Originally Posted by treerat
If it holds charge and you don't have an issue when left on land it's unlikely to be the wording unless you have wires that are shorting out with e boat movement.
Or being wet? i.e. a current path created from say a deck fitting through water to the engine leg and back to battery earth. High water resistance so low current so fuse doesn't blow but over several days the current drains the batty...
As suggested you need to see if amps are moving out the batty or not. If not its the batty, is so you need to stop them moving!