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Rohan · 10-12-2020, 11:03

While winterizing my sump this year the question yet again occurred to me - why?? What is the point of a shower sump pump?? I don't think it could ever be an emergency backup for the bilge pump, because if the water got that high the sump motor would be totally underwater and I don't think it would function.

Awhile back I replaced the sump motor myself, and at the time it dawned on me I could make my life easier by simply adding a filter basket and letting my shower water drain into the bilge instead. Then the bilge pump would handle it. Less complexity is a good thing. The only reason I didn't do that is because I may sell my boat someday and having a missing system would look bad.

I know some people want their bilges completely dry, but that's never the case for me. I have a keel stepped mast, and always a half inch of water down there because the bilge pump can't grab it any lower than that. Besides, I spray fresh water into the bilge every once in awhile anyway, to clear out any algae.

But at some point professional engineers decided that the sump was important enough to include, even on a budget cruiser like mine (Hunter 36), so there must be a good reason (frankly, I would have rather that same money and effort had gone toward a second back up bilge pump instead). What am I missing?

Stu Jackson · 10-12-2020, 11:06

The answer has always been that the stuff that comes off your body from a shower, if allowed to get into your bilge, is truly nasty.

Cheechako · 10-12-2020, 11:08

I have drained to bilge on my first liveaboard. I dont like it much really, steam and soapy mess in the bilge. Smells a bit like a high school gym.
My best shower solutions got rid of a sump and just had a small sea strainer and a pump in a closet under the head sink. Activate the pump with a switch in the head, sending water right overboard through an above waterline exit fitting.

Dsanduril · 10-12-2020, 11:09

Quote:

Originally Posted by Stu Jackson

The answer has always been that the stuff that comes off your body from a shower, if allowed to get into your bilge, is truly nasty.

Couple that with the soap scum in your shower water and you get a sticky, nasty mess that doesn't actually drain into the bilge sump but instead forms a snail trail along the whole drainage path and becomes unpleasantly odiferous and difficult to remove.

rslifkin · 10-12-2020, 11:09

You don't want soap scum and everything else in the bilge. It'll make the boat gross and smelly.

I have no shower sumps, just a diaphragm pump with a switch. Turn the pump on when you start the shower, turn it off when done. It just sucks the water from the drain and spews it directly overboard. Some diaphragm pumps are meant to do this with no filter, so no cleaning and it keeps things simple.

Shrew · 10-12-2020, 11:13

Because the showerpan drain is lower than or too close to the waterline to be a gravity drain system. Rather than drain into the bilge (which as stated above is not desirable) then there are only two options:

1) Electric inline pump: this must be actively turned on while showering and turned off when not.

2) Sump box with bilge pump: This allows a gravity drain into the sump box and the bilge pump inside the sump box discharges the contents overboard. This affords an 'automatic' drain option rather having the user be required to actuate a power switch to drain the shower basin.

Nobody wants grey water in their bilge. That will become a petri dish.

marshmat · 10-12-2020, 11:17

Shower drains tend to end up with a lot of hair in them. Hair clogs up centrifugal pumps, including the most common types of bilge pumps, which is something you really don't want to happen by surprise. Used shower water also has residues in it that eventually make a bit of a mess of whatever they flow over. Hence the general trend for keeping it contained to one relatively easy-to-clean area, rather than running freely through the whole bilge.

Rohan · 10-12-2020, 12:03

Quote:

Originally Posted by Cheechako

My best shower solutions got rid of a sump and just had a small sea strainer and a pump in a closet under the head sink. Activate the pump with a switch in the head, sending water right overboard through an above waterline exit fitting.

Isn't that the exact same thing as a sump pump?

Cheechako · 10-12-2020, 12:06

Quote:

Originally Posted by Rohan

Isn't that the exact same thing as a sump pump?

Yeah really I suppose, many when they use that term are talking about those plastic boxes with the tiny bilge pump in them.

Shrew · 10-12-2020, 12:12

Quote:

Originally Posted by Rohan

Isn't that the exact same thing as a sump pump?

Not really.

Sump: (Noun) A pit or hollow in which liquid collects, especially one in the floor of a mine or basement.

Any pump placed in a sump becomes a Sump Pump. The 'Shower Sump' also has a pump side. It's typically the same pump used as a Bilge Pump (when placed in the bilge). Once placed in the sump box, it becomes a sump pump.

What Cheekago is describing is simply in inline pump, where the pump is inline on the hose between the shower basin drain fitting and the through-hull discharge fitting.

No Sump, No Sump box. Therefore, not a sump pump. Put it in a bilge it's a bilge pump. Put it in a Livewell and it's a Livewell Pump.

mvweebles · 10-12-2020, 12:21

Quote:

Originally Posted by rslifkin

You don't want soap scum and everything else in the bilge. It'll make the boat gross and smelly.

I have no shower sumps, just a diaphragm pump with a switch. Turn the pump on when you start the shower, turn it off when done. It just sucks the water from the drain and spews it directly overboard. Some diaphragm pumps are meant to do this with no filter, so no cleaning and it keeps things simple.

This one. No strainer needed.

https://www.defender.com/product.jsp?id=1777934