> I think my pump is too long for that space,

I meant that when you use the pump it is stuck through the tunnel of the skirt the pump can go straight down to the bottom of the kayak. I keep the pump tethered under the deck. Although the whole idea of pumping out a boat with two hands is squirrely anyway. When I made my seat I left just enough of a flange (1/2") at the front extending down to strengthen it with minicell supporting it under sit bones and under thighs to outer edge leaving a space underneath for a squashed dry bag, sponge, or those small lunch box sized dryboxes.