

I have a feeling I won't be the first person to think of this, so all those for whom this is old hat, my apologies, however I found it useful and it doesn't seem to have been mentioned in the thread so far, so here goes.....

You can use the reverse side of the SACF to do simple TSD calculations by lining up the distance in yards with the time taken to travel it and reading the speed off the sine scale at the pointer, but lining the time and distance scales is dependent on a good eye, which I don't have. Anyway. it's a relatively simple matter to make another index pointer and mount it on to of the time scale/inner wheel, which is what I did. It's really useful for say getting speed by timing the target through the crosshairs, because all you need to do is use the floating index pointer you've just added to line up target length and time taken, at which point the speed can be read off the inner wheel pointer.

I haven't tried it yet, but I imagine it would work just as well for points obtained from say a radar plot or active sonar maybe.

Anyway, like I say, I doubt it's an original idea, but it's handy and it doesn't get in the way and is worth considering, I think for anyone planning to build one of these.

In lieu of a thousand word description, here's a photo. It's set up to show 117 yards in 25 seconds - 8.5 knots or thereabouts....



Brilliant!

IVV, how do you fab the plastic parts and put the markings on them? What kind of stock do you use and where do you get it?

[in_vino_vomitus]

Brilliant!

IVV, how do you fab the plastic parts and put the markings on them? What kind of stock do you use and where do you get it?

The base is foam board, the transparent parts are printed on inkjet OHP transparencies and the other bits are printed on card. I used contact adhesive to stick several thicknesses of card together [after printing] for the moveable wheels - the bases get enough rigidity from the foam board. All the parts get laminated with self adhesive laminating film, but the transparencies get more - I think I gave them about five layers in all. I glued the first base scale to the board and then cut it to shape. I stuck a pin through the centre and used that as a guide for sticking the second base scale to the other side. Not everyone will find this as tricky as I did, but be aware that if you're using contact adhesive it grabs as soon as it touches - hence its name. I forgot this obvious point and ended up with the reverse scale at 45 degrees to the first. Not difficult to stick another one over it, but one does feel a bit of an idiot doing it :) A slower-drying adhesive might be better for that one operation.... My big problem was making the holes the same size and perfectly central. - I tried cutting them first and the result was OK - but not best. I ended up buying a cheap hole punch and dismantling it, then using one of the cutters to punch the centre holes. A nut and bolt holds it all together. pretty much everything came from the office supplies shop in the shopping centre.

It is brilliant - I wish I'd thought of it. Huge respect to everyone who did what it took to get this out of the museum and into my hot sweaty hands. Shame I'll never meet any of you in a bar - This is definitely worth beers :)

[razark]

I doubt it's an original idea, but it's handy and it doesn't get in the way and is worth considering, I think for anyone planning to build one of these.
As soon as I first made one, I saw the value in adding the extra cursor. I made a second, more sturdy one, and added it. Ever since then, I've wondered why it wasn't built in in the first place. Folks, if you're going to make one of these, add the extra cursor!

[in_vino_vomitus]

As soon as I first made one, I saw the value in adding the extra cursor. I made a second, more sturdy one, and added it. Ever since then, I've wondered why it wasn't built in in the first place. Folks, if you're going to make one of these, add the extra cursor!

I love the smell of vindication in the morning.... :)

[BigWalleye]

The base is foam board, the transparent parts are printed on inkjet OHP transparencies and the other bits are printed on card. I used contact adhesive to stick several thicknesses of card together [after printing] for the moveable wheels - the bases get enough rigidity from the foam board. All the parts get laminated with self adhesive laminating film, but the transparencies get more - I think I gave them about five layers in all. I glued the first base scale to the board and then cut it to shape. I stuck a pin through the centre and used that as a guide for sticking the second base scale to the other side. Not everyone will find this as tricky as I did, but be aware that if you're using contact adhesive it grabs as soon as it touches - hence its name. I forgot this obvious point and ended up with the reverse scale at 45 degrees to the first. Not difficult to stick another one over it, but one does feel a bit of an idiot doing it :) A slower-drying adhesive might be better for that one operation.... My big problem was making the holes the same size and perfectly central. - I tried cutting them first and the result was OK - but not best. I ended up buying a cheap hole punch and dismantling it, then using one of the cutters to punch the centre holes. A nut and bolt holds it all together. pretty much everything came from the office supplies shop in the shopping centre.

