: i've had similar thoughts (but don't specifically know particulars of the
: guzzler diaphram) - form over the diaphram as it is depressed. add any pcs
: nec to attach - get nice close tolerances. like it for a tandem idea.

: hehe,
: like if one was to have a bulkhead, use 2 pces of thin ply separated by some
: foam for the b/h, mount a diaphram betw, form over the back, pre route the
: foam separator to use as the intake 'line' as well as the 'outake' so no
: pipes and put thousands of little holes thru the deck so as you were
: pumping you'd have like your own little water display.

: joke -if you had airtight hatches & valves maybe could use the front
: hatch as the chamber, and no body needed at all. the whole b/h is the
: diaphram.

Mike,

Right on, building the pump body would produce a nice installation. The body is just a cylindrical volume with inlet and outlet ports, and a flange to capture the diaphragm. For foot pumps, I think diaphragms make more sense than pistons because of the restricted stroke. Pistons are good for long stroke, low diameter geometries. For short stoke large diameters, pistons and diaphragms have essentially equal function, but diaphragms seem to be the more simple, elegant solution. And, good quality diaphragms are cheap and easy to come by. If increased flow rate (above the Guzzler) is desired, simply buy a rebuild kit for a higher volume pump, or make the diaphragm of neoprene left over from that spray deck project… And if you want to get fancy, do the body in carbon.

Sam