SailNet Community banner
1 - 4 of 4 Posts

·
1979 C&C 30 Mk I - 2QM15
Joined
·
172 Posts
Discussion Starter · #1 ·
This may be a dumb question, but here goes:

Bilge pump hoses generally have long lengths of drain hose routed to their own through hull fitting on the side of the hull above the waterline. Which often results in a significant quantity of water that rolls back down the hose and into the bilge after the pump shuts off. And gate valves to prevent this backwash are highly discouraged due to potential blockage issues.

So why don't boat builders utilize one of the existing through hulls that are under the water line already (like from the head or galley sink) to expel the bilge water? At least in my boat, for the cost of a simple pvc Y-fitting. This would result in a bilge pump drain hose that would be less than half the length that it is now. It would only have to pump/push the water half the vertical height that it does now. It would eliminate things like bilge drain staining on the side of the hull. And I'm "assuming" (maybe incorrectly), that since the sinks don't have siphoning effect issues, this would be eliminated too. So why not?
 

·
ancient mariner
Joined
·
439 Posts
if you tee in to a connection like the sink you would have to have an anti siphon 90 degree elbow in the bilge pump line installed as high several feet above the waterline to prevent sinking the boat.
 

·
ancient mariner
Joined
·
439 Posts
backcreeksailer----i should have said a 180 degree elbow like the ones used in the head plumbing mounted high enough so there would be no chance of siphoning back into the bilge.
 

·
Old Fart
Joined
·
514 Posts
if you tee in to a connection like the sink you would have to have an anti siphon 90 degree elbow in the bilge pump line installed as high several feet above the waterline to prevent sinking the boat.
If you use a diaphragm pump you don't need the anti-siphon elbow. You will want to locate the pump above the water line. That is the setup I have and have had no problems. Of course I ALWAYS turn off the valve on the thru-hull before I leave the boat for any length of time.
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top