Targeting a ship from behind while chasing it

skirich · 08-25-19, 05:08 PM

How complex is the calculation for targeting a ship from behind while you chase it?

Assume the ship doesn’t know I am coming up behind and is traveling at a high rate.

I assume it can be done but I have to calculate the running speed to get the distance or do I just use maximum range on the torpedo and hope it catches up to it?

What about launching a torpedo while moving? Bad?

fireftr18 · 08-25-19, 06:25 PM

I won't unless it's a slow moving ship. If I can, I'll maneuver around so that I can target the side. If it's fast moving, I won't bother.

cdrsubron7 · 08-25-19, 06:41 PM

........an "up the kilt" shot. It's something I never attempt unless it was last resort. Also hope the ship doesn't zig after you fire.

08-26-19, 01:02 PM

<What about launching a torpedo while moving?>

Can be done. However, the game does not account for maximum speed with an extended periscope, which was probably 5 to 6 knots due to vibration and potential damage.

An undamaged, fleeing ship would almost always out run a WWII sub chasing submerged at a max speed of 8 or 9 knots. You could travel on the surface and make up the distance differential only if the target is unarmed or you're out of visual range. The task is called "End Around" where you want to pass the target at a substantial, unobserved (radial) distance to put you in front of the moving target. You then submerge and wait until the target travels across your bow.

<How complex is the calculation for targeting a ship from behind while you chase it?>

Not complex for the Target Data Computer if one inputs the correct variables for bearing & distance and angle on the bow & target speed; and the target does NOT increase or decrease speed and makes NO adjustments to direction of travel. That said, the problem is the lack of torpedo speed and max distance of travel. The distance and time to overtake the target is always increasing. Thus, a slight change of target speed and/or direction of travel will create a significant miss.

Just my humble opinion.

KaleunMarco · 08-26-19, 03:19 PM

Quote:

Originally Posted by skirich

How complex is the calculation for targeting a ship from behind while you chase it?

Assume the ship doesn’t know I am coming up behind and is traveling at a high rate.

I assume it can be done but I have to calculate the running speed to get the distance or do I just use maximum range on the torpedo and hope it catches up to it?

What about launching a torpedo while moving? Bad?

chasing a ship is not a normally a worthwhile effort.
the best method to sink a ship that is ahead of you and moving away is to quickly compute whether you can allow the ship to move out of visual range so you can surface and increase your speed such that you can remain out of visual range, pass the target-ship on a favorable course and then submerge in a favorable position for a torpedo attack.
always assume that your enemy is armed and will resist your efforts to make a surface attack.
yes, it is that complicated.
so...you have to ask yourself the question: is that ship important enough for me to spend time and fuel to get in front of her and try another shot?
only a commander on the scene can make that decision.
good luck. and good hunting.

jimmbbo · 08-26-19, 04:44 PM

Hmm... lots of things going the wrong way...

narrow target
moving away
torpedo relative speed reduced by up to half
close in launch required to keep within torps' range if fast target.
how to position the sub to get the shot in the first place, other than being submerged as the merchant is overhead AND on the sub's heading...

Reckon that's why I've never tried it, but whatever floats your boat...

Pisces · 08-27-19, 10:58 AM

Well, he can measure the speed rougly by the change in distance over time. Range is however not easy to measure accurately by the scope.

But firing torpedoes from such a position is very disadvantageous. You want to hit them in their broad side, not on their most slender silhouette.

So yeah, no! The end-around is more effective to get bang-for-buck.

Mios 4Me · 08-27-19, 09:31 PM

Even with automatic targeting and Mk 16 torpedoes, up-the-kilt shots are low enough probability that I take them only when necessary: almost never with merchants over 2km and only under 1.2 km for retreating warships of CA size or less. BBs and CVs are such high value targets that I'll almost always take the shot under 3km, especially the Yamatos.

If firing while moving at high speed, it's prudent to allow a few extra seconds for the TDC solution to stabilize.

