The Adventurer's Boat will come to your cooperative village twice a day. He always leaves at the same time but the time he takes to come back can be different depending on the damage the boat will have.

Each time the boat returns, there's a chance that it comes back damaged. It is required to send it back to the sea with 0% to keep damage at a minimal each time. If the boat is 100% damaged on one of the 3 parts (hull / stowage / cabin) when it leaves, the port will drop one level.