manual diaphragm bildgepump discharge though hull above or below waterline?

[phorvati]

Mine is discharging below waterline. Is there a reason for this?
I am hauling out for some maintenance. I am going fill and glass over old 1-1/2" through hole for head discharge (i switched to composting toilet and no longer need it). I am also addressing 4 bronze Apollo valves threaded onto though-hull by adding adapter plates so things are not cross threaded.

One of Apollo valves threaded into 1-1/2" through-hull services a hose for manual diaphragm emergency bilge pump.
Can't that discharge above waterline? I would gladly plug two 1-1/2" though-hulls.

[Bowdrie]

Originally Posted by phorvati

Can't that discharge above waterline?

Absolutely!
Underwater discharge increases pumping effort and slows down the flow.
It also adds another potential leak/flood point.
By all means go to an above waterline discharge.

[Wotname]

IMHO - always above (well above) the waterline or into a self draining cockpit.

[phorvati]

Nice. So I don't suppose someone can point me to write up on plugging 1-1/2" holes with polyester. I will try to get to 12:1 bevel as best as I can, I have heavy glass tape from when I was rebuilding my bulkhead in 2017. I wonder if resin is still good.

[Sailor Sailor]

You must use epoxy resin, not polyester. There is a good explanation of how to do this in "This Old Boat" by Don Casey. After beveling, clean with acetone. Basically, you attach a nonstick surface, for instance waxed plasticine, to the inside so it conforms to the curve of the hull, then apply multiple layers of woven cloth and resin over the hole on the other side, covering the bevels and extending out beyond the circumference of the hole.

For each layer wet the surface with epoxy on a paintbrush, apply the cloth, remove bubbles, and repeat until you have about 5 layers. Wipe up drips of epoxy resin. It should generate heat as it cures. When cured but still tacky, repeat with more layers until new layers cover beyond bevelled surface on the outside. Then remove the nonstick surface on the inside and apply more layers to the other side until bevelled surface is covered. Use a sanding grinder to smooth and paint.

[phorvati]

Originally Posted by Sailor Sailor

You must use epoxy resin, not polyester. There is a good explanation of how to do this in "This Old Boat" by Don Casey. After beveling, clean with acetone. Basically, you attach a nonstick surface, for instance waxed plasticine, to the inside so it conforms to the curve of the hull, then apply multiple layers of woven cloth and resin over the hole on the other side, covering the bevels and extending out beyond the circumference of the hole.

For each layer wet the surface with epoxy on a paintbrush, apply the cloth, remove bubbles, and repeat until you have about 5 layers. Wipe up drips of epoxy resin. It should generate heat as it cures. When cured but still tacky, repeat with more layers until new layers cover beyond bevelled surface on the outside. Then remove the nonstick surface on the inside and apply more layers to the other side until bevelled surface is covered. Use a sanding grinder to smooth and paint.

Boat is laid up in polyester. I have epoxy barrier coat that i will put on the outside to any exposed areas. If boat was done using epoxy, I would use epoxy, since its polyester, other than strength, I don't see a reason for epoxy. Its stronger, but also more expensive, harder, more time consuming to work with.

[kapnd]

Polyester is fine, why mix apples with oranges?
You might consider saving a thru hull, just in case you develop a need for more water at a later date. It could be plugged for now.

[Manateeman]

Buy a nipple and carefully examine the threads on the valves. A new valve is not going to ruin your new adaptor plate. Screwing in a nipple into your old valves by hand will give you a feel for the threads. Pipe taps are expensive but maybe you can borrow one. Don’t over cut the female threads. A tap will chase out tiny defects but if the old valves have bad threads it’s better just to dump them.
We would only use epoxy and triaxial glass.
The manatee crew