Convoy Attack Tactics

[RushTheBus]

Hey everyone,

I'm having a bit of difficulty chasing and attacking large convoys in and around British coastal waters. Generally i find it difficult to determine the best orientation for my boat (especially when I'm chasing down a reported convoy) and how best to approach the situation (do i launch a spread for 4 torpedoes into the convoy or do i target individual ships).

Maybe its going a bit over board, but I'm going to start doing some research into convoy attack tactics and see if any of that information proves successful in game.

How does everyone else approach the situation?

[GoldenRivet]

Generally i follow the convoy's left or right flank at the outter edge of visual range with hyrdrophone checks every few hours to make sure they have not changed course which they will do frequently over the span of a few days in game.

when night time approaches i will accelerate ahead of the convoy and wait for them to near within visual range.

at this point i can see where the ships are, where the escorts are, what their search patterns are etc.

now, i will either remain surfaced or submerge to periscope depth depending on which year of the war it is because surfaced attacks will not succeed when the enemy is radar equipped. if submerged - silent running will help avoid detection of nearby escorts so long as you remain at ahead slow or stopped and do not get to near the escorts

using the scope (or UZO if surfaced) i will target individual ships, if my range is close enough i will used magnetic triggers set to approximately one - two meters running depth under the keel of the target ship (keel depth is available in the target ID book), but with shots over 1000m i do not consider this to be an option due to the habit of mag triggers detonating prematurely and strictly stick to impact triggers.

firing a salvo of 4 into a convoy will almost universally guarantee you to miss the ships

once i have scored hits i dive deep and steer for the tail end of the convoy and put distance between myself and the convoy so i can eventually surface and repeat the entire process.

a good convoy stalk and attack with multiple attacks can take 3 or 4 days in game while you slowly pick the convoy to pieces.

[BigWalleye]

Hey everyone,

I'm having a bit of difficulty chasing and attacking large convoys in and around British coastal waters. Generally i find it difficult to determine the best orientation for my boat (especially when I'm chasing down a reported convoy) and how best to approach the situation (do i launch a spread for 4 torpedoes into the convoy or do i target individual ships).

Maybe its going a bit over board, but I'm going to start doing some research into convoy attack tactics and see if any of that information proves successful in game.

How does everyone else approach the situation?

Reading about what was actually done in the RL boats is always worthwhile. If a game is worth anything (and SH3 is) then you should be able to apply real-world tactics. If not, IMO the game is crap.

From my reading, however, I believe that what you are going to find is that RL Kaleuns used a variety of tactics, all with success. If it works for you, then it works.

A good place to start your reading might be here:

http://maritime.org/doc/uboat/index.htm#par391

The Submarine Commander's Handbook, the KM's view of how they wanted their commanders to do it. (Not necessarily what they did....:))

[sublynx]

Playing NYGM late 1942

Radar, so keeping contact with hydrophone until the permission to attack is given.

I seem to do ok by getting into the front sector of the convoy. Radar, so submerged approach. Only 4 escorts, and the port and starboard guards make very large search patterns to the sides of the convoy - I get inside the convoy easily (getting out might be very tricky).

Three torpedoes to try to insure two hits. One just in front of the target, one in the middle, one just behind the target. One will miss, but might hit another ship behind the target. The fourth against a suitable target. Then turn towards the escape route, shoot the stern torpedo if I manage to turn into a good direction fast enough.

I try to stay at periscope depth to see what's happening and to have a good idea on how to best evade the escorts. 1 - 2 knots speed is not enough. I go faster in order to gain distance to the escorts coming in to investigate. When they get close I go back to 1 - 2 knots.

Pre-radar, pretty much the same, but faster and on surface. Shoot from longer range to make sure I can escape surfaced.

1943, I'll be using more magnetic pistols, FAT torpedoes, and eventually acoustic torpedoes. With acoustics I might try to take an escort out to gain a free side to attack from. But by 1943 I'll probably not be attacking convoys as the airplanes in NYGM seem to damage me or get very close every other or third attack. When they get bigger bombs, I'm dead meat. The Hurricanes would have killed me already, if the bombs weren't minuscule.

I have now managed to gain two wolfpack attacks in my career. If I get a wolfpack and the weather is very rough, I might save torpedoes and try to attack when the weather is better. So far I've attacked despite the weather, but the torpedo malfunction rate is horrendous.

