A while back I submitted a question about bilge pump installation in the deep bilge aft of the engine. Useful suggestions about mounting it on a stick to lift it out. I replaced a failed pump with a johnson spx 1000 only to discover that it will only lift about 4 feet which is not enough. The current limiting factor is that the hose and thru-hull are 3/4” inside diameter. Of course whatever I get needs to fit the narrow width of the bilge. I’d like to avoid having to drill the hull for a 1 inch thru-hull.
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Zygote was equipped by Sam L. Morse Co. with a Rule 02 (1500 US gallons per hour) pump that outlets to 1.125 inch (one and one-eighth inch or 28.6 mm) ID hose.
Does the job and leaves less than 2 mm of water in the deep bilge.
Z also has a Henderson Mark V manual diaphragm pump that takes water from the deep bilge through 1.5 inch (38 mm) ID hose. A Henderson Mark V is rated to lift water 1.5 metres (4.9 of the foot of King Someone or other of England). It does the job also.
I can only suggest fatter hose and/or more power in the pump. I am ignorant if tapering fatter hose to your slim through-transom fitting would be critical.
I don’t have the specs of the IDs of Z’s through-transom fittings to hand, but I expect the ODs of the fittings match the ID of the respective hoses. No need to stand in the way of getting bilge water out, right?
What I did on Flyer has worked perfectly for 25 years. I had a stainless steel bracket made out of square tube (the same height as the depth of the bilge). It fastened to the back of the fiberglass engine pan below the bilge hatch. It has a flat plate that sits on the bilge floor. That plate was tapped to accept mounting screws for the rule pump and float switch. You mount the pump and switch to the plate and lower it into the bilge. I split the hose at the top of the bilge to aid in removal during maintenance. Instead of having a different through hull for all the different hoses, I purchased an extra bronze exhaust fitting, mounting it on the opposite side of the rudder. I then simply built a manifold on the inside of the transom. All of my pump outlets feed into this manifold and use the one through hull.
Thanks, Flyer. I’ve already installed the new bilge pump on a post with a hose connection for detaching it when necessary as well as coiled long electric wires so that it can be removed without clipping them. But I am interested in installing a back-up pump as well and have thought about how to do this without drilling for an additional fitting on the transom, without any solutions (I would not T into the hose for a variety of reasons). I wonder what you mean when you refer to a “manifold” on the transom and how you avoid the issue of pumping back into the bilge well. Can you describe this in more detail or supply a photo? Thanks.
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Paul et al.,
I recently ran across this older test in Practical Sailor that might prove helpful for you:
High Capacity Electric Bilge Pump Test - Practical Sailor (practical-sailor.com)
Best,
Mike
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Thank you, Mike. That article is much appreciated. I had ended up using the Johnson XPX 1000 which did work when I shortened the hose by about 1 foot for a more direct lift to the top of the transom where the thru-hull had been installed. I’m still considering installing a back up pump a bit higher in the bilge and would use the Shurflo or Attwood recommended in the article. But I remain reluctant, however, to drill for another transom thru-hull.
It seems that your situation is with the Johnson SPX 1000 pump’s lift capacity and the existing 3/4" hose and thru-hull setup. One possible way out is to get a more potent bilge pump which has higher lift requirements but is still able to fit inside the narrow width of your bilge. Choose pumps for deeper bilges or bigger head applications that will allow them to work along with your current hose size. Furthermore, you may want to consider a 3/4" to 1" adapter, but you should be careful of the fact that this may cause restrictions that will negatively affect the flow. Assuming you are insistent on the existing thru-hull, be concerned with pumps that are designed specifically for 3/4" fittings and have been proven to be very effective in deeper bilge areas. Always verify that any new pump can be securely mounted and that it works efficiently within your space constraints.