Just wanted to pass this along. IF you use barrels for floatation, you're gonna need a bung wrench (also called barrel stopper wrench, barrel stopper tool, and a number of other more confusing terms.). It's cheap (the plastic ones, which are all you need, run around $10) and looks like this:
It will let you get in between the barrels, even when in the water, to loosen or tighten the bungs, adjust floatation, see if they're unaccountably full of water, etc. etc.
I mention this because we DIDN'T have one until today, and were using all manner of inappropriate and half-witted things to make do.