Adding multiple bilge pumps

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September 2001 -- I won't win any awards for quality photography here....

Attaching the pumps requires some creativity.
I have a fundamental fear of drilling holes in the boat. It's always amazing to me that people will take a drill and stick a hole in the laminate in the bilge. Sure, it's the thickest part of the hull. But who needs a hole that puts water in direct contact with the interior of your laminate for years on end?

I built a model of my design out of cardboard to test the concept, then cut pieces of 3/8" fiberglass laminate to match. You can buy sheets of structural fiberglass laminate at McMaster-Carr
(I love that place!)

The pieces were expoxied into place, and the joints reinforced with a fillet of thick epoxy putty.

Wear a respirator and gloves
when cutting and sanding fiberglass!

After sanding it smooth, I painted it to seal the edges. Maybe that's overkill.

The only reason it's high gloss black is because I had an old can of InterLux single part topsides paint sitting around. That's definitely overkill, but it didn't cost me anything, and it's definitely tough waterproof paint!

When I bought the boat, there was the standard whale bilge pump in the cockpit, and an electric impeller pump mounted by the engine. The electric was manual on/off only.

I'm adding dual auto pumps in the the bilge, and will keep the existing impeller pump as a backup to my backup.
Stella Blue doesn't have deep bilges, and I expect to store a backup anchor and additional chain rode in the bilge
as well. This means there won't be a lot of room to hold water before it hits the cabin sole,
and a problem will get big a bit faster than in a big heavy cruiser. So, the more pumps the merrier!

Here's what it looks like when assembled. Sorry about the photo quality but I spend all my money on boat stuff, not cameras.
(click on the pic to make it bigger.)
The hardest part will be laminating the Pepsi cans into the hull.

At the bottom is a little 500gph pump that will handle most stuff.
It is attached to a stepped-down 1/2 inch smooth walled hose, that pumps out under the toe rail. That setup will reduce the pump's output in a huge way, but the small diameter hose will allow me to avoid needing a check valve, and it's a small amperage draw so I don't care if the pump runs three times as long to remove water.
It's a cheap pump ($17) and I have a spare.

To avoid accidentally epoxying the shelf permanently into place I smeared melted wax all over it.
It would have been a lot easier to
put wax paper in between the parts,
but I didn't have any wax paper on the boat
and I had to keep moving forward.

I also put wax all over the bolts that will eventually hold the shelf in place. I want this assembly to be removeable for maintenance and repair. It will be much easier to unbolt it and take it out to work on it.

If there's a problem, the little pump won't be able to keep up, so I installed a 2000gph pump on the shelf. It's four inches up, and should be clean, high and dry all the time. If water gets to be four inches high in the bilge, the big boy kicks in. I'm thinking about installing an alarm in the circuit, but right now I'm just thinking...

That pump drains out the stern, also high on the topsides.

To mount the shelf in the bilge, I'm going to attach little fiberglass blocks to either side of the bilge. After washing the area with acetone to remove all traces of oil and other annoyances, I ground down lightly to get through the paint and to rough up the laminate underneath. The wand attachment for the Handy Dremel Tool proved it's value when I dropped it. That sure would have been a bummer I'd dropped a running 120V electric motor in the bilge....

Using West System with Colloidal Silica, I made a strong putty and stuck the little blocks in place.

The next day, my Handy Dremel tool did a good job of grinding down around the edges to rough things up a bit. I'm going to create the thickest goopiest epoxy putty imaginable, and put strong fillets around the bottom, sides and top of the blocks. Note that the holes were already drilled.

If I had to do it again, I'd drill the holes ahead of time, and use the shelf to brace the blocks against the bilge while the epoxy set.
The problem with the way I did it is that it's not perfectly level. To fix this, I'm going to use the epoxy putty to create a small shim.

Here it is all settled into place. The waxed bolts are positioning the shelf correctly.

I'm terrified that I didn't get wax all over EVERYTHING, and that one small piece is being permanently bonded to the wrong other small piece...

(Again: I could have just slipped a piece of WAX PAPER in between the parts.)

Well, it's the next weekend and all's okay. Time to do the wiring. I found some 10 guage three conductor wire on sale at West Clearance for 44 cents a foot, so what the heck, I'll used big wire and guarantee that there will be no voltage loss to the pumps.

Each pump is connected with butt connectors, then covered with heat shrink tubing. I filled a syringe with marine grade silicone and packed it well before shrinking the cover with a heat gun.

Then, just because I'm really paranoid, I covered everything with super-sized heat-shrink tubing. Again, I packed it with marine grade silicone, then applied the heat gun. As it shrank, the extra silicone squeezed out the ends.

My last boat went Hot due to an old bilge pump connection, and it cost me thousands of dollars to fix the damage. I want to make sure that doesn't happen to me again!

There we go! All that's left to do is wire it back to the batteries and connect the switches.
The little pump exits the boat under the rail on the port stern quarter, the big pump exits by the stern -- up high. No core in these areas of the hull, so installing the though hulls was easy. I used a marine plywood backing plate and sealed it all with LifeCaulk.

December 2001 --
Here it is all hooked up, with the bilges freshly painted!

November 2002 -- Here's the old original bilge pump. It's ugly, but works fine, and it's a pretty expensive pump. Rather than waste it, I'm going to rebuild it and install it as a
third, manual on/off pump.
One of these days...
It moves about 6000 GPH.

April 2002 -- Reflections after six months. If I had to do this again, I'd change a few things. First off, I'd make the platform lower, and have the big bilge pump about 2 inches up, not 4. This is because the switch adds an inch or two to the depth before the pump kicks on. Thinking about it, I realize that the little pump kicks on when there's an inch or so of water, and so if the big pump was 2 inches up, it would kick in when the little pump couldn't handle things.
No big deal, though, and I won't re-do it.

The other thing I discovered is that the concept of using the 1/2 inch hose to avoid needing a check valve didn't work for me. Maybe on a smaller boat it would work, but on a 38 foot boat, my hose run goes about 15 feet or more. There's enough water there, in a 1/2 inch hose, to dump enough water in the bilge to keep it wet all the time. I don't want that.

My C&C Landfall 38 has these large fiberglass 'beams' just laid transversely across the boat. They created a few areas in the bilges that are 1/2 inch deep between the 'beams'. When I cleaned everything to repaint, I filled in those low spots with epoxy paste to make them level with the top of the "beams', except for the one where the bilge pumps sit. When the pump stops, I only want enough water to flow back to fill that one little sump area in the bilge,
but I want everything else to be as dry as possible.

So, bottom line, I stuck a check valve in the small pump's line anyway.