Hunter 35.5 shower drain pump

[wilburleft]

Hello forum,

Newish boat owner. Thinking of installing a shower sump pump on my 1995 Hunter 35.5. Shower drains into the bilge where it sits until the bilge pump is triggered. But the bilge pump doesn’t get all the water out, leaves an inch or two. It gets pretty gross in the bilge. I’m attaching a pic showing the shower drain hose.
Could I install a sump pump right there by the drain hose and discharge it into the galley sink drain hose? The discharge hose would run uphill from the bilge into the cabinet that contains the galley sink drain hose, I think.
Thanks very much for any feedback.
Bill in Miami

 

[wilburleft]

I just found a post from Lyle Hanna in 2005 that confirms my plan will work. Just have to do it. This forum is a treasure chest. Thanks to all who share. Maybe I will be able to provide support sometime.

 

[jssailem]

The simple answer is yes. Getting the shower water out of the bilge is a smart step to improving the interior air of your boat.
There are many potential ways to pump water overboard. Care should be exercised in routing the hoses and protecting your plumbing from becoming a siphon that floods your boat.

 

[Don S/V ILLusion]

Bad idea. While it might work, it creates two problems:
1. Siphon, and
2. discharge (rate) below the waterline is inherently slow

 

[wilburleft]

Thanks for pointing out some of the risks. More research is evidently needed. The sump discharge might be stronger than the shower drain flow. But the galley sink drains fine at full on faucet…might be fine. The syphon issue though… maybe a check valve would be a workaround.

 

[Dalliance]

Thanks for pointing out some of the risks. More research is evidently needed. The sump discharge might be stronger than the shower drain flow. But the galley sink drains fine at full on faucet…might be fine. The syphon issue though… maybe a check valve would be a workaround.

A check valve would clog up pretty quick with hair and soap scum. Treat your new shower sump like an isolated bilge pump and discharge at a new through hull fitting up near the toe rail, as close as possible to the pump.

 

[MFD]

My Hunter 41DS was factory built without any sumps for the showers.

At the bottom of the drain in the shower itself is simply a 90 degree bend over to a gray water pump. Discharge is up high on the side of the hull. Probably six inches below the gunnel and same height as like the water tank and holding tank vents.

Works well and no sump pan to also collect odors or need yet another float switch or something.

on a side note, some years ago I replaced the very quiet 4-valve original pump with a whale gulper 320. Have never needed to clean a shower pump strainer since then. It’s a little loud, but also a diaphragm pump so little/no flowback. I seem to recall it’s also okay to run dry, and I definitely leave it on sucking the last bits out every shower. Am liveaboard and this setup has been trouble free for 6 or 7 years now.

 

[MFD]

Note on above - I seem to recall some actual Hunter documentation I have shows shower sump pans. My guess is that with newer pumps no long needed. Kinda like no accumulator tank for the pressure water system. Although I did install an expansion tank on the hot water side a couple months ago when I replaced the water heater. Not sure why that was not in the factory build, or how many PSI the fresh water system would get up to taking 11 gallons of water from ~50F to ~170F diesel heated temps. ‍