Shower Sump/Gray Water Tank

[P69]

I was not satisfied with the sumps available on the market because they are flimsy and did not have enough inputs or reliable screens to prevent debris from interfering with the float switch and pump.

My goal was to create a sump/gray water tank to capture debris-laden and soap-contaminated effluent, from multiple sources, to prevent those fluids  from entering the beep bilge, causing a difficult-to-clean, stinky mess. 

I designed it to fit in the bilge  a little bit after of the mast, where that 'step' is, the forward end of the main bilge.  I made a card board mock-up to get the dimensions, then made a foam mold. This shape maximized the volume by conforming to the bilge and hull shape at that section of the hull.  It is almost water tight and has an input chamber that is separated from the main chamber where the float switch is by a bronze screen.  It has bronze hose barbs threaded into tapped holes of the input chamber so it does not rely on sealants.  The interior is gel coated and the lids to the main chamber and input chamber are held down with 1/4" bolts, with a neoprene gasket.

The float switch is held in place with a custom bracket that is epoxied to the interior of the main chamber.  The bracket clamp is removable and the four bolts are threaded into holes tapped into the epoxy/glass substrate the makes up the fixed part of the float switch bracket.  The output is a 1" bronze hose barb tapped into an epoxy block to ensure watertight exit point.

Input connections are:  head pan drain (3/4" bronze hose barb), head sink drain (3/4" bronze hose barb), shower pan drain (1" bronze hose barb), AC condensate (3/4" hose barb), and fwd chain locker drain (1 1/2" fiberglass hose barb).  The fwd chain locker input barb is 1 1/2" OD fiberglass tube which is fixed to the input chamber with epoxy putty.  I added a bead around the exterior end of the fiberglass tube and ground it to mimic a the barb on a bronze hose barb: tapered so a hose can slip over the top and, when clamped, can't pull off without riding up over the glassed-on barb.

The pump is a diaphragm pump (whale gulper) that is mounted outside of the bilge to keep it out of that wet environment.

This sump is fastened to the hull at two points, one aft/stbd side and one fwd/port side.  These two brackets are made up of an epoxy/cloth blocked that is glassed to the sump and each has a hole tapped for a 5/16" bolt.  The hull has a fiberglass (poly/cloth) flange glassed to the hull.  With the sump in place and bolted, it cannot be tossed around in rough seas or move during a knock-down.  The only air flow is through the input tubes.

Here is a link to more pictures.
http://bodylens.com/Gallery/thumbnails.php?album=48

[S/V AMITY]

  Great design!  In a sump application is a diaphragm pump less prone to fouling than an impeller type?  Do you still have the pull-knob pump switch in the head (next to the shower) to override the float?

  For my system, will be adding an indicator light to indicate when the pump is energized.

[P69]

Amity,

Centrifugal pumps need to be submerged to pump and I wanted  few electrical connections/devices inside the sump.  I'm not sure if the location of the pump will be lower than or at the same elevation as the lowest part of the tank.  It's very likely that the pump will be higher.

The diaphragm pump suck air with no detrimental effects. I expect the pump be in the gallery somewhere, down low and air to be in the line between the tank exit barb and pump, so that pump will have to suck that air out until water gets to it, then continue until the float switch turns it off. 

I had a toggle switch  at the shower to control the sump pump. i'll probably put it back, but maybe not. I will have an override switch that will run the pump regardless of where the float switch is, just not sure if it will be in the shower or somewhere else.  Because there are multiple inputs (AC condensate, head sink drain, shower drain, chain locker), the sump will have more than just shower water, although that will, most of the time, be the source of most of the volume.

[S/V AMITY]

    Will the fridge drain be plumbed into it?  A project we have on the list is to run the fridge drain through a trap and a vented loop to the sump.  Right now it drains into the deep bilge which isn't good.

[P69]

No, the fridge drain will not exist. I removed the fridge and will build another one without  a drain. Well, it will have a drain, but the drain will be used for periodic cleaning or unplanned spills.  During normal use, the drain will be sealed. During cleaning, I'll hook a hose to it and run it to a bucket or bilge, depending on the filth level.    The new fridge design will have a fridge bottom that I can reach without stretching  and a compartment underneath to easily access the drain barb/valve  when I need to clean it.  There will be a shelf a few inches above the bottom to keep stuff out of any fluids that find their way down there.

[S/V AMITY]

    We have the Pearson standard-issue box.  Bottom is too far down to even reach.  At some point will rebuild with modern insulation and a better shelving system.  Be interested to hear how you'll be configuring your new fridge. 

[P69]

Amity,

This link has diagrams and pictures of the new fridge/freezer design.  The cardboard mock up represents the box liner. All insulation will be outside of the cardboard mock up (4" or 5" of polyiso/cryogel combination to get R30).  I plan on making the liner out of prefab fiberglass panels or lay them up myself, cut to shape, then assemble. The other possibility is to make a male mold, but that might be a lot of work, but with a male mold the sanding is all on the outside.

Note that in the diagrams and most of the pictures of the mock up, the port side of the boat is to the right and center of the boat is off the left side of the diagrams/pictures.  Also, the fridge will be aft, where the sink used to be. I am swapping sink and fridge locations.
On

http://bodylens.com/Gallery/thumbnails.php?album=55