long night
Earlier today my ships (Blackbeard Ketch) hit points were reduced to zero and she started sinking. Out of curiosity I opened my ships inventory and clicked a blue combat repair kit - to my surprise it started repairing the ship, and it stopped sinking.
I was able to sail to a nearby island with my bow pitched down about 40 degrees and completely underwater.
I replicated this twice, I will attempt to provide video after I get home from work.