Leonard Jansen, who is one of the swimmers who is participating in next week's solo swim of 27 miles, gave me these tidbits in an email where I requested tips for my upcoming trial swim of the course next week. Thought I should pass them on as I know of a few local swimmers who are not seasoned veterans who, like myself, benefit very much from the wisdom of others... thanks Leonard!
I'm not sure what you are using for sunscreen, but one of the things that open water swimmers often do is to put on a layer of sunscreen, let it dry and then overcoat that with a heavy layer of Desitin 40% zinc oxide baby rash cream (or a generic equivalent). It's good to have some vinyl or nitrile disposable gloves to put that crap on because if you get it on your hands and then touch your goggles, it makes it hard to see. Better yet, have some one else put it on you with the gloves. Don't use latex - they rip/dissolve very quickly. If you are wearing a wet-suit, then you only have to worry about face/hands/feet. BTW, sunscreen that is good for running is not necessarily good for swimming because water-resistance is not the same thing as sweat-proof and you can't trust the manufacturers to tell a straight story. The best three that I know of are:
1) SolRx 44 or 50 SPF (not cheap, but a good bang for the buck)
2) Waterman's Scientific (EXPENSIVE!!)
3) Bullfrog Superblock SPF 50
The first 2 are almost impossible to get in a store (at least in PA). The Bullfrog is readily available. Regardless of what you use, the smear-on kind is better than a spray-on kind, as a rule. These (and Desitin) can be hard to remove - use original Dawn dish-washing liquid. Also be sure to use Vaseline under your arms if you are NOT wearing a wet-suit - I forgot it in my race 3 weeks ago and had hamburger for armpits after.
One thing about the race (and also applies to your swim, too): Since you generally plan for the worst - i.e. having enough feed, etc to last for 12 hours (12 oz * 24 feedings = 288 oz or 2+ gallons) - the fluid feedings can take up a good amount of space or simply be too big for a kayak. Two possible solutions: 1) resupply points along the course during the race or 2) Kayaker has something attached to the kayak that contains these. To the latter point, I have a synthetic MESH laundry bag that attaches to the kayak via short FLOATING rope and carbineers. I then use 2 liter seltzer bottles with 4 feedings in each and put them in the bag. The seltzer bottles are pretty tough, don't come unscrewed by accident too easily (and you can add duct tape over the cap, too) and they will float since they are only about 3/4 full. The kayaker then only needs to keep one in the kayak and the rest stay in the water until needed. (I get the mesh laundry bag for $1.00 at Dollar Tree chain stores.) That means having 6 * 2 liter bottles with 4 feedings each and the mesh bag has no problem with that. It does drag a bit on the kayak, but isn't exhausting.