Very bad bilge pump arrangement - SailNet Community
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post #1 of 2 Old 02-12-2010 Thread Starter
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Very bad bilge pump arrangement

I live aboard. My neighbor has an old classic wooden powerboat and I was keeping an eye on the boat as he is working in another city and his wife is working in a different city and is away 5 days a week. At about 1 pm I went out for a while and everything looked fine. I was back an hour later found the swim grid underwater and the boat heeling to port about 10 degrees or so. I wasn't aware of his bilge pumping system except that it wasn't keeping up. We quickly put a 12 volt pump on board with its own fully charged battery. Another neighbor brought an AC pump over and we plugged that in. It took over an hour to make much difference with the 2 pumps. We were gaining but quite slowly. We couldn't see where the water was coming in. After the swim grid was out of the water we investigated further. His charger wasn't working even though plugged in. His 2 battery bank was at 3 volts. We put a portable charger on his battery bank. Once his batteries were up a bit we found the float switch was not working all the time only sometimes. But the worst problem was where his bilge pump was plumbed to. The galley sink is on the port side. It is a fairly low boat with the cabin sole below the waterline. The bilge pump was connected to a T in the sink drain which has a through hull just under the waterline. The output from the bilge pump runs under the floorboards and slightly uphill to the T. Once the port side was down the 6" or 8" the water was coming in through the outlet. It can't siphon because the sink drain acts as a siphon break but the whole output line was under as well as the T connection. We estimate over 1000 gallons was in the boat. I think when he gets back this will be changed. As will the inoperative battery charger. And the float switch.
I do not think a bilge pump should ever go to a below the waterline outlet. It should be led up under the side deck and down to an outlet above the waterline both so this never happens and so a constant output is visible all the time.

Living aboard in Victoria Harbour

Last edited by mitiempo; 02-12-2010 at 07:42 PM. Reason: add
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post #2 of 2 Old 02-12-2010
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So to avoid this all he really has to do is install a more reliable charging system and run his bilge pump hose up well above the water line and then back down to the pump and T.

I've heard of people doing the T into the sink drain and am installing a third pump myself. I decided against that arrangement because I like to close all below water line valves when I'm away from the boat. Instead I'm going to punch yet another hole in my stern. A bilge drain is best kept simple but I can understand why some might think the risk was worth it.

Your post also reminds me that I have a shower drain that is only a few inches above my water line. Yes it has an anti-syphon mounted well up but I think I will also install a valve on that thruhull. Thanks.

Have faith that the oceans are going to rise and flood the world, that plague and pestilence brought on by Climate Change is going to punish us for not believing. Please do as they say it is our only hope. :P
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