Oh, and I never attack when it's shallow. If I manage to live until 1944, BdU will order me to do that. I'm not looking forward to that.

[RushTheBus]

Thanks for the comments / thoughts / links everyone.

I play with GWX & DEF at the moment and its October 1939. Got permission to head toward a reported large convoy heading east (toward England) in BF15 (my patrol grid if BF14). So i headed at full ahead to catch up, but the weather is garbage (wind 15m/s w/ high seas). I may just shadow them for some time to see if things improve.

What do you guys think?

[Zosimus]

Attacking convoys is the really enjoyable part of the game. Targeting single ships is kind of boring. It's just too easy because you never have to run silent and you can race under water at full speed to get into position.

I could give lots of tips for convoy attacks, but generally tactics that work like gangbusters at one visibility are ineffective at others. I'll give my approach for 9 km visibility and then you'll have to modify it for other visibilities.

My goal is always to get inside the convoy with a large ship in front of me for a two-torpedo salvo, with another large ship behind for an aft shot (again, two-torpedo salvo). To do that you first need the speed and exact course of the convoy.

The speed is usually pretty easy as many times the contact update gives you the exact convoy speed and a general idea of the course. If you can get close enough to get a look at the ships, then the course is as easy as drawing a line through them... that's rarely off by more than 3 degrees. If you can safety watch them for a long time, you can drop an x on one, wait about 15 minutes, and draw a line through those. That's spot on accurate... until they change course.

Your goal is generally to reach firing approach in 1.5-2 hours. Draw a line through your target and then use your compass or ruler to mark where the target is supposed to be in 1.5 hours. For example, if he's going at 8 knots, measure 12.0 and write down the time he's supposed to be there. Then draw a circle from there at 7.0 and you want to be somewhere on that circle in 1h30m from now. The ideal point can be figured out by drawing his speed along the line, (for example 0.8) and your speed perpendicular (0.2, which represents your underwater speed while running silent). A line drawn through the starting point to the intersect with the 7.0 circle lets you know the perfect spot.

Assuming the sea is calm, you should have no difficulty reaching that spot. I usually run 20km away from my target and then move into position. Once I'm there, I can go perpendicular to the target, dive, and move into position at 2 knots.

Of course sometimes you get there, dive, and the hydrophone is all quiet. That means the convoy changed course. Go to 25m depth, all stop, and man the hydrophone yourself. Then you can usually hear something in some direction. Go full speed in that direction for 20 km and then dive again and you'll usually reacquire the convoy and have to start all over.

Once you are 1 km away from the estimated intercept point, go to 1 knot and you should be about 500-600 m from your target when you fire. I use two torpedoes, 5º spread, 3-5 m depth (depending on weather), impact. If you are using map contacts and zoom in enough on your map, you should be able to see the approximate size of the ships you're firing at. I just fire at the biggest ones I can find and then figure out what they are when they sink.

I try to fire at the one in front of me, then fire at the one behind me, acquire a third target, and change course toward it. When your torpedos impact, that target should zig and if it zigs away from you, you'll have a perfect third shot. Then go as deep as you can and pray that the escorts don't ping you.

[ReallyDedPoet]

GWX has a section on this in their manual.

Plus a search for some older threads will also give you some
helpful info :yep:

[Tupolev]

The first half of this link is instrumental in intercepting convoys from a distance:

http://www.subsim.com/radioroom/showthread.php?t=88961

I usually dive just prior to intercept to attain sound contact and ascertain a more accurate bearing on the convoy.

After gaining visual contact, be it night or daytime, speed discipline is of the utmost importance. Followed very closely by maintaining a narrow aspect-ratio to the nearest escort (keep the bow/stern pointed at it). You can get a lot closer to an escort if you're going slow than if you're screaming away at flank speed. I try to stay under 8kts, less than 6kts if I'm showing my broadside. Obviously, planning an intercept that places you ahead of the convoy is best.

I also try to keep the convoy between me and the moonlight, but I'm not sure how well this is handled by the sim.

After nightfall, or even after the moon sets, I close to within visual range of the convoy proper from ahead of the port/starboard beam of the convoy. How close is usually a factor of sea/wind conditions, cloud cover, & visibility. Obviously some situations are more beneficial to remain unseen, but the only true way of discovering how close you can get is just by experience.

