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b393capt · Guest

Where could I find some good insight into designing the plumbing to get
water out of my shower drain to an underwater thru-hull, and staying
out of the shower? The plumbing in my Beneteau allows some water to
come back into the shower drain at the base of my head, enough that
when I heal the boat, it coats the bottom of the head floor.

Seems after the pump stops, the extra water in the hoses to the pump
slowly let out water, maybe only 4-6 ounces, but enough to fill the
bottom and come up a small amount above the drain.

I suspect its designed poorly and I could upgrade it myself. I noticed
for example the diaphram pump wasn't design to be connected to
underwater thru-hulls.

The current plumbing has a hose running up then down the wall to a thru
hull, in a loop,with an in-line filter and a diaphram pump at the top
of the loop. After I pump the water out of the head, even if I close
the thru hull, water runs back into the shower drain within a minute or
two. If I stick a cork in the bottom of the drain, the water gets
around it and forms a tiny pudle in the middle of the head anyhow.

Dan

Peggie Hall · Guest

b393capt wrote:

b393capt · Guest

Peggie,

This one will be a little tough. Yes, I did try pumping longer in fact
for a very long time, it didn't even improve a little bit.

Yes, your right, I did mean a strainer rather than a filter. Says
Jabsco on the outside and is maybe 3 inches wide and round.

I am leary about adding a one-way. Will adding a one-way valave just
after the sump really be a solution, or just delay the water coming
back into the sump by another 30 minutes or so? I was thinking it
won't work because the seal isn't very good on these things, and any
hair in the line will just make it worse.

Dan

p.s. Your book was great !

Peggie Hall wrote:

b393capt · Guest

Is there some best practices guide in boat building for designing the
plumbing for a shower drain ?

Guest · Posted: Tue Dec 12, 2006 9:16 pm Post subject: Re: Shower drain plumbing design

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 *** 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.

b393capt · Guest

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

fred.gerbstadt@verizon.net wrote: