Added 2nd Electric Bilge Pump

[Jon W]

I've read several comments about water run back into the bilge without the in line check valves in the hose so thought I'd pass on what I have found. Note - regardless of in-line check valves, when I intentionally filled the bilge to test the pump system, the 1500 always left ~ 1 1/4" of water in the center bilge section that had to be sponged out. The pump discharges out of the transom up high on the starboard side near the back stay chain plate. See 1st photo.

I've just finished adding a Rule 3700 GPH electric bilge pump for redundancy of my original Rule 1500 GPH. The primary pump is the 1500. The 3700 sits high in the bilge and expect it will never be used in anger. I ran continuous runs of 1 1/8" and 1 1/2" Trident # 147 Marine Bilge and Baitwell hose, each with a Marelon vented loop. I removed all of the in-line check valves.

I installed a 1 1/8" vented loop between the bulkhead and galley sink just under the counter top. (See 2nd photo). When I did a test run of the new pump system, the run back without the in-line check valves was only the water in the hose from the pump to the vented loop. About 1/4" of water which is well below the switch activation point. The pump did not cycle after waiting ~ 30 minutes.

[Noah]

I am a bit unclear as to your final system design.
1. A separate discharge through-hull for each pump? Where does the new pump discharge?
2. Two vented loops?
3. Why two sizes of hose?
4. Does the new pump have its own float switch?
5. Why vented loop(s) at all? Seems like you will now just leave a bunch of water in the hose uphill of the loop? Usually vented loops are to prevent siphon-back when discharge is below waterline, or near waterline. Your discharge pictured is nearly at deck level.

[Jon W]

Hi Noah,
      1) Yes separate discharge thru hulls for each pump. The 3700 has a 1.5" hose from pump to vented loop then tying to the discharge
          side of the manual pump to the existing 1.5" thru hull in the lower part of the transom. Both the manual and 3700 pumps use the
          same thru hull. See 1st photo.

      2) Yes two vented loops. One for the 1.12" hose from the 1500, and one for the 1.5" hose from the 3700.

      3) The 1500 requires a 1.12" hose. The 3700 requires a 1.5" hose. Taking losses into account, the max output for both pumps
          running at the same time (hopefully never) should be in the neighborhood of 60 gpm.

      4) Yes. Each pump has its own float switch and breaker. The 2nd photo gives you an idea of the different levels of the pumps and
          float switches. The 3700 pump and switch mounting brackets are made of starboard fastened to 1x1" aluminum angles glassed
          into the bilge.The mounting brackets are easily removeable to move the pump or float switch out of the way to get to the keel
          bolts if needed. See 3rd photo.

      5) If you have in-line check valves in your bilge hose, you have water in them all the time upstream of each check valve. I didn't
          want the potential failure mode of a check valve failed closed.The vented loop provides the anti siphon function for the 3700
          which discharges at the bottom of the transom. The vented loop for the 1500 is up that high to match the exit in the transom to
          keep water upstream of the loop, and to be above the drawer I have below the sink. I believe this is why there is only ~ 1 quart
          of water run back into the bilge when the pump shuts off. The vented loop also allows making a needed tight U-turn in a small
          space.

I couldn't find anything on adding a 2nd electric bilge pump so will be adding a write-up to the Tech WIKI. As always, you're welcome to come by and take a look if thinking of doing something similar.

[Noah]

Now I've got it!! Very nice set-up! Yes, I would like to come by and take a look. Also, I don't have any good photos of my boat under sail (other than selfie-style). Care to have a "race" (LOL!) / joint photo session sometime where we can snap some shots of our "babies" underway?

[Jon W]

Let me know when you want to come by. I recently got an early retiement severance pkg from work so anytime works for me. I'm up for the photos, but want to wait until I get the UV strip replaced on my original genoa. Right now, with all the torn strips flapping in the wind it looks a little like the ghost ship in Pirates of the Carribean.

[Noah]

Man, jealous! Congratulations! Dang, you beat me to retirement! Since you've now got so much time on your hands, I'll email over my unfinished project list...the key is under the mat