SV Pilgrim - 1979 Morgan 382 - Homeport: Beaufort, NC

Wednesday, September 24, 2014

Installing Electric Bilge Pumps - Bilge Modifications Part 2

If you missed the initial post in this series here is a link back…“Bilge Modifications – Part 1

After allowing the lower bilge, formerly the holding tank, over a month to air out and dry, we returned to paint both the upper and lower bilge.  The paint prep began with a TSP (tri-sodium-phosphate) scrub down and rinse.  This was followed by some very awkward one arm, blind sanding.  Once the surface was prepped we applied four coats of Interlux 2000E barrier coat to both upper and lower bilges.  The upper bilge then received a couple coats of white paint. 
Looking down into the freshly painted bilge.
Next step… install bilge pumps.   

Save for needing one 12V Ultra Safety System Pumpswitch Jr.  (anyone out there have one to spare?) we were able to construct Pilgrim’s new bilge pump system from  equipment on hand.  The system is comprised of one manual and three electric  pumps.  The manual, Henderson Mark V, will be installed in the cockpit.  The three electric pumps will be installed in the bilge at differing elevations.
Elevation diagram of Pilgrim's three electric bilge pumps. 
 The daily use pump, smallest capacity and lowest float switch, is a 300G/H Jabsco Diaphragm pump. This pump is mounted under the galley sink.  The float switch & pick up line are mounted in the lower bilge on bracket fabricated from starboard.
Bracket for mounting lower pump pick-up and float switch.
The foot of the bracket rests on the floor of the lower bilge and the top flange of the bracket attaches to the floor of the upper bilge via a couple screws.  This assembly is mounted aft in the bilge with the scrum box resting at the forward end of the lower bilge.
Filter for diaphragm pump on left.  Discharge hose for middle pump and wiring for lower float switch on right.
An inline screen filter for the diaphragm pump is mounted on the cross brace just below the cabin sole

The next bilge pump in elevation is a 2000G/H Rule pump.  The Ultra Safety System’s Pumpswitch mounts directly to the bilge pump.  The float switch for this pump is also tied to a high water alarm.  The pump & switch are mounted approximately 4” above the floor of the lower bilge on a bracket made of starboard.
mounting bracket for middle bilge pump & float switch.
Like the first bracket the foot rests on the floor of the lower bilge and the top flange screws into the floor of the upper bilge.
Middle bilge pump installed in lower bilge.  Base/screen for upper pump is mounted in upper bilge on right.
The top flange on this bracket serves as a base for the upper, 3700G/H Rule bulge pump.
Upper bilge pump installed.  The middle and upper pumps have not yet been fully wired or plumbed in this image.
This assembly is mounted at the forward end of the bilge with the discharge hoses running aft.
Looking down into lower bilge with all the pumps, switches, wiring, and plumbing installed on the lower two pumps.

At present, I’ve temporarily wired the lowest pump to the starter battery and run the discharge out the galley sink drain sea cock.  This set up will deal with the small accumulations of water that find their way into the bilge.  Once we get further along with installing the new electrical system, then I will finalize the wiring.  Plumbing the discharge hoses will likely wait until after the engine install.

For additional images and notes check out the Bilge Modifications Photo Album


  1. Jeff -
    Be certain that your wiring to the bilge pumps is adequate to carry the full load current of *all three* pumps running...

    Also, I found that normal bilge pump switches are not capable of carrying the current that the 3700 GPH pumps demand without a significant voltage drop (and consequent drop in performance) - see this post:


    1. Bob,

      Thanks for the warning about standard bilge pump float switches. The specs I found on the 3700GPH pump state it draws 15.5 amps. The Ultimate Safety Systems switches I am so fond of are rated for 15 amps - bummer. I did find a Aqualalarm Heavy Duty Pump Switch that is rated for a max of 20A ($39.99 @ Defender).

      Fortunately on Pilgrim, I am able to make the wire runs for the bilge pumps relatively short - approx12 feet round trip, none the less I will size the wiring conservatively.

      Good to hear from you.