[UKönig]

Nice work! You got pretty lucky.
As a surface combat vessel the U-boat is a washout. Hopelessly outclassed by virtually *all* of its opponents. Too low in the water, low lateral stability, visual range too short. Weapons awkward and cumbersome. Rate of fire too low. Too slow, both on the surface and under it. Still, it's a good feeling to accomplish something difficult and "fight above your weight" and win.
I have taken out armed trawlers with the deck gun. I think I even managed to score a few lucky long range shots against a corvette as it was approaching, so that by the time it got within 2km I was already the victor.
But as a general rule I do not fight above my weight class. I will take on surface vessels no bigger than a corvette, and only under specific circumstances, otherwise ...we go under. Attack from stealth, or just creep away and hope he doesn't notice or loses interest.