I have my hesitations about convoy attacks as well. Sometimes it does feel like it's not worth it, especially since you'll likely only hit one or two ships maximum at a time, and then spend four hours being depth charged by four destroyers.
BUT--If you figure the likelihood of destroyers finding you at deep depths is very low, especially at silent running and if you're usuing evasive manuevering, those two ships you got could be well over 10,000 tons a piece that's 20,000 tons in just two ships. Now figure you evade those escorts, skirt the convoy and ambush again, and sink another two ships, and you can see how attacking a convoy pays off.
Also figure into the equation that you also damage ships...and they become stragglers. Then when the escorts take off again, you surface and deck gun the wounded down.
I hate the escorts...they really are a pain in every Kaleun's arse, but in the end with proper tactics that can be found here, you can make short work of evading them.
My most successful patrol only netted me 28K tons, and that was just in one hit of a convoy in water only 110 meters deep. Granted it was in 1940, but if I can evade destroyers in shallow water, any one should be able to net 50K+ tons!
My tactics are to intercept the convoy's route, putting myself ahead of them in an ambush position, slink in deep at silent running right underneath the escort screen, and come up to 'scope depth in the middle of the convoy...find your juicy targets (big freighters, tankers, carriers ect.) launch your eels at them, go deep and turn an opposite direction from the convoy, and those escorts will lose you. When the escorts break off to rejoin the convoy, come back and pick off the wounded or the stragglers, then reintercept. Rinse repeat sort of deal.
I'll admit that single unescorted merchants make me squeal like a little girl, but the true tonnage lies with the risks of escorted convoys.
I guess you kind of have to be a thrill seeker.
