Home Improvement – Added Shower Sump

This weekend’s project, or one of them, was to add a shower sump to keep the bilge dry.  In Columbia’s infinite wisdom they allowed the shower to drain directly into the bilge.  This would not be a problem, but as with most bilges, there is no way to pump the bilge completely dry.  Because of the design of most bilge pumps, there will always be around 1/2″ to 1″ of water standing in the bilge.  This can make for a musty smelling bilge, and boat, after a few days.  Considering that most of the cabinets and storage opens to the bilge at the bottom (to allow drainage), a musty bilge can make clothes, and everything else, smell musty.  Add to this the fact that the ice box also drains into the bilge, and things don’t get any better.

There are two fixes that we have come up with to alleviate the problem of an ever-wet bilge.  The first was to install a shower sump to collect and pump out the shower.  The second will be to install a Norcold icebox conversion kit so that we don’t have to use ice in the icebox.

Over this past weekend I decided to tackle the shower sump.  It seemed to be an easy enough task and I had rehearsed and

planned it for several weeks.  I had taken pictures of the shower drain by holding my camera underneath where the drain comes out, and snapping away.  There was no way that I could have managed to have a look directly at it because the opening was too small – just enough for my arm to fit into.  As it appeared it has a small 1″ OD piece protruding from the drain that I could fit a hose and clamp onto.  I measure it by pressing a piece of paper against the bottom and measuring the circular pattern on the paper.  The drain does not have what looks like a real hose fitting, but something I could work with.  After all, this is not a pressure fitting.  There would only be water trickling into the hose I attached.  If there were a catastrophic failure here, the only bad thing to happen would be that the shower would once again drain into the bilge and I would have to figure out a “plan B” to fix it.  Okay, I would need about three feet of 1″ ID hose. Could be the cheap stuff, as this is uncritical.

Next step would be that there would have to be a place to install the sump.  I had purchased a sump from West Marine for around $125.  It would need to be in the bilge area in the event that something broke, so that any water could simply drain into the bilge.  I would also need 12 volt power to be available, or I would need to run additional wire.  I opted to install it in the middle section of the bilge where I would have plenty of room to install a small platform for the sump to sit on.

I could use an “L” bracket and mount a piece of wood just above the bilge pump.  There would be enough room to slide the bilge pump out if I needed to get to it, or just unscrew the platform and service underneath it as needed.  Great!  Had that all figured out.  Now, onward to where it should pump out.

I was NOT going to haul the boat out and have a through hull installed just for a shower sump.  It would need to be plumed to an existing through hull.  The logical answer was to plumb the sump pump to the galley sink.  The drains from the double sinks came together and had a one-way valve at the bottom, so this would be perfect.  The sump pump could pump the water into the sink drain, and the one-way would prevent it from coming up into the sinks.  So I would need approximate 5′ of 3/4″ ID hose.  The pressure on this hose would be minimal, so the cheaper hose could be used.  Again any failure under the galley sink would simply drain into the bilge, so we were protected.

I cut the wood platform and installed the “L” bracket.  I then fitted the platform into the bilge and screwed it into place.  I screwed it into one of the bulkheads, which would allow it to sit on the sides of the bilge area, and then fitted the sump onto it.  I then screwed the sump down.

At this point I drilled a 2″ hole in the forward bulkhead so that I could run the shower drain hose through it.  I pushed the

drain hose onto the drain, clamped it down, and ran the hose through the hole in the bulkhead.  It wasn’t easy to get the hose clamped onto the drain because I was working blind.  It was easy enough to push the hose onto the drain, but as you can see from the first picture, there isn’t a lot of room for a clamp to grab, so it took a few tries.  Once on, I tightened the clamp and it was on there to stay.

On the other end of the hose, I had to cut about 10″ off to complete the connection into the sump.  The sump had three inlet connections which each had multiple graduations where you could clamp a hose.  All I needed to do is find the 1″ hose inlet, and cut the next size graduation off.  I clamped the hose onto the sump and was finished with that part of the installation.

I was now ready to run the outlet hose over to the galley sink.  I had 5′ of hose, so I was not worried about not having enough.  I had to take an access plate off the side of the icebox under the sink and run the hose through there and into the bilge to the sump.  That done, and clamped, I cut the sink drain hose and inserted a “T” which I had purchased with the sump.  I clamped all the fittings and was finished with all but the wiring.

I was able to tap into the bilge pump wires for power.  Luckily the wire was heavy enough to handle both pumps running at the

same time.  Once taped into the existing wires and insulated I was ready to test the new sump.  I turned on the shower and let the sump start to fill.  At first the sump pump started, but would not pump water.  Thinking that it may have to prime, I turned it off and on a few times.  Within a few seconds it was pumping the water out of the sump.  It only took about four seconds to empty the full sump, so no problems there.

All and all it was a fairly simple installation.  On a “1 to 5” scale it probably rates a “2”.  The only concern I have is that I need to double-clamp the fittings that go from the galley sink to the sump.  They are connected to the through hull, and it is always prudent to double-clamp fittings connected to a through hull.  All that is left after that is to bring a shop vac down to the marina and dry the bilge completely.  No more musty boat smell from the bilge!