bilge backflow problems

[greasemonkeyjmj]

i have a bomber 15 foot fiberglass bassboat. the bilge is routed with a thru hull fitting, going through the transom. i am having problems with water backflowing into the thru hull and collecting in my bilge area. i have tried looping the hose and routing it as high as i can . i also went to the home improvement store and picked up a 3/4 pvc check valve. the only problem is, with the valve in place, the pump is not stout enough to push the water out through the valve. as always info is appreciated

 

[jevery]

Re: bilge backflow problems

Is the hose for the thru hull fitting connected to a bilge pump or a livewell pump? A bilge pump outlet should well above the waterline.

 

[tashasdaddy]

Re: bilge backflow problems

agree. i would plug the existing hole, and route the bilge hose to a new fitting of the drivers side of the boat, just under the rub rail, this is where they belong.

 

[greasemonkeyjmj]

Re: bilge backflow problems

Is the hose for the thru hull fitting connected to a bilge pump or a livewell pump? A bilge pump outlet should well above the waterline.

actually the the thru hull fittings for both of the pumps are in the transom, at one on each side, in the same spot, but the bilge is the only one giving me fits.

 

[greasemonkeyjmj]

Re: bilge backflow problems

agree. i would plug the existing hole, and route the bilge hose to a new fitting of the drivers side of the boat, just under the rub rail, this is where they belong.

the rub rail shows to be approx. 4 inches higher up than where the water exits now

 

[turborich]

Re: bilge backflow problems

Perhaps you could try a new bilge pump? Maybe they offer them with a built in backflow valve? Not really sure but I don't think you should need to relocate the fitting if the boat was made that way. The looping of the hose up high should have prevented this, Is the thru hull fitting submerged in the water?

Good luck.

 

[abj87]

Re: bilge backflow problems

if you want to keep the underwater discharge for the bilge you need to install a siphon breaker at the highest point in the line. Which should be as HIGH as possible in the hull.

 

[greasemonkeyjmj]

Re: bilge backflow problems

Perhaps you could try a new bilge pump? Maybe they offer them with a built in backflow valve? Not really sure but I don't think you should need to relocate the fitting if the boat was made that way. The looping of the hose up high should have prevented this, Is the thru hull fitting submerged in the water?

Good luck.

I am not sure the boat was made that way, i have found some strange things with it since i have had it.the thru hull is under water, i think what is happening is, that when i come to a stop , the waves roll into the back of the boat and flows into the bilge hose and starts a automatic siphoning action and it flows as long as i am sitting there

 

[greasemonkeyjmj]

Re: bilge backflow problems

i have never saw a siphoning breaker before, i have my hose routed just below the hatch door in the stern area, i can go much higher than where i am at. but with my boat being shallow, the hose still isnt very high up

 

[greasemonkeyjmj]

Re: bilge backflow problems

i only have a very small pump in the boat. if i went to a higher output pump, does anyone think it would push open the check valve ?

 

[jevery]

Re: bilge backflow problems

It wasn't plumbed that way origonally. Bilge pumps always outlet above the waterline. As you've noted, once the pump runs and fills the line with water it will start a siphon that will allow water back into the boat if the outlet is below the waterline. The only logical cure is to plumb it as it should be - with the outlet at least 6" or more above the waterline. Using a check valve would be trusting the seaworthyness of your boat to a small valve. If it failed and you moored somewhere, you could return to a swamped boat. Why risk it?

 

[greasemonkeyjmj]

Re: bilge backflow problems

i am waiting on engine parts to arrive right now, hopefully ill get them in and get to water test it again this weekend, if i do i may jut plug the thru hull and just route the line out where my engine harness runs and let it dump over the transon until i get a new thru hull location set up..thanks

 

[metriccrescentwrench]

Re: bilge backflow problems

What year is your Bomber? (I've got an '81 Bomber fish-n-ski).

Here's a thought. You've got 2 livewells, right? You could set up each livewell with it's own pump, each using one of the existing holes in the transom. Then put in a properly installed bilge pump with it's outlet well above the water line.

 

[abj87]

Re: bilge backflow problems

i only have a very small pump in the boat. if i went to a higher output pump, does anyone think it would push open the check valve ?

The only proper way to do it would to use a siphon breaker or the better solution would to install a new outlet several inches above the waterline. the less lines below the waterline and the less holes in the boat the better

 

[tashasdaddy]

Re: bilge backflow problems

face it who ever did it, did it wrong. my boats with live wells has 3 thru hulls in the transom.. 1. the drain plug. 2. the inlet to live well pump. 3. the drain for the live wells, in order to drain them when the boat is out of the water. the live well over flows go out thur the sides of the boat, and the bilge outlet just under the rubrail.

 

[arboldt]

Re: bilge backflow problems

Really take a look at what you've got. On my SeaRayder jet boat, there are two different systems. 1) the cockpit drains into a hose, through a check valve, and out a thru-the-hull fitting in the bottom of the boat. 2) A bilge pump routed up and out just under the rub rail.

For the cockpit drain, as you described, a sudden deceleration seems to have water gushing back in. It takes a special Sea Ray marine check valve for me; a hardware store one is spring loaded and will never get the pressure to open the valve. We've found that debris will get in that line and keep the check valve from closing completely, so I need to clean it often.

I'm sure your Bomber is very different than mine, but the way you described it sounded similar.