rules. You will need a copy of the rules, or at least general agreement among the players as to the version of the rules which will be in effect. The rules are easy enough to learn that a complete novice will become competent in less than half a bottle of wine.
The game takes only enough room to throw the dice - it can be played on any boat that has a flat surface - say the dinette table, or I suppose in a pinch, the floor could be pressed into service. It is perfect for a boat - virtually any boat.
Next time you have folks aboard, you should try it!