OD28 Thru Hull Question

[Tom Potter]

I have a question concerning thru hulls under the Head sink. I have two side by side in that location. One is much larger than the other. The smaller one is hooked to the head sink. The larger one (1-1/2) is now hooked to a bilge pump with a check valve. I plan to change that and install a vented loop.

My question is, are 2 thru hulls in that area standard? And if so, what is the larger hooked to. I'm sure OD would not have hooked it to a bilge pump. It must have been used for something else. Maybe one of the PO's put it in, I'm just not sure, maybe something to do with the shower. Any ideas?

Tom

 

[31seahorse]

Hello Tom, The thought of a bilge pump connected to a 1 1/2 inch thru hull under water is a problem waiting to happen. I would think that the bilge pump has to overcome a good bit of water pressure when it starts. A shut off valve at the hull would make me more comfortable than a nonreturn valve for times when the boat is unattended and the bilge pump is off. Bilge pump discharge lines I am familiar with are above the waterline by quite a distance. Perhaps the thru hull was originally a discharge for the head or holding tank. There was that arrangement in an Irwin 31 Citation we once owned. On our ODay 30 the head discharge is aft of the head area by about 2 to 3 feet. The basin in the head area discharges about 1 foot above the waterline on the port side (head to port too).

 

[Marc Bergmueller]

On my 1980 Oday 28 the sink cabinet includes one thru hull for the sink and one for the bilge both hooked up as yours is. Both well above the waterline.

 

[Tom Potter]

Thanks guys.

Phil,
I should have been a little more descriptive as both thru hulls are indeed above the water line, and each has a shut off.

Marc,
It sounds like our boats are plumbed the same. It seems to me that the large thru hull is somewhat over kill for a automatic bilge pump.