I wait until one of the escorts starts its outer patrol sweep, and at low speed proceed to close to firing range on the convoy. I tend to fire when the closest target is 2,000-2500m and nearly always from 90 AOB. If the sea is calm and I've been able to ascertain accurate firing data (find & run parallel course and match speed) then I'll firing off 4 individual shots on 4 individual ships. Otherwise, its a 2-spread on 2 targets. If I can get the boat turned around in time, maybe I'll get off a stern shot. 90% of the time I try that, though, its a miss.

I depart the area as quickly as I dare (again not more than 8kts) keeping the nearest escort on my stern.

Keeping a slow speed and presenting a small silhouette are the keys on surface actions. You've gotta position yourself well before commencing an attack. In that way, its actually very similar to submerged attacks. Before radar, you'd be amazed just how close you can get to an escort if you're careful.

T

[Scarredclown]

Last night i did my first convoy attack, at periscope depth, i sneak into the convoy, spot a big ship (ammo cargo). Shoot him twice with torpedo, try one at another ship not too far away. The cargo goes down with the first torpedo, i missed the second. I dive at 80 meters to evade, i do a bit of sharp turn to evade, but some depth charge hit me pretty good. I start to sink and nothing i do stop me from going all the way down.

What i've done wrong ? In escaping, i should i steer for the tail of the convoy ?

[Zosimus]

You should set a waypoint far ahead of the convoy on its path. Then when you start to dive, just return to course and you will probably duck under the ships in front of you. It can be very hard for a destroyer to depth charge you if you're directly under a cargo ship.

Eighty meters deep seems awful shallow to me. How deep was the water?

[Scarredclown]

You should set a waypoint far ahead of the convoy on its path. Then when you start to dive, just return to course and you will probably duck under the ships in front of you. It can be very hard for a destroyer to depth charge you if you're directly under a cargo ship.

Eighty meters deep seems awful shallow to me. How deep was the water?

it was over 350 meters. Thats what killed me. A depth charge flood a section and i just go down from there.

[Tupolev]

I usually take the boat down to 180m whenever I'm being depth charged. Depth will help keep you alive, at least before 1943.

If you've not been detected yet, try to depart the area in a straight line to put as much distance as you can between you and the destroyers. Try to stay as quiet as you can; 2kts or less and silent running will help.

If you're getting depth charged, wait until he loses ASDIC contact (the pinging stops) then crank flank speed and change course. After the explosions stop, try to put that destroyer on your stern. You're harder to ping with ASDIC with a small target showing.

If you've got more than 1 destroyer overhead actively depth charging you…Well, go deeper and pray.

T

[Zosimus]

I just took U-514 down to 205 meters. There were no strange noises, no leaks, and no problems. I maintained that depth for 10 minutes, then surfaced.

[maillemaker]

Lots of good advice already.

The trick to attacking a convoy is to get in front of it and let it run you over. You don't want to be exactly in front of it or the lead escort will pick you up. But 3000 meters off to one side or the other is ideal. Basically, you want to be inside the flank escorts and off to the side of the lead escort. Then run your boat perpendicular to the convoy.

You will definitely want to target individual ships. Random Hail Mary shots will not buy you much until you have pattern-running torpedoes, and even then hits are not likely.

However, by 1944, you may find that the only way you can attack convoys at all is from stand-off range of 5000 or more meters. You still want to aim at actual targets though.

If possible, you can get a "stack up" of ships arrayed in front of you so that if you miss the first ship you might hit the one behind it. This is good if you are not certain of the target speed.

Steve

[Tupolev]

Speaking of…

FATs are just about available in my career. Having never made it this far (alive) does anyone have any recommendations on the best way to set these up?

Do I want the turns to be in the direction of my target's travel, or do I want the turns to be in the direction of the convoy body?

T

[maillemaker]

It depends.

If you want them to continue to have a go at the same target (or line of targets), then I will turn them to follow the course of the convoy.

If you are shooting at the front of the convoy and want to have a shot at bagging ships coming up from behind, turn them towards the rear of the convoy.

You can adjust the leg length depending on how many ships are on either side of your intended target. If there are many columns of ships, a longer leg might bag some of them. But the longer the legs the quicker your fish runs out of gas before making much headway up or down the heading, especially if you fired from far away.

