Bilge Pump Plumbing on Catalina

[JimMcGee]

The Preamble
I've had this musty, slightly diesel/oily smell coming from the bilge on my boat since I bought it. It would seem worse some days than others and a bilge sock got rid of the worst of it. It wasn't an oh my God smell, more of a I know it's there so it bothers me smell. The source was the mechanic who changed my fuel filters when I bought the boat last July and managed to spill quite a bit of fuel into the bilge and didn't do a great job cleaning up.

With the boat closed up for weeks at a time during the winter I really started to notice the smell.

So last week I sucked out the bilge with a shop vac, soaked it down and scrubbed it with Simple Green as a degreaser, rinsed it, sucked it dry again. Hit it with Spray Nine, scrubbed, rinsed and dried it again.

This weekend I'll clean/degrease the engine so I can spot if there are any leaks.

The Question
My Catalina 30 has two bilges. One under the cabin sole, and an upper bilge under the engine/transmission/fuel tank. Water entering the boat from the shaft seal drips into this upper bilge. Once this bilge fills to a certain level a bilge pump pumps into the lower bilge where a second bilge pump pumps the water out of the boat. This seems like an odd system to me. In fact on my buddies '05 Catalina 30 there is a pipe cast into the stringer that allows this upper bilge to drain directly into the lower bilge.

Is there any logical reason why I wouldn't want to just put a t-fitting into the line so the upper bilge pump could also pump directly overboard?

I realize there would be some back flow into the lower bilge but there shouldn't be much if the t-fitting is above the upper bilge pump.

Drilling through the structure of the boat in this area and adding a drain pipe is not an option.

[sailingdog]

You probably want something to absorb or separate the oil out from the engine bilge, so you're not pumping it overboard. If you don't do something to capture the oil, you may find yourself facing some nasty fines.

[JimMcGee]

Dog, I've been thinking about this and it's really two different issues. One is how do I control bilge odors. That means keeping the bilge as dry as possible and as clean as possible. So once the engine and upper bilge are cleaned up I'm going to install dripless packing on the shaft seal. When I haul out in the fall I'll change over to a PSS seal. That will keep the upper bilge pretty much dry, and an oil absorbant cloth under the motor will catch any drips.

I guess the other question is does this setup of pumping the upper bilge to the lower bilge make sense? And the more I think about it if I address the water from the shaft seal it's more or less a moot point.

Jim

[sailingdog]

A dry bilge makes for a happier boat and owner.

Originally Posted by JimMcGee

Dog, I've been thinking about this and it's really two different issues. One is how do I control bilge odors. That means keeping the bilge as dry as possible and as clean as possible. So once the engine and upper bilge are cleaned up I'm going to install dripless packing on the shaft seal. When I haul out in the fall I'll change over to a PSS seal. That will keep the upper bilge pretty much dry, and an oil absorbant cloth under the motor will catch any drips.

Yes, that's true... and if you've got other constant leaks into the bilge, you've got a problem you need to fix.

I guess the other question is does this setup of pumping the upper bilge to the lower bilge make sense? And the more I think about it if I address the water from the shaft seal it's more or less a moot point.

Jim

[DwayneSpeer]

I can see why you can't pump the upper bilge overboard once you have taken care of the potential oil problem and yes you can tee into the discharge line just put back flow valves ahead of both pumps. That is essentially what I have. I have a large high flow pump that I can turn on manually and a small pump that is automatically actuated and they both discharge thru the same thru-hull. It keeps my bilge dry and still allows me to take care of larger problems if they should arise.

[JimMcGee]

Dwayne,
I've heard two schools of thought on back flow valves in bilge pump lines. One is that they keep you blige dryer by preventing back flow.

The other is that they're a potential point of failure in a safety system as the valves can be stuck in the closed position or can trap water in the lines between the valve and through hull that can freeze and rupture the line.

The more I think about this the more I'm inclined to leave it as is after changing over the shaft seal. As far as I can tell there is no other water entering the bilge other than the shower, and I usually shower in the marina. I can deal with some water from the shower when we're on the hook by sucking any residue out when we get back to our slip. It's rare that we're going to be out for more than a couple of days at a time.

Thanks guys,
Jim