Manual Targeting Failure

Andrewsdad · 06-22-14, 02:32 PM

Just two anecdotes regarding two topics raised here.

Target sighted at high stbd angle on bow so I made a end-around approach. This allowed me to make a lot of measurements, including a good 10 minute apart measurement and using the nomograph, determined the tgt speed at 9.5 knots.

It was night and weather was 15 m/s wind with moderate visibility the periscope was difficult to use....

However I got set up for a 90 degree shot with a torpedo run of 700 meters.

Alas... periscope observation and mast-height measurement showed that the target would get pretty close to the arming distance so I needed to shoot early so the torp would arm for sure. So I switched to magnetic exploder and fired with a gyro angle of 320 degrees.

I used the external camera to watch the shot... The torp made the big turn and hit the target right on the bow. Almost a miss ahead !!! I figure that my failure to update the range to target at time of firing was why I almost missed !!! She sank in 10 minutes.

As to the time it takes a target to sink... I hit a tanker straggling from a convoy. Got her just aft the bridge structure. Again the wind/sea were running high. After two hours I put another into her, unfortunately it struck in almost the same place. No more internal torps and couldnt reload externals in the bad weather so I hung around waiting for her to sink or the weather to improve so I could use the deck gun.

"She's going down!" was reported 37 hours later !!!!!! At that point I departed the scene never seeing it actually sink.

One more just for fun.... Another straggler struggling in the heavy seas. End around approach. Target making 3.5 knots, Ideal setup. Observing thru the attack scope, tube #3 open, 15 more degrees to go when..... The crew starts to cheer and she sinks !!!!! A victim of King Neptune seconds before I was to fire !!!!

Ach du Lieber !!!!

AD

maillemaker · 06-23-14, 11:21 AM

The short answer is, if you shoot with a 000 gyro angle, range to target does not matter. All that matters is target speed and AOB.

However, a 90 degree AOB attack makes the chance of hit and good impact more likely.

Steve

Pisces · 06-23-14, 03:22 PM

Quote:

Originally Posted by maillemaker

The short answer is, ...

I don't care a bout TL/DR reponses.

vanjast · 06-26-14, 04:30 AM

Quote:

Originally Posted by Andrewsdad

I figure that my failure to update the range to target at time of firing was why I almost missed !!!
AD

You are correct... the TDC range setting is important for Close and Far range targets.
At medium ranges (approx 1500 - 3000m) you can get away with incorrect range settings... but it still effects accuracy if you are looking at 'sniping'.

Pisces · 06-26-14, 05:13 AM

With a gyro angle of 320, and the uboat perpendicular to the target track, it's apparent length does seem 25 percent shorter than if it got hit at gyro angle 0. So yeah, significant reduction in margin of error.The range dial could have made a difference. As the correction it makes is larger at short range compared to long range.

Andrewsdad · 06-29-14, 09:21 PM

I do believe it is a good habit for Kaleuns to always input range data into the firing solution even if it is a 90 degree shot.
Having a firing routine on a checklist will go a long way toward not missing when the action gets going !!!

Salute !!
AD

06-22-14, 02:32 PM	#1
Andrewsdad Machinist's Mate Join Date: May 2001 Posts: 130 Downloads: 81 Uploads: 0	Just two anecdotes regarding two topics raised here. Target sighted at high stbd angle on bow so I made a end-around approach. This allowed me to make a lot of measurements, including a good 10 minute apart measurement and using the nomograph, determined the tgt speed at 9.5 knots. It was night and weather was 15 m/s wind with moderate visibility the periscope was difficult to use.... However I got set up for a 90 degree shot with a torpedo run of 700 meters. Alas... periscope observation and mast-height measurement showed that the target would get pretty close to the arming distance so I needed to shoot early so the torp would arm for sure. So I switched to magnetic exploder and fired with a gyro angle of 320 degrees. I used the external camera to watch the shot... The torp made the big turn and hit the target right on the bow. Almost a miss ahead !!! I figure that my failure to update the range to target at time of firing was why I almost missed !!! She sank in 10 minutes. As to the time it takes a target to sink... I hit a tanker straggling from a convoy. Got her just aft the bridge structure. Again the wind/sea were running high. After two hours I put another into her, unfortunately it struck in almost the same place. No more internal torps and couldnt reload externals in the bad weather so I hung around waiting for her to sink or the weather to improve so I could use the deck gun. "She's going down!" was reported 37 hours later !!!!!! At that point I departed the scene never seeing it actually sink. One more just for fun.... Another straggler struggling in the heavy seas. End around approach. Target making 3.5 knots, Ideal setup. Observing thru the attack scope, tube #3 open, 15 more degrees to go when..... The crew starts to cheer and she sinks !!!!! A victim of King Neptune seconds before I was to fire !!!! Ach du Lieber !!!! AD

06-23-14, 11:21 AM	#2
maillemaker Sea Lord Join Date: Apr 2007 Posts: 1,639 Downloads: 75 Uploads: 0	The short answer is, if you shoot with a 000 gyro angle, range to target does not matter. All that matters is target speed and AOB. However, a 90 degree AOB attack makes the chance of hit and good impact more likely. Steve

06-26-14, 05:13 AM	#5
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	With a gyro angle of 320, and the uboat perpendicular to the target track, it's apparent length does seem 25 percent shorter than if it got hit at gyro angle 0. So yeah, significant reduction in margin of error.The range dial could have made a difference. As the correction it makes is larger at short range compared to long range.

06-29-14, 09:21 PM	#6
Andrewsdad Machinist's Mate Join Date: May 2001 Posts: 130 Downloads: 81 Uploads: 0	I do believe it is a good habit for Kaleuns to always input range data into the firing solution even if it is a 90 degree shot. Having a firing routine on a checklist will go a long way toward not missing when the action gets going !!! Salute !! AD