rebel xt in a drybag stored in kayak hatch

would like to take my slr with me on kayak trip (just day trips).
would probably keep it in there for a few hours.

safest way to store it would be in a waterproof drybag in rear hatch of kayak. concerned about condensation.

i bought a pelican box but it doesn't fit in the hatch. they do sell desicants but i thought i would check here first.

anyone have experience with this sort of thing.