On 12/4/08, as part of a "Florida Keys Wish List," I posed the following question:

50. Who has taken their own vessel to the Dry Tortugas, Garden Key and Fort Jefferson. Please describe your cruising experience. Would you recommend this passage to other cruisers? If so, what would be your minimum vessel size recommendations.

Responses follow:

Claiborne,
Enjoyed reading your wish list. I wish we had cruised the Keys more recently than the winter of 2004-5, so we could help answer some of your questions. The hurricanes of 2005 obviously changed a lot of things that we aren't aware of right now.
However, I doubt if the passage from Key West to Dry Tortugas has changed much, and we did that in our 35 foot trawler back in January  2005. We had a good weather window, and stayed anchored off the fort for 3 nights before returning to Key West (stopping at Marquesa Key both ways). The trip out was a piece of cake – relatively calm winds and seas. The return was a bit of a ride for the first 30 miles and we had to "tack" across 5-6 foot waves with a period of about 12 seconds, and reduce speed to around 5 knots or so until we got within the reefs which helped dampen the seas a bit. This was better than waiting another day when the forecast was for really rough weather!
We'd do it again in a heart beat. It is an idyllic place and unique from every perspective. The staff at Fort Jefferson is superbly friendly and helpful. Water wasn't much of a problem, although we did consciously conserve (washed dishes once a day, were careful when brushing teeth and washing, took showers on the day-cats, etc). When we returned after six days out, we had used less than 40 gallons of water.
I think one could make the trip in a smaller trawler (certainly a smaller sailboat) with a good weather window. You could always stay anchored at Fort Jefferson until a front passed (usually 3-4 days) if
you got caught. All the local fishermen come into the anchorage at night, and stay there during bad weather in relatively small boats.
The depth in the anchorage was about 20 feet, if I recall, so scope is important. Once set, our SuperMax held well, but there is some grass on the bottom that caused a problem for a couple of other boats that were there at the same time.
Bob McLeran and Judy Young