Electrical, Bilge Pump Switches, Part I: Analysis and Installation

One of two bilge pump switches on Oystercatcher
Every boat that has a bilge has a bilge pump, or at least it should. How else do you remove the unwanted water that accumulates in that space at the bottom of the boat? Some bilge pumps are manual, some are driven by engines or generators, and still others are electrical. It's the latter, i.e., the electrical bilge pumps, that you most commonly find on cruising sailboats. This is not to say, however, that many people don't have manual bilge pumps or engine-driven pumps as back-ups. Nevertheless, electrical bilge pumps, powered by direct current (DC) through the battery bank, are the standard. These electrical pumps must have electrical switches, and these electrical switches must not only be easily accessible but also reasonably close to the cockpit, if not in the cockpit itself. In this two-part article, I describe my rationale for the location I selected, and I describe how I installed and wired these bilge pump switches. These tasks were part of the greater task of a complete rewiring of Oystercatcher, my Ericson 25.
Blue Sea Systems PN 8263
When I purchased my boat in 2009, it had but one electric bilge pump, and it was undersized at that. The switch for this diminutive bilge pump was located adjacent to the access door to the lazarette - the small door you see behind the companionway.
One of the two previous owners had also installed a DC distribution panel in this area. Neither the bilge pump switch nor the DC panel was in a good location. The battery box sat just behind the door. This was the factory-designated location for the battery by Ericson. For good reason the folks at Ericson did not install the factory-original DC panel in this location. DC panels are not ignition protected. The same can be said for bilge pump switches. This means that a spark from the panel switches or the bilge pump switch could ignite the gas that is emitted from a flooded lead battery while it is charging. Since I would be using flooded lead batteries (as opposed to gel-cells), this panel and this bilge pump switch had to go.
When the time came for me to rewire and replumb the boat, I thought long and hard about the bilge and the bilge pumps. Ultimately, I decided to rebuild the Whale brand manual pump (that was original to the boat), and I decided to install two separate electric bilge pumps. For more on these subjects, see my articles under the heading of "Plumbing."
Whale brand manual bilge pump in the process of being rebuilt
At the bottom of the bilge would be the day-to-day electric bilge pump, a Whale brand Supersub Smart 650. Above this would be the emergency electric bilge pump, a Rule brand 2000 GPH (Gallon Per Hour) pump. An engine-driven pump was, for me, not an option, since my Ericson 25 has an outboard motor, not an inboard diesel. I liked the Supersub 650, because it allowed enough room for the bronze strum box for the manual pump.
Given that I would have two electric bilge pumps, I needed two bilge pump switches. I opted for the Blue Sea Systems brand switch, because I had heard too many bad things about cheaper switches. Plenty of people said that, if they had to do it over again, they would buy Blue Sea Systems switches from the start. These particular switches, just like most switches, have three settings - On, Off, and Auto. For the day-to-day bilge pump, I planned to set the switch to Auto. This would allow the float switch within the Supersub 650 to pump out water whenever it sensed that it was high enough. For the emergency bilge pump, I planned to keep the switch set to Off. This pump was only for emergencies, and hopefully, I would never need to use it. In the event that I did, I planned to push the switch to the On setting. I should note that Blue Sea Systems has made the On switch idiot-proof. It is spring-loaded, so that it cannot remain in the On position without a human hand pressing it. The idea, of course, is that this prevents someone or something from accidentally turning the switch on (when unnecessary) and killing the battery bank (and thus eliminating the power source for the day-to-day bilge pump). This spring-loaded switch, however, can be over-ridden simply by placing a shim of some sort (piece of cardboard, wood, etc.) behind the switch. This, then, in an emergency allows you to focus on other more pressing issues - like bailing water or using the manual bilge pump.
In terms of the installation of the bilge pump switches, I considered putting them in the cockpit, where they would be easily accessible while underway. These types of Blue Sea Systems switches, after all, are designed to be in the elements. Ultimately, I opted against putting them in the cockpit on account of the space that was required for the wires behind the switch. The only reasonable place in the cockpit where I could install the switches was on the inboard side of one of the cockpit lockers. If I had installed the switches in this location, then the wiring behind the switches would have impeded my use of the locker. For this reason, I opted to put the switches in the galley area of the boat, not far from the companionway.
I had already decided to install the AC distribution panel on the bulkhead near the stove and the mahogany spice rack. The large piece of cardboard in the picture below represents the AC panel. I experimented with one location and then another, and in the end I decided to mount both bilge pump switches directly above the AC panel. There was just enough space for both of them, and this location, close the hull, ensured that the wiring behind the switches would not hinder usage of the cockpit locker.
As I have said many times, my guiding principle in the refitting of this boat was that every modification and improvement be both functional and aesthetically pleasing. Not wanting the switches and other parts of the exposed portions of the electrical system to appear ill-fitted with regard to the overall design of the interior of the boat, I took the time to make trim pieces for these switches out of solid mahogany. The interior, after all, had been well-trimmed with mahogany by Ericson long ago. Why not make that which looks good look even better?
If you care to know more about how I obtained this mahogany, see my posting, "Electrical, AC Distribution Panel." If you care to know more about sapele mahogany, which is what I used for this project and many others, see my article, "Companionway Hatch Construction." If mahogany is out of your reach, and you wish to trim out your switches and panels in a similar fashion, there are many alternatives.
Here's one of the trim pieces as it initially appeared with sharp-edges, soon after I made the cuts.
Right angles rarely look good on anything on a boat. Therefore, I decided to round the corners of the trim pieces to give them a curvy and inviting appearance. For the sake of consistency, I used a dime to scribe the arcs for each corner. I've used all sorts of common items like this to scribe arcs for different projects on this boat.
Afterwards, I dry-fit these trim pieces and the others that I planned to install in this area, just to make sure that everything would fit as I hoped it would.
In the picture below you see pencil marks (beside the large rectangular hole) indicating where I initially planned to put one of the bilge pump switches. I thought that I would put one here and the other one just above it. This was before I had ever constructed the mahogany spice rack. Fortunately, I delayed my cutting of the holes for the bilge pump switches. The spice rack does an excellent job of making use of formerly wasted space. For more on this project, see my article, "Spice Racks, Custom Mahogany."
I installed the AC distribution panel first. I then used this as a reference for installing the two switches, so that they would appear both plumb and level.
I installed the trim pieces first. I then used these to mark the rectangular holes that I needed to cut.
A drill bit, 1/2 inch in diameter, removed almost all the material within the rectangular marks.
The Dremel, with a fiberglass cutting bit attached, helped me to break through all of the holes.
The keyhole saw finished the job.
The finished installation didn't look too bad. The AC panel and the switches were balanced, well-trimmed, and looked like they were supposed to be there. Now I just needed to make sure that all the other components that I planned to fit into this space looked just as good. I also, of course, needed to do the wiring, so that all of these components were not just aesthetically pleasing, but also fully functional.
This ends this posting on the steps I took to install the bilge pump switches on Oystercatcher, my Ericson 25.

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