Bilge outlet placement

[GaryAK]

Is there a "sweet spot" or "rule of thumb" to follow when placing mushroom bilge outlets on the hull sides. They used to go through the transom which has been replaced. Basically, I'm asking how far forward of the transom and how high above the water line I should install them. Going on a 20 ft. flat bottomed boat.

 

[steelespike]

Re: Bilge outlet placement

I don't think the placement fore or aft is much of a problem. As far as the height as high as possible without making it difficult for your self. My only caution is not so low as to allow water to enter the boat with a heavy load.Years ago I bought an old Garwood boat that had an auto bailer
would draw the water out a syphon at speed.It had a knee to keep it above the water line.
The po loaded a big gas generator aboard to be taken in the morning for repair.They found it sunk in the morning.

 

[GaryAK]

Re: Bilge outlet placement

I don't think the placement fore or aft is much of a problem. As far as the height as high as possible without making it difficult for your self. My only caution is not so low as to allow water to enter the boat with a heavy load.Years ago I bought an old Garwood boat that had an auto bailer
would draw the water out a syphon at speed.It had a knee to keep it above the water line.
The po loaded a big gas generator aboard to be taken in the morning for repair.They found it sunk in the morning.

Thanks, Steelspike. It is a Harvey dory with lots of reserve buoyancy due to hullside flair so it will take a lot of weight to make it squat. My biggest concern, as I understand it, is that the higher you pump water, the less efficient the pump becomes. That said, I've got at least 20 inches of clear space above waterline to work with before I get into built in storage, gunnels etc. My 1st boat and you'd have to pack for an expedition to find someone with less knowledge/experience than I have. Thanks for the help!

 

[Boatist]

Re: Bilge outlet placement

It makes a very small different how much water it pumps if it only about 3 foot of lift. I like my outlet on the starboard side about 4 inches down from the top.
The reason I like it there is when at the helm I can turn it on and look over the side and see if it is pumping out any water.

Water flow is affected some by lift and more by the type of hose you use. The hose that smooth on the inside has very little resistance by the hose.

 

[GaryAK]

Re: Bilge outlet placement

It makes a very small different how much water it pumps if it only about 3 foot of lift. I like my outlet on the starboard side about 4 inches down from the top.
The reason I like it there is when at the helm I can turn it on and look over the side and see if it is pumping out any water.

Water flow is affected some by lift and more by the type of hose you use. The hose that smooth on the inside has very little resistance by the hose.

Thanks for your input on lift...that was really bugging me...and outlet placement. I have corrugated hose but plan to switch to smooth bore. I saw some @ West Marine..I think Shields mfgrs. it. It seemed very rigid. Maybe I can soften it up enough in hot water to make the few bends I'll need. Doing a lot of part making/dry fitting now. Will be about 3 months before Alaska softens up enough to do the glassing. Getting antsy!