There is as association for people who are or will cruise
the great loop called the Great Loop Cruisers Association. www.greatloop.org
. I have read their newsletters and from what I can see the majority of members who do the great loop have powerboats ranging from 35-feet to about 48-feet, with many between 40 and 45 feet. Most are trawler-types like Mainship, Grand Banks
, Albin etc., but there are plenty of people who do it in express style powerboats. Pilothouse single-screw powerboats like the American Tug 34 and the Nordic
Tug 37 and 42 are also popular. People who do the loop in power catamarans like the PDQ
34 or Endeavour
powercats seem to be pleased with their boats.
One design feature to look for is ease of access around the decks -- when you are handling lines in locks it is safer and more manageable if you can move around the decks easily.
There is another group that has a blog site for Great Loop enthusiasts -- you may be able to find it at Samurai Hosting