Try this link:
http://www.ultimategetaway.net/
As Stone mentioned, this boat goes to the Dry Tortugas from Fort Meyers. They do a 4 day / 3 night trip that gives you 2 full days of diving (up to 8 dive sites in a day - you pick the ones you want to dive) in the Dry Tortugas and two dives in the Gulf of Mexico on the way home. The diving in the Dry Tortugas is pretty good, although I didn't find the reefs to be as pristine as they are reputed to be. The final dive of the trip is an air force relay tower in the Gulf. It lies in 110 feet of water. Every square milimeter of the structure is encrusted with life. It's an awsome dive, expecially if you're a macro photographer with good bouyancy skills.
I was told that the boat would be taken out of the water this winter and refurbished with private cabins.
Last summer accomodations were simple, but comfortable enough. There were bunks below in two separate, dormitory-like areas down below. No linens were provided.
Heads are spartan, but not disgusting. There are 4 showers on board so the wait for a shower is never too bad. The common spaces are bright and comfy. The galley served big, heaping piles of comfort food.
There is plenty of space on deck for tanks and gear for 20 passengers. They provide Nitrox via a membrane system which filters Nitrogen out of the gas. The resulting mix is different after each fill. (ranging from 29% - 34% if I remember correctly.) If you have an 02 analyzer you will want to bring it along.
It's not a cushy boat like an Aggressor, but I have no reservations recommending the Ultimate Getaway to someone who wants to eat, sleep and dive.