Convoy Attack Technique

[Joefour]

Hi Guys,

I am submitting this post for criticism, constructive or otherwise.
I have done this a few times and figured it was time to get other peoples' input. I haven't seen this method in the manuals, nor in any of the past threads, so if someone has done this before please quote chapter and verse so I can go have a look at it.
This is the method I have developed for a convoy attack:
One caveat:I would NOT attempt this if the convoy has any flanking escorts on the side of the convoy closest to you. You can try it but you are really rolling the dice.
Second caveat: Don't use this method if the convoy's speed is faster than what you can do at flank speed while submerged.

First:Get as close as possible without being detected, either at periscope depth or with decks awash. That's a no-brainer, of course. Pick out a target, or targets as the situation allows. Then pick out what I call a "cover ship", preferably a big fat noisy cargo ship inside the convoy and IN FRONT OF your target(s). Just make sure your cover ship isn't carrying racks in back, if you get my drift. This might be a little difficult if you are attacking at night. especially if there is no moon. Fire off your torpedos at your targets and immediately head for your cover ship at flank speed, diving as quickly as possible to 25-30M. Just make sure you will be below the cover's draft with some room for safety.
Now this is where it gets a little tricky. Just as your about fire and then dive, mark the position and course of your cover ship. It will make it a bit easier with the hydrophone readout. The goal is to get directly underneath or just behind your "cover", keeping the hydrophone "tail" as short as possible. If you can hear the racket of the propeller and engine loud and clear just above your head you know you are in a good position. Your own noise is masked by the ship above you. Now using the hydrophone graphic, match course for course and knot for knot with the cover ship above you. This might be a bit difficult since once your torpedos have found their mark, everyone will be zigzagging like crazy. That's why it's better to use a ship inside the convoy rather than one of the outer ones.
The escorts will be running around with searchlights and lighting off star shells, looking everywhere except where you're at. Keep this up, until things calm back down, the zigzagging stops, and the escorts' positions look like they are back to guarding the flock rather than looking around out in left field for a sub that ain't there.
When you feel it's safe, rig for silent running and slink away. Surface at a safe distance and flank ahead of the convoy and repeat the dirty business as desired.

Does this sound legit? If not, feel free to dump on me. I have tried this with both SH3 stock and GWX, with good results. It sure beats hell out of getting D/C'd for hours.

It was kind of eerie. A couple of nights after I decided to write this post, I flipped on a Netflix Instant comedy with Kelsey Grammer called "Down Periscope". I thought it was going to be another loser, but actually enjoyed it, in spite of the usual gags like farting in a crowded submarine while at depth. Anyways, there is one scene where he is involved in a war game (rigged against him) and he and his crew infiltrate Norfolk, VA harbor following just behind a super tanker, using its propeller cavitations to mask their own noise from the other guys. Sent some chills up my back.

[Cybermat47]

Sounds like a good tactic. I might see if it'll work in SH5... or if I'm skilled enough to pull it off.

[Joefour]

I had tried swimming with the convoy at periscope depth to stay out of the way of asdic, keeping my scope down and using the hydrophone only, but when they started crapping bricks and zigzagging all over the place, I was getting the hell beat out of my Turm when they bumped into me. So this ocurred to me one day, and it worked. The other thing is that the escorts are not fond of dumping D/Cs in the middle of the group; they'd be defeating their purpose and sinking their own freighters way too often.

I must admit that it's a lot easier in stock SH3 because the escorts "tails" are painted red. It's a lot easier to keep track of them.

[GJO]

Hiding in the convoy works fine in the early years of the game but once the merchants are armed and the escorts become more determined (from 1943 on) it is likely to prove fatal because the hunters will find and destroy you at all costs!

[Pisces]

I'm not sure if the prop-noise of the "cover ship" hides your own. (In reality it would probably) I fear the SH3 stealth model isn't so sophisticated. Any escorts are probably staying away because they don't want to collide with the "cover ship". Their ASDIC and hydrophone should still pick you up.

Also, going for halve an hour or more at flank-speed submerged is a pretty heavy drain on your batteries. Going deep and then slow seems more economical. With better protection/advanced warning against a stray depthcharge. But maybe not later in the war.

[Paulebaer1979]

Originally Posted by Pisces

I'm not sure if the prop-noise of the "cover ship" hides your own. (In reality it would probably) I fear the SH3 stealth model isn't so sophisticated. Any escorts are probably staying away because they don't want to collide with the "cover ship". Their ASDIC and hydrophone should still pick you up.

Yes. Normaly engines of cargo ships are much louder than engines of subs (even at flank). But i´m not sure, if this is coded in SH3.

