: I'm no expert, in fact this is my first greenland kayak, but I
: didn't have the patience to build float bags and didn't want to
: spend the money to buy them. Instead I took some white foam
: panels (used as insulation at home depot), cut them to fit
: between the stringers, stacked them on top of one another (they
: are only about an inch thick), then duct taped some white
: polytarp I had over them (christmas gift style) for
: waterproofing. If I ever get completely flooded, I'm pretty sure
: some water will get into the foam and take forever to dry out.
: But for general usage the panels are all above the chine
: stringer and therefore well above the bilge so they should stay
: dry.

Have to remember you need volume to make this work. Fresh water weights about 60 lbs. a cubic foot and sea water about 63 lbs. Subtract the weight of the materials used for floatation and you'll get the weight the floation will float. If it won't float the boat and you, there's no point in adding it in the first place, the frame will float itself just fine.

For an average boat and average paddler, say 40 lb. boat and a 180 lb. paddler you'll need something over 3 1/2 cubic feet of floatation. Takes more than a 4x8 sheet of that 1" foam to do it, more like 1 1/2 sheets and that's using all of the foam with no waste.

Bill H.