I always under estimate the speed using the RAOBF
 

I'm close to being sent back to Kiel to face the wrath of the big D himself as I just can't get the target speed correct when using the RAOBF and am looking for guidance please.

My process using TWOS mod:

• I correctly identify the ship - even use the external camera to view it close up #cheating.com
• Find the length in metres
• Time how long it takes to go past my vert periscope line from bow to stern (at the water line, not the top of the bow/stern)
• Rotate the middle disk of the RAOBF so that the time in seconds (outer numbers) is under the length in metres
• Arrggh, it's all gone wrong and if I wasn't a mild-mannered, sensible, middle aged man, I'd be having a rage fit.

Example from tonight. T2 Tanker. Length 150m, took two minutes 31 seconds to move past the vertical line. This gave me a speed of 2 knots which seems very slow.

I then measure the speed using distance over time and it comes in at 6 knots which gave me a two torpedo hit and one dud so must have been pretty close to correct with my 90 AOB attack.

I've watched this video: so many times now to ensure I'm not being an idiot. Maybe I am. Please send help.

https://youtu.be/jBFlosUt8SY

Can anyone shed any light on this?

Would a video of me recording ship length and time help?

Do you put the target on 0/180 bearing while timing it?

No but I am stopped, albeit probably still drifting at 1-2kts. Let me try again at 0/180.

Thanks.

Heds

This reminds me of the old Groucho Marx line while playing a doctor; Groucho: "Does it hurt when you do that ?"
Patient: "Yes"
Groucho: "Then don't do that". :)
Learn the historical fast 90 attack method and forget all these gadgets that others besides you the commander would have been doing irl. :)
p.s. i.e., coming to a complete stop was not done irl.

A few things to keep in mind with the wheel…

1) you must identify the ship correctly. If you do not and the length is off, you will have issues.

2) if the ship is approaching you at an acute angle, you will have a bad solution… the more perpendicular the angel the better.

Thanks everyone.

I will try again when I get some time to play.

BTW I def had the ship ID correct as I was using the external camera with the game paused and went through the book methodically and the ship was identical to the picture.

That will throw you off in the speed calculation if you are looking sideways from yourself. Even what looks like a little bit of speed, if you are moving only 30 degrees to the line, you drag it sideways by halve of your speed. So 2 knots become 1 knot. Still significant. If you move, make sure you are turned towards or away from it. When you move along the line then it stays fixed. If you move to an angle of the line than you are dragging the line sideways and keep moving the finish line for target.

Also make sure you are not looking at it too bow-on. You need to clearly see the point of the bow, and the end (usually marked by a flag), to know when to time it. I don't know why the video presenter tells you to wait for where the water meets the bow. With a sloped bow it would depend on the weight and draft how long it would be along the waterline. Maybe it is constant, maybe a mod changes that level. Who knows. It is the extreme length that maters, that is what is in the recognition manual.

As for the RAOBF, I guess that is ok. I am not familiar with this particular mod, or have not played SH5 at all much. But I did invent this mark for calculating speed way back in SH3 days for the OneLifeCrisis GUI. Some mods have it in different places because of their own particular zoom levels and optical scale size. If you are using the exact same mod as in this video then you can rely on it. (As it proved to be the right one in this)

I cannot in anyway figure out how you came to this with the RAOBF tool. You must be doing this technique wrong. Length is the most outer scale, time is along the distance scale against it. Speed is read from the inside scale on the movable ring at the upper-right red marker. (All red-markers on it rely on the inside edge of that moveable ring, NOT the outer edge as look suggestive with the alignment of the end of it.)

Can you show a screenshot of the actual RAOBF when you try this out the next time, and it fails? As you would come out at about 9.4 knots for 150m in 31 seconds.

Ahh, exactly the opposite! Length on the outside, time on the inside.