Bilge Replumb Advice?

[One Chance]

I'm currently refitting my 36' C&C. Thinking of redirecting my bilge discharge line & teeing it into either gally sink dischage or head sink discharge. Currently my bilge discharge runs to the stern(approx 15' uphill run) when BP cycles off the contents(15' x 1") drains back to my bilge-constant wet bilge. My reasoning for teeing BP discharge to head or gally discharge is that it would shorten the bilge discharge run to approx 4'(4' x 1") & therefore would have much less water returning to the bilge when BP cycles off. I also could eliminate one thru hull fitting.
Does anyone have any thoughts on this change?

Thanks!
One Chance

[sailjumanji]

Are both of the discharge thru-hulls you are planning to use large enough for the bilge. I guess one risk would be that in high pump rate situation, it would be easier to flow up the T into the sink, than thru a restricted thru hull. That could make a real mess.

I would also be concerned about this in really high heal situation. In a real tragedy, taking on water in the bilge and then it pumping thru to sink T and coming back into bilge via sink.

How about instead, just adding an above-water thru hull nearer to the bilge pump?

[Calif.Ted]

I don't think that's advisable, all pressure from the pump would be lost at the TEE, open to atmosphere at drain, essentially reducing output to "gravity flow" at that point.
Also, ABYC specifies bilge discharge should be above waterline at all angles of heel, that's why most are high towards the stern.

[NahanniV]

How about adding a second smaller pump with a 1/2" hose mounted lower in the bilge than the existing pump.

The 1/2" hose would be easier to route to a closer/better discharge location and have less volume to backflow.

The existing pump becomes the emergency pump.

Cheers,
JM.

[MBWhite]

IMHO you can't have too many bilge pumps!

If I understand you correctly, your issue is the bilge is always wet from the residual that does not pump out and drains back, and that is what you are trying to eliminate here?

I'd leave that pump alone and install a smaller pump in he bilge next to it, plumbed however you'd like. Since it is not your main pump you could even put a check valve in it (keeping in mind they too can jam in the open position so you still need some anti backflow design/protection) to keep even more water out of the bilge. When you get a lot of water your capacity has increased, and when it drops below where your main pump shuts off it can pump it down even further, win-win. I'd have them on separate float switches too.

Anyway, if I understand you correctly that is what I would do to keep a dry bilge in your situation.

[barnakiel]

I think all installations I have see always ended up well above the waterline. Ours does too.

b.

[geoleo]

Originally Posted by One Chance

I'm currently refitting my 36' C&C. Thinking of redirecting my bilge discharge line & teeing it into either gally sink dischage or head sink discharge. Currently my bilge discharge runs to the stern(approx 15' uphill run) when BP cycles off the contents(15' x 1") drains back to my bilge-constant wet bilge. My reasoning for teeing BP discharge to head or gally discharge is that it would shorten the bilge discharge run to approx 4'(4' x 1") & therefore would have much less water returning to the bilge when BP cycles off. I also could eliminate one thru hull fitting.
Does anyone have any thoughts on this change?

Thanks!
One Chance

run it out the side

[MBWhite]

Originally Posted by NahanniV

How about adding a second smaller pump with a 1/2" hose mounted lower in the bilge than the existing pump.

The 1/2" hose would be easier to route to a closer/better discharge location and have less volume to backflow.

The existing pump becomes the emergency pump.

Cheers,
JM.

....And I agree what this guy is saying too! (posted at the same time LOL)

[roverhi]

Electric bilge pump on my boat is tee'd into a Stand Pipe that is also the drain for the galley sink. Works fine but still have the problem with back flow when the pump shuts off and a wet bilge sump. Another issue was back syphoning until an anti-syphon loop high up in the galley cabinetry was added.