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backcreeksailor 04-17-2009 07:18 AM

Manual Bilge Pump
Ok, so I'm rewiring my first system and getting rid of the mess of spaghetti and wiring splicers left by the PO on the current electric bilge pump. No problems there.

But I have a question about the manual bilge pump. After sitting in the yard since last fall with no batteries in it, the bilge was full almost to the sole. I tried then unsuccessfully to pump out using the manual pump. So I'm not sure if the pump itself needs replacing, but I'm confused about the pickup hose.

First, it's at least twice the diameter of the Rule 1500 discharge hose, which seems like it would take a LOT of water to make it even pump in the first place. But while I was working on the electric bilge pump, I notice the hose for the manual snakes past the electric and disapears under the mast through a round pipe that's about 6" in diameter and appears to lead to the area under the shower pan. When I try pulling it out gently, it seems to be attached to something on the other side, but I have no idea what is holding it.

So my questions are:

1. Is the diameter of the hose SUPPOSED to be this large?

2. If the answer to #1 is yes, then is this system only intended for emergency use when the boat filled above the sole?

3. Does the pickup hose location I described sound normal?

4. If the answer to #3 is yes, then are there any ideas as to what the other end of the hose is connected to that won't allow it to be pulled free?

sailingdog 04-17-2009 07:47 AM

Yes, the hoses on most manual bilge pumps are rather large, since they are usually diaphragm pumps, and can move a fair bit of water but are low speed high volume... rather than an impeller based pump that is high speed low volume, so need a bigger hose.

The pickup location sounds a bit odd...but the reason it could be stuck is it may have a strum box on the end of the hose, and that may be too big to pull back through..
Photo courtesy of

A strum box is basically designed to help keep debris that could clog or damage the pump out of the hose. :)

backcreeksailor 04-17-2009 08:20 AM

Is it normal for the strum box pickup location to be forward of the mast like I described?

On most boats, (yours for example), where is the strum box location relative to the mast?

And is it very likely a strum box that's too big to be pulled out of that access pipe would have been set in there before the sole was glassed? Because I see no other way to get to that area short of cutting a hole in the shower pan fiberglass... I'll mess with it again today and try twisting the hose to see if whatever is on the other end rocks round (e.g. maybe just snagged and not really permanently stuck back there).

sailingdog 04-17-2009 08:26 AM

Well, it would help if you said what particular boat you owned...since this may or may not be a standard setup on it...

Again, in general, when asking questions, you should provide as much relevant information as possible... make and model of the boat, the bilge pump, etc would be helpful. I'd highly recommend you read this POST to help you get the most out of sailnet.

backcreeksailor 04-17-2009 08:35 AM

Sorry... thought I had annoyed people with so many questions that they already knew... :p It's a 1979 C&C 30 MK I.

sailingdog 04-17-2009 08:39 AM


I'd recommend you put that either in your signature or your user title... since that makes it readily available... :)

As for the pump... most diaphragm pumps are fairly easy to rebuild... if a rebuild kit is available..and that is usually far less expensive than replacing it. Could the pump be connected to the shower sump??

backcreeksailor 04-17-2009 10:55 AM

I haven't concluded that the pump itself isn't working yet since I don't know if the pickup is currently above the bilge waterline with the way the boat is leveled on the jack stands. But it's good to know that I can do a rebuild kit rather than replacement if it is the pump.

In the head area under the teak slat floor risers there's an approximately 2'x2' a 1" deep shower pan canted downward toward the stern, which just has a circular area of drilled holes in the fiberglass at the lowest point for the gray water to drain directly into the bilge. It looks like the pipe I mentioned forward of the mast goes directly to that area and is canted downward toward the stern too.

I don't know for sure that there's not a deeper well (sump) under that pan. But based on the lowest point of the bilge that I can see and the relative location of the shower pan, I doubt it.

Where is the manual bilge pump pickup placed in "your" boat?

sailingdog 04-17-2009 11:24 AM


Originally Posted by backcreeksailor (Post 476561)
Where is the manual bilge pump pickup placed in "your" boat?

My boat really doesn't have a bilge to speak of.. it's a trimaran, and if you lift up the cabin sole inspection port, there's only about 1.5" of "bilge". I sponge it out once in a while and have a portable rig setup if necessary. I also am adding manual bilge pumps to the two amas... which need to get pumped out once in a while. :)

chef2sail 04-17-2009 01:26 PM

On our C&C we have a integral molded sump pan with a 1/2 inch hose conected to a strainer running under the teak shower grate floor. This hose connects to a Jabsco quad pump located under the handsink compartment. The outlet for the pump runs to a thru hull well above the waterline so when we shower we can pump the grey water out of the boat directly. We use another of the quad inlets as an empergency bilge pump out so it has a 20 ft 1/2 inch hose connected and coiled under the sink should the occasion arise.

Our manual bilge pump is 1 inch hose runs the length of the boat and out a thru hull above the waterline. The strum box ( Thanks for identifying the correct name saildog for it as I used to call it a spachetti strainer) is located in the lowest part of the bilge aft of the mast. Since we are a centerboard our bilge is faily shallow (12 inches and a flat run). It takes a fair amount of water to prime the diaphram pump. Make sure there are no holes in the 1 inch hose or you will be like Sisyphus rolling the rock up the hill only to have it roll down and start over.

sailingdog 04-17-2009 03:06 PM

Glad to help Chef... :) Why would you call it a spaghetti strainer... hmm...maybe because you have kitchen stuff on the brain... ;)

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