It is brilliant - I wish I'd thought of it. Huge respect to everyone who did what it took to get this out of the museum and into my hot sweaty hands. Shame I'll never meet any of you in a bar - This is definitely worth beers :)

Thanks, IVV. I used very similar techniques for mine. Except I could never figure out how to make the transparent parts. I tried printing on the heaviest transparency film I could buy, but the resulting pieces were just not stiff enough. (Let us consider the obvious remarks to have been posted, please, and just move on.) I tried to glue the film onto .040' transparent acrylic stock, but I used 3M spray adhesive, and the result was translucent, but not clear. I also tried printing on self-adhesive laminate, but ink-jet ink doesn't adhere to it. I never thought of using multiple layers of laminating material for support. And I make the opaque parts out of multiple layers of card stock. Just never made the connection! Thanks again! I'm going to get some laminating sheets and try it.

BTW, the other face of my wheel is Cap'n Scurvy's AOB Calculator. http://www.subsim.com/radioroom/downloads.php?do=file&id=3347. It doesn't have the little "bow" and "stern" protrusions. Instead, the zero bearing is prominently marked. That eliminates the alignment problem between the two faces.

I was concerned about accurately punching the center holes so the disks would align. Instead of using a nut and bolt for the pivot, I stack all the layers on a large carpet tack as I fab them. Then, after the last layer, I glop the protruding point of the tack with Crazy Glue and press a small (1/4") piece of thin foamcore onto the tack and down onto the topmost layer. Then I clip off the protruding point. It is easy to center all the layers on the tack, there is very little runout, and the CA grips the tack well enough to keep it anchored in place. I've used the wheel for about two years and it hasn't tried to come apart.

But now I'm going to have to make another one with transparent index disks!

[in_vino_vomitus]

I wish I'd thought of using a carpet tack. That sounds an order of magnitude better than punching a hole. Until I assembled the thing I had no idea the difference a slight misalignment would make....

[BigWalleye]

I wish I'd thought of using a carpet tack. That sounds an order of magnitude better than punching a hole. Until I assembled the thing I had no idea the difference a slight misalignment would make....

As you did, I had to figure out a way to make the thing. Some of my ideas worked well, others not so. At the time, I couldn't find a thread on the subject. There is one now!

A long time ago, I would periodically have to realign my slide rule. (Yeah, that's how old I am!) Amazing how little misalignment it takes to make 5x5 equal 24.8!:D

[CTU_Clay]

WOW! What a handy tool to have when playing our beloved Silent Hunter series of video games.

For a person like myself, old, and a bit handicapped with arthritis in both hands makes it difficult to make such a tool. (maybe a little lazy in my old age too. :har:)

Is there someone out there that could make me one?

I would be glad to pay the expense. PM me if you can be of help.

Shipping would be to the USA 77418 zip code.

Thanks

-Clay

:subsim:

[in_vino_vomitus]

As you did, I had to figure out a way to make the thing. Some of my ideas worked well, others not so. At the time, I couldn't find a thread on the subject. There is one now!

A long time ago, I would periodically have to realign my slide rule. (Yeah, that's how old I am!) Amazing how little misalignment it takes to make 5x5 equal 24.8!:D

I'm one of the slide rule generation too, although I've never had to adjust one. I can remember when calculators started to become available, and weren't allowed in class. I like using a slide rule though because it keeps you involved in the calculation in a way that punching numbers on a keypad doesn't. Also lets not forget that slide rules were good enough to get people to the moon and back....

[in_vino_vomitus]

WOW! What a handy tool to have when playing our beloved Silent Hunter series of video games.

For a person like myself, old, and a bit handicapped with arthritis in both hands makes it difficult to make such a tool. (maybe a little lazy in my old age too. :har:)

Is there someone out there that could make me one?