Honestly I don't give FAT setup a whole lot of thought during the attack, as things are happening too fast for me to be able to choose very tactical settings for them. I'm more focused on getting a good straight-run hit.

As a result, I'd bet FATs have only gotten me an unintentional hit maybe less than 5% of the time. Probably less than 3%.

Now acoustic homing torpedoes, on the other hand...they are magical in SH3. You can completely strip a convoy of its escorts with them. A wolfpack fully armed with those would have been a disaster for convoys.

Steve

[Zosimus]

What depth do you set them at? I can easily see shooting them at a destroyer, purposely setting the speed a bit low, knowing that the torpedo will turn and climb right up the destroyer's rear for a devastating explosion just under the stern.

[Sittingwolf]

Guys, excuse me, how actually acoustic homing work?

During my GWX campaign, long time ago, I was lucky to live till really very early 44 (January :D). I always relied on T-IIIs for stealthy actions and I never got to try acoustic homing :hmmm: Thanks.

[UKönig]

The type 5 acoustical homing torpedo was developed to combat the increased effectiveness of the destroyer escorts and hunter-killer groups.
4 holes in the front of the warhead had microphone pickups which would allow the torpedo to 'hear' the sound of the screws or even auxiliary machinery and turn in the appropriate direction (of the loudest sound it could pick up), until 'contact' was made.
In short, Lt. Werner "iron coffins", page 160-161 says...
The motorship (I was observing from) increased her speed sharply. In a few minutes, I could see a greenish iridescent light in the dark waters, rapidly coming towards us. Our ship turned to port, the light followed. We turned to starboard, the light stayed with us. The luminous (dummy) torpedo came closer still. The ship went into a wild zig-zag motion to escape the homing weapon. But the light in the sea followed diligently, reducing distance, then suddenly, dashed below the stern. That was when the warhead would have detonated, but in our case, the dummy torpedo with the luminous head continued on its track, shot ahead of us, and attacked our ship a second time. Then it passed below the keel, executed a long loop, repeated its snake like patterns and made yet another pass before its batteries were exhausted. Then it surfaced like a dead fish, its bright headlight glowing in the black water...
The escort killer torpedo was outfitted with homing sensors that guided it towards the sounds of a ship's propeller, or, if it was motionless, to the sounds of its auxiliary machinery. It was enough to launch the thing in the general direction of the target, the torpedo found its own way from there, no matter how violently a vessel tried to evade.
Unfortunately for the Germans, it was the Canadians who quickly (within hours of being introduced to the new weapon) developed countermeasures, in the form of 'foxers'. A rattler bouy trailed some distance behind the warship which would make more noise than the propellers, and thus, be the first thing the acoustical seeker found.

[Zosimus]

CATs (Counter-Acoustic Torpedoes) developed by the Canadians, and copied by the Americans under the FXR or "Foxer" program were effective against the Zaunkönig (hereinafter called GNATs for the German Navy Acoustic Torpedo) only because the majority of the time U-boats fired at onrushing destroyers (usually blindly) counting on the GNATs to home in on the propellers and then U-boats were ordered to dive, so the exact success or failure of the GNATs were unknown and unmeasurable.

Foxers drew the GNATs, definitely, and usually the GNATs would endlessly circle the Foxer device or blow up astern of the ship.

However, if the GNATs were fired from behind the destroyer, the Foxers drew the GNATs in for a pass under the Foxer, and on to the propellers of the escort, which was blown to pieces.

Later the US Navy developed Fanfare, which substantially improved on the FXR design.

[bstanko6]

Number one tip I can give you. early in the war, attack on the surface at night! Do this! Do this often! it works. Just today I took on two Auxiliary Cruisers with a DD escort at around 2030 hrs, clear sky no waves. Got in close about 1200 meters, killed the engines, and drifted well in around 800 meters, fired all four eels, hit the trailing Aux, missed the first, spun around and hit the first with the stern eel. Took off before the DD sent up the star shells! I was never even seen once. I even considered taking on the DD with the deck gun, but I was no where near my mission area, and did not want to sacrifice hull integrity.
And when you depart from the area, keep the escorts at your stern, do not show them your broadside as the could see you. show them as little of you as possible.

This is a great tactic. If you come across a convoy, stalk it til night fall, and I mean night, not dusk. You wont make it!