Game Bug?

[K-61]

You're definitely not playing with a more realistic mod like GWX. The stock game makes surface combat between U-boats and escorts an arcade experience. In real life, no U-boat ever sunk a destroyer with gunfire. A destroyer, frigate or corvette had at least one main gun and many other smaller caliber weapons, like AA guns and even handheld guns. They would open up on a surfaced U-boat with everything they had and any U-boat crewmen touching a gun were the first priority. The decks were raked with gunfire and the only way of surviving a sinking U-boat was to dive into the water.

GWX makes surface combat much more realistic. The U-boat was a terrible gun platform, rocking back and forth and making accurate aiming problematic. A larger vessel like an escort was more stable and thus enjoyed greater accuracy and rates of fire.

Ramming was a primitve but effective tactic. It was difficult to kill a U-boat with depth charges alone. A surfaced U-boat could potentially submerge at any time and thus be harder again to kill. Ramming it was an immediate means of killing it or making it unable to dive. U-boats ramming other ships? A U-boat's hull was much more fragile than a surface vessel's and since it needed to retain its integrity in order to dive, ramming was not an option for a U-boat commander. That vaunted net cutter would crumple very easily against a destroyer's hull and likely damage the U-boat's hull; it was soon done away with as it was a failure at cutting nets.