Okay, so I should've known the answer to this, and just called out the falsehood right then and there, but I had someone join our ship today and he claimed that after three cannon hits to the same spot on the ship, the hole will be permanently enlarged, as in water floods in at the fastest rate if the hole springs again (even after repaired with a plank).
He claimed that because of this mechanic, we were at a disadvantage having been in numerous fights even though our ship was fully boarded back up.
In all my two years of sailing, I have never heard of this, or really checked if this was true. It's something which "feels" true since it sounds realistic, but I think this would have been brought up before due to the balance concerns.
Can someone put my mind at ease that this guy was full of it? Or am I just that oblivious to how the game works after all this time?