Tell me why this is a bad idea

[JimMann]

I have 2 sink that are now below the waterline, I have 2 spare pumps and wondered if this method was sound?

Thanks

[Singularity]

Originally Posted by JimMann

I have 2 sink that are now below the waterline, I have 2 spare pumps and wondered if this method was sound?

Thanks

Consider the pros/cons of a sump box (like a shower sump) as well as a one-way valve.

But what is the current arrangement more precisely? What are you trying to accomplish with what kind of usage?

[JimMann]

Originally Posted by Singularity

Consider the pros/cons of a sump box (like a shower sump) as well as a one-way valve.

But what is the current arrangement more precisely? What are you trying to accomplish with what kind of usage?

I just want the sink to drain automatically since it’s under the waterline

Thanks

[Discovery 15797]

A sink below the waterline???

It's not going to drain "automatically." Essentially you are draining into a very small sump, and using a pump to exhaust the water.

Essentially, your arrangement could work, but be sure to put in a vented loop well above the waterline between your pump and your outlet. I would also be sure to put a strainer/filter before the pump so any foreign objects put down the drain besides water are trapped and don't clog the pump. (If this is the route you go...perhaps consider draining into a Rule 98B shower sump.)

Practically speaking this all seems a bit strange, and pretty risky IMHO. Pump failure, float switch failure, clogged filter, etc. Seems like you're introducing problems.

Just out of curiosity...how do you get 2 sinks below the waterline in a Spray 36? (Which is a beautiful boat!)

[Zzmeyer]

Make sure you have a vented loop. If the outlet ends up below the waterline as the boat heals you will start a siphon back into the boat.

[JimMann]

Originally Posted by Discovery 15797

A sink below the waterline???

It's not going to drain "automatically." Essentially you are draining into a very small sump, and using a pump to exhaust the water.

Essentially, your arrangement could work, but be sure to put in a vented loop well above the waterline between your pump and your outlet. I would also be sure to put a strainer/filter before the pump so any foreign objects put down the drain besides water are trapped and don't clog the pump. (If this is the route you go...perhaps consider draining into a Rule 98B shower sump.)

Practically speaking this all seems a bit strange, and pretty risky IMHO. Pump failure, float switch failure, clogged filter, etc. Seems like you're introducing problems.

Just out of curiosity...how do you get 2 sinks below the waterline in a Spray 36? (Which is a beautiful boat!)

Hi,

The bathroom sink I could prob get away with as it’s borderline but the previous owner had the shower drain going into the bilge and the sink he had was very shallow but raised quite high, new sink is much deeper hence the issue. I thought I’d just run them both into an automatic pump.

I remade the kitchen in the mid of the boat due to it being too small in the pilothouse. Its very practical now and i refitted the pilothouse as our main living area but my sink was a little deeper than expected thus me being just below the line (I’m using the existing drainage holes) I was planning to put in a filter of some sort, the sink also has its own one built in as well.

I’ve seen basement system like this, just trying save money And use what I have

Thanks

[JimMann]

Originally Posted by Zzmeyer

Make sure you have a vented loop. If the outlet ends up below the waterline as the boat heals you will start a siphon back into the boat.

Ah yes, thanks for that!

[Zzmeyer]

By the way, your idea is what is on my boat, but not for the sinks but for the showers. As the drain is clearly below the waterline it drains into a grey water tank were a bilge pump type pump pumps it out. The suggestion to make sure you have an inline strainer, particularly at the sink is important.

[JimMann]

Originally Posted by Zzmeyer

By the way, your idea is what is on my boat, but not for the sinks but for the showers. As the drain is clearly below the waterline it drains into a grey water tank were a bilge pump type pump pumps it out. The suggestion to make sure you have an inline strainer, particularly at the sink is important.

I think I’ll put in a tank and do the same, makes sense

Thanks for that

[billknny]

My boat has a deep part of the bilge walled off as a "gray water sump." All showers, sinks, and incidental water drain to there where a diaphragm pump moves it overboard controlled by a float switch.

The reason is not that the sinks are below the water line, but rather it eliminates half a dozen through hulls.

It takes a pump suitable for the kind of "chunky" water that can come from a sink, and a float switch that won't clog. But with good engineering it works great.

The worst part of the arrangement is that it needs cleaning occasionally. But I'll happily trade that yucky job for the reduced number of holes in my hull!

[GILow]

I drain my shower into a big bit of Tupperware in the bilge. Inside the Tupperware container is a $20 bilge pump, a mesh strainer on the input hose and a float switch. Using the Tupperware means you get a good strong lid included to contain the smells and the whole thing is very easy to clean.

I reckon the same setup would work for the sink, but you’d have to be prepared for a pretty yucky cleaning job once a month or maybe more often.

[sailormed]

It would be wise to use a macerator pump in this setup. Less cleaning of filters and a more robust functioning. These pumps can take a lot of sh.t.

[Seriously Slow]

As long as you have a regular strainer insert in the sink I think you should consider one of these. I have one for a shower and it works great. You still want it to pump to a vented loop etc. Mine pumps to one of my cockpit drains.
It works flawlessly and I only need to clean the screen every 4 months or so.
there are lots of them available and I just chose this one from amazon as an example, not exactly what I have but they all seem to be about the same. It can also accept more than one sink hose.
https://www.amazon.com/DasMarine12V-...3254211&sr=8-4

[bailsout]

I replaced my sinks with buckets. No leaks. No blockages. Fewer thru-hulls. No maintenance.

[GeneM]

I love my whale shower sump diaphram pump. It never fails and I haven't had to clean it in two years (screens on shower drains). It comes with a water sensor so it knows when to come on.

I recommend a good pump like this for all your below water sump needs.

Ditto on the vacuum break.