Generally, the amount of damage sustained is going to depend on which vessel does the ramming. Submarines in general had a considerable length of bow that was free flooding forward of the pressure hull, so if she rammed a surface ship much of the damage would be 'cosmetic." Likewise, surface ships are built with a collision bulkhead some distance abaft the bow to preserve water-tight integrity in the event of a collision. In a somewhat (but not much) more recent incident, when the smaller Stockholm collided with the Andrea Doria, the Stockholm sustained considerable damage to her bow, but the collision bulkhead remained intact and the ship stayed afloat. With a big hole in her side, Andrea Doria sank.

If a sub rams a destroyer, the sub will probably survive and there's a good chance the destroyer won't. If it's the other way around, the result would most likely be reversed.

J.T. McDaniel