I imagine the party boat is in constant use.
Aruban authorities wouldn't want to interfere with the tourist business to search a popular tourist attraction, now, would they?
Seriously, Steve Gregory Croes would not have been able to take this boat out after hours--it's not his boat. He just works on it as a deejay.
Friends of Croes, however, have said he is friendly with many of the fisherman who have their boats and huts in the same area (as the Tattoo). It wouldn't be hard for him to get ahold of a small fishing boat to take a body out to the North Shore, where all the sharks are.
If you needed to get rid of something like a body on an island who would you call? I'm thinking the friend who knows where to get a boat.