Weather-frozen bilge pump line

[Skipper]

I had worried about this.

My bilge pump discharge line froze solid a couple weeks ago. Or that's when I noticed it. Snow-melt water had run past a seal in one of the cockpit drains (now fixed), and put a couple gallons of water in the bilge, which is below the waterline and above freezing temp. The pump triggered, and apparently tried to push bilge water through a glacier in the line, subsequently blowing the 10-amp fuse.

It's all good now, and operating correctly. But the freeze is coming again.

From what I can tell, the only way to prevent this is to put AF in the bilge and pump it into the line. The problem is that if a leak occurs below the waterline where it's not frozen (IE: shaft hose\thru-hulls\etc), the AF will be pumped out, replaced by water in the freezable line higher up. Then, the fuse will blow again, leaving the boat pumpless, and leaking.

A vented loop would still freeze on the pump side, as the diaphragm pump won't allow backflow.

Is this just a catch-22 that only serves to point to dry winter storage, or is there another remedy?

 

[Warren Milberg]

And you think you have problems.....

 

[shemandr]

Oh….my.

 

[sd1953]

Yikes!
I have a pretty dry bilge, but I have a leak somewhere on the port side of the boat that allows water in when it rains. Not much, mind you, but enough to allow evil microbes to grow. They look like an oil slick and smell like... well, they smell bad.
But y'all clearly win this one. I'm in Florida so we haven't had that much ice in this state in the last 12,000 years.
Would you be encouraged if I said, at least it doesn't smell?

 

[Bill Roosa]

If you think about it air in the bilge discharge line will only freeze when it gets to -450ish F. So take the check valve off and you should not have a problem. I would also note that if a thru hull leaks the water is above freezing and will pump fine through the bilge pump.
Also, bilge pumps are centrifugal and should not blow a fuse if they have a blocked discharge. They may run till they self destruct but they should not blow a fuse or trip a CB.
As for Warren's pic, it looks like a great way to clean the bottom half of the engine.

 

[Ron20324]

This is a good reson why check valves should be avoided. Without it, the water would just run back down into the bilge. Can you safely mount a light bulb near the freezing area for heat ???

 

[mitiempo]

If you think about it air in the bilge discharge line will only freeze when it gets to -450ish F. So take the check valve off and you should not have a problem. I would also note that if a thru hull leaks the water is above freezing and will pump fine through the bilge pump.
Also, bilge pumps are centrifugal and should not blow a fuse if they have a blocked discharge. They may run till they self destruct but they should not blow a fuse or trip a CB.
As for Warren's pic, it looks like a great way to clean the bottom half of the engine.

The op stated that the bilge pump is a diaphragm type. If he is correct the "check valves" cannot be removed. If he is incorrect and has a centrifugal pump (like a Rule) the check valve would be an addition and could be removed. The line will not freeze as long as the runs are self draining, but if a "p" trap is created by the run it will leave water in the line to freeze.

 

[slaume]

The diaphragm pump is the problem in this case.

The only way I can think of solving this is to install a small centrifugal pump for nuisance water in the winter time. It will need an automatic switch to deal with any incoming water but could be switched off is you don't want it working along with the main bilge pump. If it is installed with a vented loop and no sags in the line, there should not be a freezing problem, Steve.

 

[Ron20324]

If you, or anyone, is on the hard, you access a thru-hull from some drain line, take the hose off the fitting, run a winter-only hose from the pump, across the floor, and out the hoseless thru-hull.

Skipper, bo you know Ed on Blue Jacket (blue hull)?

 

[Skipper]

And you think you have problems.....

I suddenly feel better.

 

[Skipper]

The diaphragm pump is the problem in this case.

The only way I can think of solving this is to install a small centrifugal pump for nuisance water in the winter time. It will need an automatic switch to deal with any incoming water but could be switched off is you don't want it working along with the main bilge pump. If it is installed with a vented loop and no sags in the line, there should not be a freezing problem, Steve.

This would work, but it would constantly be cycling due to backflow. Also, this is the type of system (but with inline check valve) I just replaced with the diaphragm pump system, returning the boat to the mfg original config. There's no inline check valve now, only the pump itself which does not allow backflow.

I removed the PO's centrifical pump, and installed it in the shower sump, which, different story, I discovered that that was it's original location, as the screw holes and a hose piece lined up perfectly. Anyway, wanted to get rid of the check valve (see other posts on the subject of failure danger), and the new system works fabulously, reliably keeping the bilge empty. Except if the discharge line freezes.

The bilge sump bottom is inaccessible, and maintaining a pump down there is a nightmare, requiring special setup and PITA work, and I'd have to remove the current bilge pump switch and mounting assembly (long explanation) to put another pump down there again.

 

[Skipper]

If you, or anyone, is on the hard, you access a thru-hull from some drain line, take the hose off the fitting, run a winter-only hose from the pump, across the floor, and out the hoseless thru-hull.

Skipper, bo you know Ed on Blue Jacket (blue hull)?

That's a good remedy. Very thoughtful. This is a sailor's enginuity.

But, I'm in the water.

Is Blue Jacket a sailboat? I've not seen it.

 

[Calif. Ted]

I wonder if hanging a piece of rock salt in the bilge would act as anti-freeze ? I've left these things in the rain and they don't just melt, very hard but might be just enough to prevent freezing ?
http://horsesaltlicks.com/
Just a wild idea that struck me.
BTW Skipper, Just got a 35' slip, I'm back out on the "island".

 

[Skipper]

I wonder if hanging a piece of rock salt in the bilge would act as anti-freeze ? I've left these things in the rain and they don't just melt, very hard but might be just enough to prevent freezing ?
http://horsesaltlicks.com/
Just a wild idea that struck me.
BTW Skipper, Just got a 35' slip, I'm back out on the "island".

Hmm. Or just toss rock salt in the bilge. It wouldn't get sucked up, there's a screen at the pickup. It'll eventually dissolve, but keep the bilge water salty for awhile. Jeez that's so easy, and brilliant. Wouldn't work in the deep freeze states, but probably good for our usual temps.

By the way, we're coming back to Dana Point. Had it with the East. Putting in deposit on a 30-foot slip. Will ship the boat. Probably this fall.

 

[Gunni]

The bilge sump bottom is inaccessible, and maintaining a pump down there is a nightmare, requiring special setup and PITA work, and I'd have to remove the current bilge pump switch and mounting assembly (long explanation) to put another pump down there again.

Your goal is to keep the boat from sinking, so you don't need to have the pump at the bottom of the sump. Some kind of temporary drop in assembly could put a centrifugal deep enough to do the job, mount a remote pump switch higher and you have a pump that won't cycle when the discharge line drains down. Nothing fancy, the whole thing comes out when the happy days return. I'm thinking basket built from hardware cloth, and a hose out the dorade.

 

[Skipper]

Your goal is to keep the boat from sinking, so you don't need to have the pump at the bottom of the sump. Some kind of temporary drop in assembly could put a centrifugal deep enough to do the job, mount a remote pump switch higher and you have a pump that won't cycle when the discharge line drains down. Nothing fancy, the whole thing comes out when the happy days return. I'm thinking basket built from hardware cloth, and a hose out the dorade.

Yeah. Or could leave the centrifugal shower sump pump on; it has a float switch, too, and it's own plumbing circuit with separate discharge. The shower sump is right above the bilge sump, and still below the cabin sole. I'll remove the check valve for winter, so water won't stay in the line. If the water is that high, who cares if it constantly cycles, it's keeping the boat from taking more water till the next time I'm there, which is usually once a week.
Good suggestion. Thank you.