I redesigned the piston on the homemade footpump. Er, actually I checked out the mechanism on my MSR water filter and borrowed a few ideas.

Where do I start... here is the blueprint www.chipsandresky.com/paddles/images/footpump3.jpg These pistons are driven off a foot operated teeter. The piston will tend to rock side to side as the teeter moves around but the seal is good enough that you don't get a loss of compression. This design is vastly simpler than the previous version. A preliminary "bucket" test indicates that they will work okay. Here's another shot of them www.chipsandresky.com/paddles/images/piston2.jpg The residue is mold release wax. The push rods are morticed/glassed into the heads.

Here's a shot of the stuff boxes (notice the fancy pump terminology ) and check valves www.chipsandresky.com/paddles/images/twin_pumps.jpg These will protrude through a forward bulkhead and are designed to be fully serviceable from a front access hatch. Here's the teeter still under construction www.chipsandresky.com/paddles/images/teeter.jpg That is the part that failed in my previous design. This one is much more serious. I'm optimistic overall; I'm hoping they will move an honest one pint per second - what's that 7.5 GPM? Should be ready for a test in the coming weeks.

www.ChipSandresky.com