A few experienced and respected Tri sailors weighed in, Ira Heller doesn't like the idea as it reduces safe loaded weight for cruising. Jim Thompson sits on the fence and thinks maybe in the rear of the main hull is OK, but not in the floats. Paul Butler (Teamvmg F-32 builder) says "must have the facility to dump it all very quickly" I guess like reefing early, he suggests fresh water ballast may lead to regrets if dumping is delayed. Good point! Martyn is of the same opinion and adds wisdom, "I'd keep it as butt simple and light as possible and if you have an option of adding ballast, be sure to have a sure, quick way to dump it"."
On the other hand Skiff and Tri sailor Ron Radko says "Depends on how much ballast and how much crew you have. I know on our 28 the upwind speed difference in planing conditions is huge if you have crew on the rail vs in the cockpit. (7.5 to 8 knots vs 10-12). If you were shorthanded having 3-400 lbs of water ballast in the float would be the same load as the crew on the rail without having to be out of the cockpit".
Ian chimed in with
"Using drinking water would be a good option when cruising, as one is just
shifting ballast that is already on the boat, rather than adding weight. It
would be viable, but the piping could get rather complex. Probably not worth the
effort for most. Easier to carry extra water in plastic Jerry cans and then move
to windward float on long legs".
Structurally there are no problems Ian said, "the floats can take the extra weight". Is it worth it? He says
"While adding ballast can also slow the boat, ... usually the gain in
performance is higher than the loss from taking on the weight, so the extra
ballast weight is justified".
Edit: See Capt Pauley's recomendations.