He has been identified as 43-year-old Weston Lucas of South Dennis, New Jersey.
The discovery was made around 3:00 a.m. Monday at a marina where the boat was docked, located on the 700 block of N Rhode Island Avenue.
Police and medic crews were called to that scene after the body was found.
It was determined the cause of death to be of natural, medical causes (ruptured aorta).