I would be glad to pay the expense. PM me if you can be of help.

Shipping would be to the USA 77418 zip code.

Thanks

-Clay

:subsim:

Yeah - My first attempt at making one of these is sitting in my desk drawer. I had a go at giving it away last week, without any luck. cover the cost of postage and a jiffy bag and you're welcome to it...

[CTU_Clay]

Yeah - My first attempt at making one of these is sitting in my desk drawer. I had a go at giving it away last week, without any luck. cover the cost of postage and a jiffy bag and you're welcome to it...

PM in transit to you.

-Clay

[skip]

Hello all

I finally got around to building my own SCAF from the provided download.

However even after reading the documentation I am struggling to understand how to use it.

The only use of it I have understood is the method for finding the AOB from the aspect ratio of the ships length/height.

Would be fantastic if anyone could post other practical uses of the SCAF with some easy to understand examples.


Many thanks

[CapnScurvy]

Hi skip, just wanted to point out that SCAF stands for "Ship Centered, Accuracy Fix"....a mod I made years ago to fix the inaccurate mast height measurements found in the Recognition Manual. Those measurements are directly used when taking a Stadimeter reading during game play. Some heights are off by several meters, which will return Range findings off by several 100 meters!

Although....... I've revised many height measurements to be more accurate (then SCAF) with the mod.....Optical Targeting Correction (http://www.subsim.com/radioroom/showthread.php?t=181172).

One thing I didn't count on during my SCAF making days was the fact that most of the subs don't have the Stadimeter/Periscope as the center point of measurement. This means my corrections with SCAF are good for one particular view bearing......but will be slightly off in another. OTC corrects this off center position, giving reasonably accurate measurements in all view bearings. Correcting not only for the Stadimeter, but also the periscope Telemeter Divisions too (those are the hash marks on the periscope lens).

You mention the length measurements, yet OTC is the only mod that provides length measurements in the Recognition Manual. It's with the accurate Telemeter Divisions scaled to the correct optical view that will provide a good estimate of AoB using only the periscope (as it would in real life).

My apologies for bringing this up in someone else's thread regarding an "Is-Was". However, back in 2007 I also made a similar devise and called it an AoB Calculator (http://www.subsim.com/radioroom/downloads.php?do=file&id=3347) (I never knew what an Is-Was was until after making my calculator). I only bring it up because you asked for "other practical uses", which you may find if you download and read "High Realism Tutorial (http://www.subsim.com/radioroom//downloads.php?do=file&id=907)".

[Able72]

Sorry for the Thread Necro, but I was looking for the .pdf files to make on of these for myself and the links seem to be down. Does anyone have the files for this?

[razark]

Sorry for the Thread Necro
Don't be sorry. This is a thread everyone should see.

Does anyone have the files for this?
You can find the files needed here, along with the manual for using it:
http://archive.hnsa.org/doc/attackfinder/index.htm


Note:
If you make one, consider adding an extra cursor to the is-was side. It comes in very useful.

[Able72]

Thank you.

Don't be sorry. This is a thread everyone should see.
Note:
If you make one, consider adding an extra cursor to the is-was side. It comes in very useful.

Please explain what you mean? Why, how is this useful? Multiple targets?

[razark]

It comes in useful if you're needing to keep a temporary result while doing your calculations. It also helps in lining up the inner time dial with the outer speed/range dial. There are also a couple methods you can use the wheel for that involve such things as comparing angles at different ranges. This becomes easier when you have the cursor to track and line up on one of the values, while you use the built in one for the other.

It's not strictly necessary, but it's so useful that I wonder why it wasn't built in.

[saintkas]

As I looked through the description of how to assemble one of the Submarine Attack Course Finder devices from the SubSim site I noticed a variance between what was described for the homemade version versus what is described in the SACF Mk I Mod 3 Manual.