08-25-19, 05:08 PM	#1
skirich Chief Join Date: Aug 2019 Location: Patroling the south pacific Posts: 321 Downloads: 75 Uploads: 0	Targeting a ship from behind while chasing it How complex is the calculation for targeting a ship from behind while you chase it? Assume the ship doesn’t know I am coming up behind and is traveling at a high rate. I assume it can be done but I have to calculate the running speed to get the distance or do I just use maximum range on the torpedo and hope it catches up to it? What about launching a torpedo while moving? Bad?

08-25-19, 06:25 PM	#2
fireftr18 Ocean Warrior Join Date: Feb 2010 Location: Kentucky Posts: 2,526 Downloads: 77 Uploads: 0	I won't unless it's a slow moving ship. If I can, I'll maneuver around so that I can target the side. If it's fast moving, I won't bother. __________________ Of all the forms of Martial Arts, Karaoke causes the most pain!

08-25-19, 06:41 PM	#3
cdrsubron7 Sink'em All Join Date: Mar 2001 Location: Naperville, IL Posts: 2,150 Downloads: 305 Uploads: 1	........an "up the kilt" shot. It's something I never attempt unless it was last resort. Also hope the ship doesn't zig after you fire. __________________ Head Deep and Keep'em Astern" - LtCDR Samuel D Dealy SHIV Guide \| Imperial Japanese Navy \| US Submarines

08-26-19, 01:02 PM	#4
von Zelda Stowaway Posts: n/a Downloads: Uploads:	<What about launching a torpedo while moving?> Can be done. However, the game does not account for maximum speed with an extended periscope, which was probably 5 to 6 knots due to vibration and potential damage. An undamaged, fleeing ship would almost always out run a WWII sub chasing submerged at a max speed of 8 or 9 knots. You could travel on the surface and make up the distance differential only if the target is unarmed or you're out of visual range. The task is called "End Around" where you want to pass the target at a substantial, unobserved (radial) distance to put you in front of the moving target. You then submerge and wait until the target travels across your bow. <How complex is the calculation for targeting a ship from behind while you chase it?> Not complex for the Target Data Computer if one inputs the correct variables for bearing & distance and angle on the bow & target speed; and the target does NOT increase or decrease speed and makes NO adjustments to direction of travel. That said, the problem is the lack of torpedo speed and max distance of travel. The distance and time to overtake the target is always increasing. Thus, a slight change of target speed and/or direction of travel will create a significant miss. Just my humble opinion. Last edited by von Zelda; 08-26-19 at 01:16 PM.

08-26-19, 04:44 PM	#6
jimmbbo Run silent, run deep Join Date: Jun 2016 Posts: 225 Downloads: 59 Uploads: 0	Hmm... lots of things going the wrong way... narrow target moving away torpedo relative speed reduced by up to half close in launch required to keep within torps' range if fast target. how to position the sub to get the shot in the first place, other than being submerged as the merchant is overhead AND on the sub's heading... Reckon that's why I've never tried it, but whatever floats your boat...

08-27-19, 10:58 AM	#7
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,892 Downloads: 300 Uploads: 0	Well, he can measure the speed rougly by the change in distance over time. Range is however not easy to measure accurately by the scope. But firing torpedoes from such a position is very disadvantageous. You want to hit them in their broad side, not on their most slender silhouette. So yeah, no! The end-around is more effective to get bang-for-buck. __________________ My site downloads: https://ricojansen.nl/downloads

08-27-19, 09:31 PM	#8
Mios 4Me Sonar Guy Join Date: Feb 2019 Posts: 394 Downloads: 38 Uploads: 0	Even with automatic targeting and Mk 16 torpedoes, up-the-kilt shots are low enough probability that I take them only when necessary: almost never with merchants over 2km and only under 1.2 km for retreating warships of CA size or less. BBs and CVs are such high value targets that I'll almost always take the shot under 3km, especially the Yamatos. If firing while moving at high speed, it's prudent to allow a few extra seconds for the TDC solution to stabilize.