Fred,

It's not possible to do that in my production Beneteau, no room below
the grade of my shower bottom to put such a tank.

In desperation, not having any other ideas to work from or any
recommended designs that don't involve a sump, I am thinking of
replacing the Jabsco shower pump with a Gulper 220, and eliminating the
pump guard.

My hope is that
(1) The Gulper 200 will be more succesful at getting the liquid out
before the suction prime is broken, and less water will flow back into
the shower.
(2) Eliminating the pump guard and shortening the hose 10%, will reduce
the volume of fluid that can reside in the system, and flow back to the
shower. I believe the pump guard can be eliminated because the Gulper
220 materials specifically mention that it isn't needed.

Does anybody see any foley in doing this ?

Dan


wrote:
I built a 39 foot FG sailboat about 20 years ago. The shower drain
plumbing (almost) never gave me a problem. Let me describe it.
Perhaps you can fit your boat similarly.

The shower (and two sinks) drained by gravity into a 6 gallon sump tank
located in the bilge below all drains. The sump was emptied by a small
pump. The pump discharge hose was lead up to form an anit-siphon loop
well above the (heeled) water line then over board via a sea cock that
was located in the center of the stern above the waterline. Being on
the center the exit was (almost) always above the water even when
heeled. The anti-siphon break in the loop is needed to prevent
possible back siphoning into the sump tank. Of course, when the pump
emptied the tank it cavitated and the pump was shut down by a manual
switch. Water would then drain from the loop and return harmlessly to
the sump tank. Voila!

Hair is always a problem with pumps. My wife and I were careful after
showering to wipe hair from the strainer and dump in the garbage (in
port) or into the head (at sea). Periodically (like every three months
while living aboard), the pump would have to be removed from the sump
tank and de-haired --- yuck!

BTW this scheme allowed me to have only three thru-hulls below the
waterline: engine input, head input, and head output.