Lew Hodgett wrote:

"TB" writes:

I have a new Henderson Mk V pump, will it be suitable for plumbing into
the system to empty the holding tank offshore, or will i need a specific
type. Any recommendations?


Henderson Mk V



I can use a bicycle pump or similar to evacuate my holding tank
offshore. I close both air vents, open the sea valve, and pump up
the holding tank with air. I watch the joker valve for back leakage
/ wear indications, and now, use a 12 volt tire pump. When the
pressure reaches about a pound, out goes the poo.

If I did not open the sea cock, I could blow the contents out the
deck pumpout fitting. I have an elbo I am tempted to screw into the
deck fitting if ever any PWC gets too pesky, port side. Two elbows
and a ball valve could provide a fully aimable poo cannon. Long
range shots might be dangerous for the cabin crew / head attendant /
leakage monitor. That capability suggests a thru hull for sewage may
not be required. I have pressure tested the system when new with
water. I can nervously saw I would trust it to about 10 yards with
short wait times at the ready. Pirates? Bring 'em on!

This system also obviates no need for a working shoreside pump, and
requires only a holding tank on the gas dock, which could remove
many objections by marina operators about pumpout maintenance costs.
It could also make boats cheaper. Of course, a flexible vacuum hose
to a parking spot for a city services sewer sucker truck up on the
bank would still be needed. Oh, and a level indicating clear
overflow tube / vent outside the dock holding tank, wired to a
pumpout service call buzzer / alarm. I would not normally employ my
system to blow sewage up more than about 3 feet, realistically.

Such a system would contribute greatly toward lowering shoreside
pumpout equipment costs, as a suction rated pumpout hose on the dock
is no longer needed. Mind, a leaky sewer hose on deck is quite
noticable and might be repaired more quickly than a plain
cantankerous vacuum leaking one.

Sell the pump.

Terry K