SUBSIM Radio Room Forums - View Single Post - "Snap Shot" -- to answer your question Johnfb

Alfred Keitzer · 01-29-12, 06:35 PM

Arg!!! I had written a rather lengthy reply to you question and when I went to post, Hitman had just closed your topic. So now you get the short answer.

First off, with TDC ON, misha1967 provided some very good input. He is right, AOB and Target Speed are the two most important ingrediants for the solution. Range not so much, but I must forgo that discussion for now. Here's the quick and dirty for a 90-AOB "snap shot" with TDC speed set to zero. Good to about 30-35 degrees off the nose or tail (stern torpedoes) -- beyond that, torpedo straight run comes in play (more lead required). Also note this is for approximately 90-AOB. Anything else, the sine of the AOB comes into play.

The 90-AOB "snap shot" with TDC ZERO SPEED SET --

1. Go to Attack Map and turn TDC OFF

The little button marked "1" and "0"; "0" is TDC OFF

2. Set Target Speed to Zero on TDC

Very important -- now torpedo run is determined by periscope look angle after you ...

3. Turn TDC back ON.

Very important -- TDC must be ON to feed periscope look angle to the torpedo

4. Estimate Target Speed

Slow Convoy -- 6 kts
Medium Speed Convoy -- 9 kts
Fast Convoy -- 13 kts
-- or -- better yet, best to get a good target speed from observation and know ahead of time.

5. Select torpedo and torpedo speed

6. Calculate Lead

SLOW speed torpedo lead = 2 x Estimated Target Speed
MEDIUM speed torpedo lead = 1.5 x Estimated Target Speed
FAST speed torpedo lead = 1.3 x Estimated Target Speed

7. Open torpedo door to eliminate launch lag

8. Lead the center of the target by the lead angle computed in step (6.) above with your periscope

9. Fire

For each subsequent torpedo, open torpedo door first, lead target with periscope, and fire.

Don't forget to turn TDC back ON after you set the Target Speed to zero.

Sorry, I would explain how I got all this but I gotta run for now.

01-29-12, 06:35 PM	#1
Alfred Keitzer Kapitän zur See Join Date: Jun 2007 Location: San Diego, CA Posts: 93 Downloads: 264 Uploads: 0	"Snap Shot" -- to answer your question Johnfb Arg!!! I had written a rather lengthy reply to you question and when I went to post, Hitman had just closed your topic. So now you get the short answer. First off, with TDC ON, misha1967 provided some very good input. He is right, AOB and Target Speed are the two most important ingrediants for the solution. Range not so much, but I must forgo that discussion for now. Here's the quick and dirty for a 90-AOB "snap shot" with TDC speed set to zero. Good to about 30-35 degrees off the nose or tail (stern torpedoes) -- beyond that, torpedo straight run comes in play (more lead required). Also note this is for approximately 90-AOB. Anything else, the sine of the AOB comes into play. The 90-AOB "snap shot" with TDC ZERO SPEED SET -- 1. Go to Attack Map and turn TDC OFF The little button marked "1" and "0"; "0" is TDC OFF 2. Set Target Speed to Zero on TDC Very important -- now torpedo run is determined by periscope look angle after you ... 3. Turn TDC back ON. Very important -- TDC must be ON to feed periscope look angle to the torpedo 4. Estimate Target Speed Slow Convoy -- 6 kts Medium Speed Convoy -- 9 kts Fast Convoy -- 13 kts -- or -- better yet, best to get a good target speed from observation and know ahead of time. 5. Select torpedo and torpedo speed 6. Calculate Lead SLOW speed torpedo lead = 2 x Estimated Target Speed MEDIUM speed torpedo lead = 1.5 x Estimated Target Speed FAST speed torpedo lead = 1.3 x Estimated Target Speed 7. Open torpedo door to eliminate launch lag 8. Lead the center of the target by the lead angle computed in step (6.) above with your periscope 9. Fire For each subsequent torpedo, open torpedo door first, lead target with periscope, and fire. Don't forget to turn TDC back ON after you set the Target Speed to zero. Sorry, I would explain how I got all this but I gotta run for now. Last edited by Alfred Keitzer; 02-01-12 at 01:53 AM.