I really like this system of repairs.
Some short thoughts:
* - I still think the crew need to be looked at, repairing crew to 100% is terrible.
* - I would even be happy with a mix of repair kits that are popped in battle that repair 10% of a certain item (hull, sails) and are limited to 2 of each type and the survival mode repairs mentioned in the OP.
* - If sinking is going to be much more difficult than other conditions for ending a battle need to exist to end a battle. Right now, its Spike > dps until sunk.