Tactics against the convoy

[predavolk]

This could be pages of material. Briefly:

Early War - sneak in the gaps between the escorts at PD, running silent, in medium-heavy seas

Mid War - as above, heavy seas important

Late War - shoot from outside the convoy

XXI - load up on homing torps, ravage the escorts, sink the convoy unmolested

[Bosje]

surface attack at night, decks awash and slow speeds, creeping up on them between lead and flank escorts. firing 2 or 3 shots from around 3 km at 60 degree AoB, periscope depth while reloading 2 tubes and run straight into the convoy lanes as the first shots hit. you'll get another 4 or 5 shots (sterntube) off at decent angles from inside the convoy lanes before diving to safety.

not easy but potentially very rewarding, will work well up to 1941 at least. i had one successful surface attack as late as 1943 in rough seas, their radar is not 100% sure to get you

[Graf Paper]

So far, my usual method for attacking a convoy is to use the ruler to draw a baseline of their projected course and the protractor tool to mark a 90 deg. line to plot my interception point.

I set myself up a few km ahead, go to 40m depth and sit quiet while I mark my targets as they approach, trying to ID ships by their sound. I then nudge into the lanes and drift as the escorts pass by overhead.

Once the first few rows of merchies go past, I rise to periscope depth and start launching my torps, using my stern tube for the smaller ships that usually occupy the outer column behind me. I turn as needed to line up my targets, aiming for the boilers, one eel per target.

The idea there is to cripple as many ships as possible, forcing the bulk of the convoy to leave them behind. I go as deep as I can and try to evade and wait out the escorts until they have to leave to protect the convoy. Once the coast is more or less clear, I rise back to 14m and finish off the damaged ships with my reloads or deck gun, if seas permit.

Of course, that's not the only way I go after convoys but it's the method I use most often.

With my 13th patrol set to begin sometime in March 1941, I'm sure that a lot of tricks and tactics I've learned will need to be changed or replaced very soon.

[unterseemann]

I try to get ahead of the convoy on their supposed course, it's quite difficult sometimes as they often zig-zag (realism 100%, no map contact update).
Periscop depth, silent running and hydrophon check when i think it's good.
When i see the leading escort i try to guess the distance between my sub and the escort, usually around 8500m. So convoy is around 10.000m away but i can't usually see them at this moment. 10.000 m means that a 7kts convoy need around 45 min to do this distance. I start immediately to go to -155m depth at 3kts ( i think escorts can hear you if you make 4kts). It took 12 min to reach this depth with a type VIIB. As i need 22min to get back to periscop depth at 2 kts, i will spend 5 min at -155m at 2kts. During this manoeuver i try to keep leading escort in my 0 with the help of hydrophons and when i reach -45m i try to get perpendicular to the convoy route.
So when i get back to PD the convoy is near, and most of the time i'm in a very good position to attack. The last seconds before seeing the convoy are very exciting! Then i fire two salvos of two torpedoes for ships up to 5000tons or single shot for light targets.

This works in jun 41 with absolut calms seas (0 m/s), hope it helps!