Target Speed using Authentic measurement setting

Raven Morpheus · 09-22-16, 06:02 PM

Hey all

I decided to pick up SHIV again, along with SHV, and I recently came across the formula for quickly calculating target speed by measuring how long it takes a ship to cross your periscope crosshair.

I.e. time from bow to stern crossing periscope center line, then divide ship length in meters by time taken and then multiply by 1.94 (or 2 for a quicker, but rough, calculation).

But that only works for meters, and I use the Authentic setting for measurements, so I'm guessing I need to know the formula for US feet/yards - would I use the same formula but substitute meters for yards?

Can anyone help me out with that?

Thanks in advance

THEBERBSTER · 09-22-16, 06:30 PM

Hi RM
This would be easy to do if you had the ships length.
1 foot per second = 0.5925 knots.
Unfortunately SH4 does not show that information in the recognition manual.
Peter

razark · 09-22-16, 07:47 PM

Plot target position on map.
Wait three minutes.
Plot target position on map.
Measure the distance he's traveled in yards.
Divide by 100.

You now know his speed in knots.
You also have his course/AoB.

And as a bonus, you'll soon have Rockin Robbins to explain in detail why timing the crossing was not a valid method to figure speed.

Edit:
Or check here for the most recent targeting discussion.

And welcome back to the Pacific!

Gray Lensman · 09-22-16, 07:58 PM

razark's method above is the one I use for speed calculations but if you insist:

Here's a cutout from one of ColonelSandersLite's images regarding ships lengths.

Image5.jpg

For more information see post#11 here!

And even more from ColonelSandersLite here!
A worthwhile thread to read even if you decide to use the 3 minute rule above

Hope this helps

Raven Morpheus · 09-22-16, 08:21 PM

Ah, thanks guys, I forgot that the RM doesn't have lengths in it.

I do have the printed RM that comes with the SH4 collectors edition, I gave up on making my own as it was going to cost me too much, instead I caved and ponied up £20 for a 2nd hand copy of SH4 CE.

Might not help me with additional ships added by mods though, especially as I'm running TMO...

But it's a start.

Apparently though CapnScurvy's Optical Targeting Correction mod has a RM with lengths, and it's compatible with TMO. I'll be checking that out.

There is a scale bar underneath each ship picture in the RM (although on mine in 1080p it's shifted to the right and hangs off the end), but it doesn't say what length each segment of the scale bar is supposed to be. Dividing the known lengths of ships by the number of segments to get a scale doesn't help either - The Mogami has 5 segments on the bar, 200/5 is 40. The Yamato has 6 segments on the bar, 263.2/6 is 43.9. So you can't work out what scale the bar is at!

razark · 09-22-16, 08:30 PM

Gray Lensman, those are some good links. I've never seen them before.

09-22-16, 06:30 PM	#2
THEBERBSTER Growing Old Disgracefully Join Date: Dec 2012 Location: Dibden Purlieu - Southampton Posts: 9,605 Downloads: 1123 Uploads: 0	Hi RM This would be easy to do if you had the ships length. 1 foot per second = 0.5925 knots. Unfortunately SH4 does not show that information in the recognition manual. Peter __________________ LSH3-2015 <> TUTORIALS <> ALL YOU NEED TO KNOW <> ALL IN ONE PLACE SH4 <> TUTORIALS <> HOW TO DO IT <> INFORMATION <> DOWNLOAD LINKS SH5 <> TUTORIALS <> HOW TO DO IT <> INFORMATION <> DOWNLOAD LINKS Always Here To Help A Fellow 'Subber' \| Need An Answer to A Question Just Send Me A PM

09-22-16, 07:47 PM	#3
razark Ocean Warrior Join Date: Mar 2007 Location: Houston, TX Posts: 2,725 Downloads: 393 Uploads: 12	Plot target position on map. Wait three minutes. Plot target position on map. Measure the distance he's traveled in yards. Divide by 100. You now know his speed in knots. You also have his course/AoB. And as a bonus, you'll soon have Rockin Robbins to explain in detail why timing the crossing was not a valid method to figure speed. Edit: Or check here for the most recent targeting discussion. And welcome back to the Pacific! __________________ "Never ask a World War II history buff for a 'final solution' to your problem!"

09-22-16, 07:58 PM	#4
Gray Lensman Frogman Join Date: Feb 2007 Location: USA Posts: 308 Downloads: 104 Uploads: 0	razark's method above is the one I use for speed calculations but if you insist: Here's a cutout from one of ColonelSandersLite's images regarding ships lengths. Image5.jpg For more information see post#11 here! And even more from ColonelSandersLite here! A worthwhile thread to read even if you decide to use the 3 minute rule above Hope this helps __________________ . Member since February 2007 Wargaming since 1971 (1st game Avalon Hill's Stalingrad) Hobby/Gaming Computng since 1977 (TRS-80) (adhoc programming & game modding ever since)

09-22-16, 08:21 PM	#5
Raven Morpheus Machinist's Mate Join Date: Aug 2012 Posts: 125 Downloads: 143 Uploads: 0	Ah, thanks guys, I forgot that the RM doesn't have lengths in it. I do have the printed RM that comes with the SH4 collectors edition, I gave up on making my own as it was going to cost me too much, instead I caved and ponied up £20 for a 2nd hand copy of SH4 CE. Might not help me with additional ships added by mods though, especially as I'm running TMO... But it's a start. Apparently though CapnScurvy's Optical Targeting Correction mod has a RM with lengths, and it's compatible with TMO. I'll be checking that out. There is a scale bar underneath each ship picture in the RM (although on mine in 1080p it's shifted to the right and hangs off the end), but it doesn't say what length each segment of the scale bar is supposed to be. Dividing the known lengths of ships by the number of segments to get a scale doesn't help either - The Mogami has 5 segments on the bar, 200/5 is 40. The Yamato has 6 segments on the bar, 263.2/6 is 43.9. So you can't work out what scale the bar is at! Last edited by Raven Morpheus; 09-22-16 at 10:03 PM.

09-22-16, 08:30 PM	#6
razark Ocean Warrior Join Date: Mar 2007 Location: Houston, TX Posts: 2,725 Downloads: 393 Uploads: 12	Gray Lensman, those are some good links. I've never seen them before. __________________ "Never ask a World War II history buff for a 'final solution' to your problem!"

09-22-16, 06:02 PM	#1
Raven Morpheus Machinist's Mate Join Date: Aug 2012 Posts: 125 Downloads: 143 Uploads: 0	Target Speed using Authentic measurement setting Hey all I decided to pick up SHIV again, along with SHV, and I recently came across the formula for quickly calculating target speed by measuring how long it takes a ship to cross your periscope crosshair. I.e. time from bow to stern crossing periscope center line, then divide ship length in meters by time taken and then multiply by 1.94 (or 2 for a quicker, but rough, calculation). But that only works for meters, and I use the Authentic setting for measurements, so I'm guessing I need to know the formula for US feet/yards - would I use the same formula but substitute meters for yards? Can anyone help me out with that? Thanks in advance Last edited by Raven Morpheus; 09-22-16 at 06:27 PM.