We kept our boat at one of the marinas on Mobile Bay on and off for 18 months. We met a couple of house boaters in the 40-50 ft range who had come down the rivers and had decided their boat were not capable of handling the ICW from Mobile to Ft. Myers. Mobile Bay and the Big Bend can be less than pleasant. Boats were sold in Mobile to people taking them back up river. Don't remember the type of boats. Although large these both seemed like the flat houseboats one sees on the lakes up north. Different shape from the Bluewater houseboats. The Great Loop is a 6,000 mile trip with at least 3 or 4 open water stretches. If one is buying a new boat for the Great Loop, the trip justifies buying a boat that leaves some margin for error. You might also check with those who have done the trip on a 50+ ft boat. Unless you are doing a delivery schedule you will want to stop in a number of small marinas where the 50 footers must be put on a wall or cannot be accomodated. At 42 feet we have been locked out of a number of anchor sites where the suggested length was less than 42 feet. The trip can be made in any boat. It is just a question of enjoying the trip. Marty Campanella Bay Pelican KK42