Convert grey water holding to overboard discharge

J

jasrri

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13832
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My 2001 Larson 330 Cabrio was constructed with a grey water holding tank (Lake boat set-up), which I would like to convert to an overbaord discharge. What is involved and level of difficulty? Please advise. Long Island South shore boater!
 
Do this only if it is legal where you boat. I have done it two ways. Method one would be to a though hull under both sinks and replumb the sinks to the through hulls. With this method you also need to add a shower sump and a through hull for it to pump out of. The second method would be to replace the grey water tank with a shower sump and a through hull. The second method is easier but requires you to clean the sump frequently. Both methods are fairly easy.
 
32Carv, you've confused me. Don't both your methods require a shower sump? Why would one require more frequent cleaning than the other as they both drain the same grey water? I would plumb each sink directly to an above waterline thru hull. For the shower, I'd use a sump/pump and plumb that to it's own thru hull.
 
The reason I suggested a shower sump pump for the first method is that I prefer the automatic float switch in the sump pump to discharge the water from the shower drain verus flipping a switch to turn on a sump pump. The shower drain is usually below the water line so you can't plumb it staight to a through hull. Just lazy I guess, but your way would work fine as well. If you use a sump pump to drain the sinks you get yucky things like macaroni and cheese, pieces of hot dog and other kid stuff.
 
Drop a sump pump and float switch into the bottom of the grey water tank. Then plumb a discharge line from that pump to an above water through hull.
 
Will a sump pum perform macerator like duties? I'm just thinking about all the crap that goes down our sinks and showers and it better have some ability to mash things up and spit them out the side.
 
No it will not. It is nothing more than a small bilge pump in a plastic box. That's why you have to clean the filter out once in awhile. THey clog up with soap scum and hair from the shower. I think if the sinks empty into one, it would be a mess.
 
Ah! Good to know! So it's just your basic bilge pump. Seems like there is a market for something like this.....
 
I think 32Carv has it right on with the first method. If sinks derain into a sump they would create huge mess with food stuffs going down but why don't you have the same with the galleysinks going into a grey water tank? Never heard of this. My 23' Fiberform cuddy had a sink in the 'galley' and it went straight overboard.
 
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