Thank you for your feedback. I know that the bug is annoying. As well as the user interface interaction is not very clear. But please consider that it was made within 72 hours and a lot of time went into graphics and balancing tests.
The highest level a player has reached yet was 23, as far as I know. The trick is to reassign the crew regularly. Also they will stop work when they´ve got hitten (which was more or less intended).
If you want a more polished version, follow me and stay up to date.
The 50 coins item is a stats upgrade. It will lead to more repairing power, more damage at the cannons and less damage taken while steering thru rough sea.