Cold water/weather and wind are real concerns. Getting in and out of the water can be sketchy. Cramps in legs and feet suck. Leaking waders are no bueno.
In my 30 or so years float tubing, those are my list of dangers that I make plans to deal with.
These are my concerns as well, particularly getting in and out of the float tube.
I've had a couple incidents while getting in or out of the tube.
On my maiden voyage in my Outcast Prowler float tube a couple years ago
nature called me to shallow calf deep water near shore. While getting back in the tube I sat my butt down and the combination of wet vinyl seat and wet waders caused the float tube to launch out from under me like a well played tiddly wink.
I found myself on my ass in 2' of water while my float tube drifted towards water too deep for me to recover it.
Only a quick rebound back to my feet allowed me to recapture the runaway tube. Uncomfortable lesson but a good lesson none the less.
Takeaways,
1) install seat belt on float tube.
Trip to hardware store to buy 2" nylon strap material and buckle set to match.
It's been discussed before on the old site that this could be a danger were the tube to flip. Using the risk vs. reward
thing, for my money I'm much more likely to slide out of the tube in deep water without seatbelt than I am to flip the tube in deep water and not be able to escape by unbuckling my self.
2) when getting in the tube always have both hands gripping the sides of the tube
pockets or straps while sitting down.
The vinyl seats on the Outcast Prowler are very slippery when wet and sat on with wet waders.
I'm not sure about other models or brands.
3) I attached flipper saftey straps as well to retain a flipper should one come off while fishing.