Originally Posted by Pisces

Also, going for halve an hour or more at flank-speed submerged is a pretty heavy drain on your batteries. Going deep and then slow seems more economical. With better protection/advanced warning against a stray depthcharge. But maybe not later in the war.

Yes. Deep and slow is better.

Hiding under a cover ship makes sense, if you know the draft of the other ships around you, so you can launch your torps submerged. But that needs a lot of paperwork by hand for plotting courses and postions.

[banryu79]

Intresting technique, I will surely try it the next time I get a convoy under my hands (still in 1939, early war, second patrol).

I also think about a little variant of your technique: after you hide under the baffles and match course/speed with your cover ship, instead of navigating in this way for the next half and hour or so, slowly and steadly increse depth till near maximum depth while slowly decrese speed till silent running, eventualy going for all stop while listentning on hydrophone and waiting for the whole mess to go away...

[maillemaker]

I have used enemy ships as cover many times but I'm pretty sure the escorts always knew I was there. They just keep their distance to avoid hitting the merchant. This works really well with a Type XXI when you can slalom around and under ships of the convoy as you pick and choose targets. At 15+ knots the escorts can't keep up with you in the pack.

In fact, I have parked in shallow water next to a sunk-and-bottomed ship before and let the destroyer circle me - they won't drive in for fear of hitting the wreck. I then shoot at them as they cross my bow or stern tubes. Sometimes it even worked.

Steve

[Paulebaer1979]

Originally Posted by maillemaker

In fact, I have parked in shallow water next to a sunk-and-bottomed ship before and let the destroyer circle me - they won't drive in for fear of hitting the wreck. I then shoot at them as they cross my bow or stern tubes. Sometimes it even worked.

Nice idea. But i always hunt in deep waters - so i´m not able to try this.

[banryu79]

Originally Posted by maillemaker

In fact, I have parked in shallow water next to a sunk-and-bottomed ship before and let the destroyer circle me - they won't drive in for fear of hitting the wreck. I then shoot at them as they cross my bow or stern tubes. Sometimes it even worked.

I'm no expert but shouldn't the destroyer try to take you out by gun fire, if he knows were you are and you are shallow? (in RL, I mean)

[Joefour]

Originally Posted by GJO

Hiding in the convoy works fine in the early years of the game but once the merchants are armed and the escorts become more determined (from 1943 on) it is likely to prove fatal because the hunters will find and destroy you at all costs!

How many of the armed merchants would be equipped with hydrophones?
I do this with the hydrophone only, with periscope DOWN. And, to be honest, I'm still operating in 1941. Haven't gotten to '43 yet.

[Joefour]

Originally Posted by banryu79

Intresting technique, I will surely try it the next time I get a convoy under my hands (still in 1939, early war, second patrol).

I also think about a little variant of your technique: after you hide under the baffles and match course/speed with your cover ship, instead of navigating in this way for the next half and hour or so, slowly and steadly increse depth till near maximum depth while slowly decrese speed till silent running, eventualy going for all stop while listentning on hydrophone and waiting for the whole mess to go away...

That might work too. But my main object after the attack is to wait until the escorts stop looking for me. If you were to slowly sink down lower and wait, there is the possibility of them picking you up with a ping and echo.

[Joefour]

Originally Posted by Pisces

I'm not sure if the prop-noise of the "cover ship" hides your own. (In reality it would probably) I fear the SH3 stealth model isn't so sophisticated. Any escorts are probably staying away because they don't want to collide with the "cover ship". Their ASDIC and hydrophone should still pick you up.

Also, going for halve an hour or more at flank-speed submerged is a pretty heavy drain on your batteries. Going deep and then slow seems more economical. With better protection/advanced warning against a stray depthcharge. But maybe not later in the war.

That's why I don't even get near the convoy unless my batteries are 100% charged up. Something I should have done but didn't was to time how long it takes for the convoy to settle back down into it's routine. I do remember the meter getting pretty low. I have noticed that in almost all of the convoys there seems to be one escort that is persistant for awhile after the others have given up and moved on. But in that case it's a lot slimmer chance of one escort finding you than if 3 or 4 are hunting you.

[maillemaker]

I'm no expert but shouldn't the destroyer try to take you out by gun fire, if he knows were you are and you are shallow? (in RL, I mean)

Yes, it is a totally unrealistic situation. Presumably they would just run past the wreck and depth charge the crap out of it. Or ram me.

Steve

[banryu79]

Originally Posted by Joefour

I have noticed that in almost all of the convoys there seems to be one escort that is persistant for awhile after the others have given up and moved on. But in that case it's a lot slimmer chance of one escort finding you than if 3 or 4 are hunting you.

Yes. I think that (again, in RL) the tactical objective of that lone escort was to force the uboote to stay down, while the rest of the convoy fly away