Advice for later war campaigns
 

I have been playing a lot in 1939-1940 and having a lot of success, but I have found that if I try to start a career in later years, I tend to get destroyed pretty quickly.

I know the increased ASW capabilities of the Allies are realistic, so I am not complaining. I was just wondering if any more experienced Kaleuns might share some knowledge about how to survive in later war years. I don't seem to be able to get into position to attack convoys in 1942 and later very often, without being at least chased off (and and worst sunk).

I try to attack at night on the surface when possible, but I must admit I often use the noob technique of getting in front, going down to 80-100m, and either all stop or 1 kt, and let them come to me. This is fine in early years for the most part (so long as I time my ascent to PD correctly) but I'm getting creamed in later years.

When I have attacked at night on the surface in later years, always from the side of the convoy, I tend to get detected a lot. I guess it's because of their radar?

That's very likely the case. You need to have an exact idea of what your target is doing and then approach far enough away on the surface so you don't get detected. Then you submerge and approach for the final attack. This is actually very similar to your current strategy, just a bit more refined.

Example:

You spot a convoy. Estimate speed and heading as much as possible. IRL Kaleuns frequently used a method called "Ausdampfen". For this method you try to match speed and course of your target, i.e. you configure your boat in such a way that the bearing of your target remains constant. This method takes some time, but is very precise.

Once you have established a reasonably accurate target track you pull ahead at full speed. Once you're about 6-7 nm ahead of the target you turn in towards the track at maybe a 45° angle, still at full speed. About 1 nm from the track you turn on an opposite but parallel course to your target and then submerge and keep approaching at slow ahead at PD. About 2 nm before you meet the target go to ahead 1/3 still submerged and turn your boat in to the convoy, s.t. your bow points exactly to the track. Slow down again to 1-2 kts. Then wait for the targets to show up in front of your boat and torpedo them.

Another method that gives you a very good solution is to cross the target's bow. Once you reach 0° AOB, that is you look exactly at the target's bow from straight ahead of the target you plot a long straight line from your boat on the bearing of the target. This gives you the target's track.

Of course as I said, you always need to keep a safe distance from your targets and if they are escorted that distance may easily be 10-12 km. I think it was called 'nibbling at the horizon'. Sometimes only the smoke plumes of your targets may be visible. You can only close in once you have a reasonably accurate solution and you need to be silent in order not to get detected too soon.

Once radar hits the scene, not much can be done. One thing to try is to attack from further out.

4k meters or so. Don't expect early war/pre-radar results in late war/radar attacks.
Not going to happen. Be happy if you just get away. Hitting a ship is a bonus.

OK, that's about what I figured. Thanks.