Back Flow / Check Valve on Bilge hose.

amanphoto

Petty Officer 1st Class
Joined
Jun 21, 2008
Messages
336
The problem: When my boat is moving slowly threw the water (not planed off) the back of the boat is lower in the water and the nose is up. When running like this, the exit for the bilge pump is very close to the water line. If I turn right and that side of the boat goes down and water can go into the bilge exit. I have put a loop in the hose to raise it up, but I don't think its working. I think there is enough force to the water to push it up over the loop and onto my bilge. Every time I put the boat back on the trailer and remove the drain plug, tuns of water pours out.

The Fix: I want to put a Back Flow / Check Valve on Bilge hose. Does any one see any problems with this or have any suggestion on there to get one.

Note: This is the original mounting for the bilge drain. It is an 1 1/8 hole. The bilge exit is 1 1/8 barb. I need to get a solution that mates to that.

Thanks for your help
 

Yellow Yota

Petty Officer 2nd Class
Joined
Jul 23, 2009
Messages
122
Re: Back Flow / Check Valve on Bilge hose.

I see no reason why not, but are you getting enough in there to create a problem that your pump won't take care of automatically? My boat takes gallons on if you stop quickly. Comes right over the swim deck, and through the walk through. Soaks the carpet real good sometimes. I don't worry too much, because it gets pumped out if it gets too full, and the rest drains out when I get back on the trailer.
 

tractoman

Petty Officer 1st Class
Joined
Jul 16, 2009
Messages
370
Re: Back Flow / Check Valve on Bilge hose.

Has the boat always sat so low in the water? Could the water be entering from somewhere else?
 

Lion hunter

Lieutenant Commander
Joined
Apr 9, 2005
Messages
1,529
Re: Back Flow / Check Valve on Bilge hose.

What size is the hose from the bilge pump? If like most I've seen they are 5/8" or 3/4". In that case I would think that a home hose bib back flow preventor would connect in line. It would take adapters to go from 3/4" hose to 3/4" pipe, the connect with a 3/4" poly pipe barb (grey barbs) to hose to hose. Although any type of foot valve/back flow preventor will clog with debris. If the loop is below the water line then it may not do any good. The main reason for a loop is to act as a vacuum break and prevent siphoning which won't work if its below water. 1 1/8" is a huge exit.
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
71,118
Re: Back Flow / Check Valve on Bilge hose.

The Fix: I want to put a Back Flow / Check Valve on Bilge hose. Does any one see any problems with this or

Ayuh,... They're Known to Clog...
 

Philster

Captain
Joined
Sep 15, 2009
Messages
3,344
Re: Back Flow / Check Valve on Bilge hose.

I don't buy it.

When running through the water, I cannot imagine a scenario where tons of water would enter via the side through-hull fitting. Even if you are running and turning, (placing the fitting below the water line), the water is going to rush by it -- not into it. Some might enter, but that can't be all that much.

You have a loop? Well, is the loop higher up than the fitting? Based on how low the fitting is, I would have to guess that it is.

I suggest you have someone help you out, by looking into the bilge and at the tube running from the fitting in question. Have an eyewitness confirm that water is pouring into the bilge.

Also, define "tuns (sic) of water". Some people consider three pints a ton of water. Some boats drain a gallon or two and it is considered normal to the owner. How much water are we talking about?

Check with a helper while under way, and check other parts of the boat, too.

Let's say you are right, and that you are right to worry. A "clamshell" fitting placed from the front and over the outlet at at 45 degree angle front-to-rear might help.

.
 

amanphoto

Petty Officer 1st Class
Joined
Jun 21, 2008
Messages
336
Re: Back Flow / Check Valve on Bilge hose.

The hose from the pump is 1 1/8 id.

The amount of water is about 2-3 gallons.

I just bought the boat last year used. I had new bellows put on last year at a marina dealership that sells Wellcrafts.

I don't have a full loop the hose goes up from the bilge exit on the side of the boat - over a battery and down in the bilge. The total hight is about 12".

It lives on a trailer when not in the water. I can check for clogs and debris before I go out.

I'm going to put a cork or stopper in the bilge exit before I go out next and see what happens with it totally closed.
 

Lion hunter

Lieutenant Commander
Joined
Apr 9, 2005
Messages
1,529
Re: Back Flow / Check Valve on Bilge hose.

Not doubting you but I wonder why they would use an 1 1/8 hose for a bilge on a recreation size boat. I've seen trash pumps that don't use a hose that big. I would use some pipe reducers to neck down the hose to 3/4 or so so you can get a full loop in it. You can use the reducers on the hull side as well to go back up to the 1 1/8 where it exits so that you only have a few feet of smaller hose splice in.
 
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