In the manual in the section titled “Description, Course Finder on page 3 it reads:
"A" - Azimuth circle (base disc) represents own ship, for reading relative bearing with periscope pointer.
"B" Compass rose (middle disc) for reading compass course of own and enemy ship.
"C" - Enemy Card (top disc) represents enemy ship, for reading relative bearing on enemy bow and track angle.
Periscope pointers (placed between "B" and "C") represents line of sight, for reading bearings and courses.

According to this, the “P” disc of the SACF is placed between the “B” ring and the “C” ring.

In the description of how to assemble the rings on the SubSim site it says to put the “P” ring on top.
The issue is that putting it on top creates the necessity of adding a handle to the “C” ring so that it can be easily rotated. If the “P” ring is placed beneath the “C” ring as is described in the manual, the handle on the “P” ring protrudes out beyond the “C” ring which eliminates the need for modification to the “C” ring.

If you look closely at the photograph of the front of the SACF you can just tell that the “P” ring is indeed underneath the “C” ring.

Just thought it might be helpful to point this out.

If there are enough people interested in having these made, there are several companies that make all sorts of circular decision and reference devices who could be engaged to make them for us.


Fair winds and following seas!

[saintkas]

I was poking around at the International Slide Rule Museum website and came across a photo from WW II of 2 officers at the periscope and one was setting up a solution on an Is-Was. I got permission from the museum to share this photo on the forum.

I thought this should be here for the history of it.

[Front Runner]

....I found out why the A scale is reverse pretty quick :p It is meant to be read from the PERISCOPE layer (The transparent one with marks) and not from the own ship overlay of the A disk.

Example: A target is 45º to the right of your bow, and has an AOB of 60º port. You are heading 200º right now. Here's how to set up the wheel:

1.- Move the B ring (True course) until its 200º mark is at the bow of your own ship silhouette in ring A (Matching the 180º mark in the A ring)

2.- Move the Periscope transparent layer to the 45º mark of the A ring. (Here's the reason why it is reversed! To move your scope "right" means in fact moving in the opposite direction the lower part of that wheel, so that the upper shows the target with the correct AOB side)

3.- Last, set the estimated AOB of your target (60º port) in the B ring.

Result: Your target's true course is 105º:smug:, as you can now read in the B ring (True course ring)

Own ship is on course 200 degrees.
Target is on 45 degrees relative bearing.
Target has Port 60 degrees Angle on the bow (AOB)
Set this up on the SACF and see that target course is 105 degrees.

Link to operational shockwave SACF
http://ricojansen.nl/downloads/iswasxc2.swf

http://www.subsim.com/radioroom/picture.php?albumid=1190&pictureid=9999

[spugnoid]

For anyone interested (and yes, I've just necro'd this thread again), I've been working on a solitaire board game version of WWII sub warfare and decided to make a wheel to assist with plotting.

I've redrawn it based on Hitman's version and I'm posting a link to my Dropbox folder where you can grab it. If you find any problems with it (spelling etc.) let me know. It should print to 7.75in dia if you don't scale it. The last page has all the transparencies on one sheet so don't print them separately if you don't want to.

https://www.dropbox.com/sh/bcf7zkdqrw8orz5/AACV4syDCY98LeiYRV8y2_uja?dl=0

Cheers.

[Gauthier]

For anyone interested (and yes, I've just necro'd this thread again), I've been working on a solitaire board game version of WWII sub warfare and decided to make a wheel to assist with plotting.

I've redrawn it based on Hitman's version and I'm posting a link to my Dropbox folder where you can grab it. If you find any problems with it (spelling etc.) let me know. It should print to 7.75in dia if you don't scale it. The last page has all the transparencies on one sheet so don't print them separately if you don't want to.

https://www.dropbox.com/sh/bcf7zkdqrw8orz5/AACV4syDCY98LeiYRV8y2_uja?dl=0

Cheers.


Hello,


It would be nice to know your solo boardgame...
Tks a lot!

[Aktungbby]

Indeed, I'd like to print out his drop box site and make the gizmo errr banjo.

[Torpex77]

Thought this was interesting.))

https://maritime.org/doc/attackfinder/index.htm