As long as there are at least two casters aboard ship: elven pirate hunter, they can all shift concentration of spells affecting the ship or the weather between themselves as a bonus action. A caster who is concentrating on more than one such spell at a time must not move or take any actions (except to shift concentration to another caster), as doing so will end concentration on all spells. If they are injured or other wise required to make a concentration check, they must make separate saves for each spell they are concentrating on.

Whenever ship: elven pirate hunter starts its turn with 50 hit points or fewer, it is actively sinking and must make DC 10 Constitution saves every turn. If ship: elven pirate hunter has 0 hit points, it automatically fails its saving throws to avoid sinking. On a failed save, one of the ships decks is completely filled with water. If all the decks are filled, the ship has sunk and drops to 0 hit points.

Repairing the ship so that it has more than 50 hit points stops the checks or saves but does not remove any water. If at least half of ship: elven pirate hunters’s minimum crew spend an action bailing over two turns, they can restore a ship’s deck. Some magics may be able to remove water from a deck, at the DM’s discretion.

Magical druidic protections mean that ship: elven pirate hunter can ignore the effects of stormy weather as long as it is taking no actions besides Dash actions.