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Securing the Bilge Pump Hose

posted Sep 4, 2011, 5:53 PM by Christopher Hubbell   [ updated Sep 7, 2011, 1:32 PM ]
Aft view - bilge pump hose
Installing the new electronic bilge pump has not been nearly as simple a job as I'd anticipated.  As if that hasn't been the case with nearly every project!  Nothing has been a showstopper in itself, but rather a series of decisions which required time to think through.  I'm finding that in most cases when I'm not sure what to do, the best thing is to wait on it.  When the time is right, the right choice seems to work itself out.  Such is the case with the question of what to do with my bilge pump hose.

The hose has a rather long run to make from the center of the boat to the cockpit locker, and finally out the aft through hull.  It's guided quite well until it hits the cockpit locker, at which point it has been flopping around in a manner that makes it hard for me to get into the lock for maintenance, and hard to store thing in the locker.  The reason it took so long was that I wanted to come up with a good way to secure the hose along its path.

The first thing I considered was using the cable hangers I've been using throughout the rewiring project, and holding it in place with a zip-tie.  I'm pretty sure it would work for 99% of the sailing I do.  Unfortunately, I have trouble seeing that hose staying secured if it were full of water and in rough seas.  Even a long term vibration from running the engine I think would fatigue the plastic.  If nothing else, the thin surface area of the zip tie seemed like an abrasion point that could come to no good end.  I knew this solution needed to be scrapped.

The second thing I considered was a steel band with a rubber liner and a single mounting screw.  These are often used for securing cable bundles in electrical applications.  What I don't like about this solution is that the heavy hose is secured from a single attachment point which over time would do a lot of flexing.  I was also not sure I could find it in a suitable variety of stainless as to stand up to the damp marine environment.  I hate rusting stainless...

After spending some time perusing options at Lowes for securing plumbing, wiring, and conduits I arrived at what I think is perhaps the perfect solution for securing the specific type of 1-1/8" bilge pump hose I have employed.  A PVC conduit hanger for 1" conduit fits snugly over the hose and has two holes for screws.  This means the clamp is slightly flexible, and can be mounted with the nice 316 stainless #10 x 1/2" screws I keep on board.  No rust, and two-point attachment.  Very slick.

The second issue was how to attach them to the hull.  While a bit of a pain in the neck to fabricate, I believe I made a good choice.  I had a sheet of 1/2" plywood left over from another project which I took a hole saw to and created 5 round attachment points.  I'm partial to making round backing plates for things because most of my hull employs compound curves.  The circle is thus easier to get a uniform alignment with.

I used a small stiff wire brush mounted on my drill to scuff the areas where these discs needed to attach, then thoroughly cleaned them with acetone.  I then wetted out the wood and hull with neat Epoxy.  Next, I mixed a peanut-butter consistency blend of West Epoxy with Colloidal Silica adhesive filler, which is my favorite blend for securing attachment points to the hull.

The discs were then pressed into place and a fillet carefully applied to the seam.  This used up all of the thickened epoxy.  I then made a small batch of neat epoxy and with a small brush, coated the exposed plywood to give it some water resistance.  Not really critical being high on the side of the hull, but I like to to the right thing given the chance.

The next day I returned and secured the clamps and hose to the pads.  The installation is solid as a rock and looks very seaman-like if I do say so myself. 

I still have to test the ability of this pump to push water through this distance and head, but I am confident it will work at least to some degree.  I selected a Sahara 1100 pump for an application most people use a 500gph pump.  Being double the normal flow rate on a pump which was highly rated in Practical Sailor's test for coming close to its published ability gives me confidence.  Will it pump at 1100 gph?  Of course not!  But if it can pump water with some reasonable volume I'll call this project a success.

Next is the wiring.  I need to snake the path from the bilge to the engine as I'm having trouble getting the wire through just pushing.  Then I just need to connect the switch and install the cabin panel it mounts on.  I'm seeing light at the end of this tunnel...