Over the winter, if water accumulates in the bilge and then freezes around the bilge pump and/or float switch, will this damage them?
Bilge Pump and Float Switch in Frozen Water
- Thread starter asalotto
- Start date
Possibly, especially the float switch. The float is usually a couple of pieces of plastic stuck together and they are notorious for failing even when not frozen into the bilge. They would likely be susceptible to damage from ice.
If water in the bilge is a concern, then a good alternative is a garboard drain plug. This plug is put in the lowest point in the bilge and allows water to drain out. Just be certain to put the plug back in before launch.
If water in the bilge is a concern, then a good alternative is a garboard drain plug. This plug is put in the lowest point in the bilge and allows water to drain out. Just be certain to put the plug back in before launch.
That’s why people put undiluted antifreeze in the bilge. In addition to damage ice may cause, a pump switch stuck in ice will run until the pump burns up or the batteries are drained. Or both.
Never has in my experience - not once in over 15 years when the pump and float switch may have been partially or totally submerged in frozen water. Little to worry about in my opinion. Plastic ice trays do just fine in frozen water, why not a plastic part? I'm skeptical about the burned-up pump and drained battery argument. Most folks disconnect the batteries. Even if they were connected, the water would have to freeze while the pump is running - not likely. I can't envision a scenario where that would happen.
If I wasn’t out at the boat often and checking the bilge for water, I have added some (pink) AF to the bilge to make sure that any water doesn’t freeze solid.
Since I am working from home these days, I try to get out to the marina every week, and vac out any water.
Greg
Since I am working from home these days, I try to get out to the marina every week, and vac out any water.
Greg
Intuitively, that sounds correct. When we lived up north, I never thought that would be possible (to freeze pump float open and drain batteries). I still have the receipt for having to replace both when that happened to us.
As our resident philosopher often says, “Your boat, your choice”
With ice, the question is always can it expand while freezing. In an ice cube tray, the water has room to expand as it freezes. In a bilge it is a little different. A little water is probably not much of an issue, however, if pump or switch is fully submerged when it freezes solid, then it could be a problem.
Ice will always form at the surface first and gradually freeze downward because it is less dense than water. It is not hard to imagine a scenario where the float switch freezes into the on position and the bilge pump runs until the motor burns out or the batteries die and the bilge fills with water. A low spot in the bilge hose could also freeze solid blocking the hose and causing the motor to run until the bilge filled and eventually froze solid.
One technique I used to prevent damage was to put a bunch of rags and sponges in the bilge on the theory that these would absorb water and the water would freeze into the rags protecting whatever is in the bilge.
I put antifreeze in the bilge and run the pump until it comes out. The hose is almost 20' feet long and goes up and down many times before it reaches the thru-hull. Once batteries are disconnected, I disconnect the hose from the pump, put the pump above the bilge floor and put some more antifreeze in the bilge. Never had a busted hose or pump in all the years since doing that and temps do reach down lower than 20 below several times during the winter months.
I assume that you folks putting anti freeze in the bilge are using something that is somehow ok to put in the sea?
Read the SDSs before you make assumptions.
glycol type a. EC50: = 46300 mg/L, 48h(Daphnia magna)
glycol type b. EC50: > 10000 mg/L, 24h(Daphnia magna)
Based on this, type a is less toxic (more is required to be toxic). Type a is ethylene glycol. Surprised? Just because it is poisonous to cats does not make it toxic to fish (look at how HIGH those numbers are). Think about chocolate and dogs.
That PG is less toxic to marine life is misinformation that even the state sites keep re-pasting. I have contacted many for their basis, and they just say "well, that is what the others say." Fish and Wildlife list both as harmless. Google it.
That said, recycle the antifreeze. I am NOT suggesting disposal of EITHER. If you like green, salt makes a lot of sense.
If the water where the boat is sitting does not freeze, any water sitting on your bilge should not freeze either.
I leave a plastic hose in the bilge and a squeeze pump occasionally to empty any accumulated water.
@asalotto appears to be from Rhode Island. I assume most folks in R.I. store their boat in the winter on stands with the batteries disconnected. If I'm wrong about this, then the poster could clarify. The question is, WILL ice cause damage to the bilge pump and float. I'm sure it might, but in my experience, it's not likely. The bilge is nothing more than a large ice cube tray. I've never experienced any damage caused by ice in an open container. Besides that, I've never been particularly concerned about a bilge pump and float switch over the winter. There are other concerns to be had about ice in confined spaces, like pipe fittings that haven't drained, but even those locations aren't necessarily damaged by ice with 100% certainty. I have experienced a frozen engine block on a ski boat. That expense didn't bring me happiness! 
That said, my experience has generally been in locations that are not consistently frozen. In Barnegat, we rarely have the kind of ice that stays frozen throughout the winter. If there is ice in the bilge, it is generally water a week later, not that it really matters. In fact, there may be more worry about intermittent periods of ice and water, opposed to one freeze and one thaw. But, when I find ice, I can generally dry out the bottom of the bilge soon after it turns back into water. I'd suggest to @asalotto to simply look for an opportunity to empty the bilge and not worry about the pump and float. We'll probably have a stretch of warm weather soon enough.
That said, my experience has generally been in locations that are not consistently frozen. In Barnegat, we rarely have the kind of ice that stays frozen throughout the winter. If there is ice in the bilge, it is generally water a week later, not that it really matters. In fact, there may be more worry about intermittent periods of ice and water, opposed to one freeze and one thaw. But, when I find ice, I can generally dry out the bottom of the bilge soon after it turns back into water. I'd suggest to @asalotto to simply look for an opportunity to empty the bilge and not worry about the pump and float. We'll probably have a stretch of warm weather soon enough.I just purchased the boat, and it's still at the dealer till the spring. It's on the hard. The batteries are connected, as the dealer says they'll periodically run AC power to charge them over the winter. They also say "they're responsible" for it over the winter. But when I visited it last weekend, I found water in the bilge. Yes, they're "responsible", but you know how that goes. My boat, my future problem. I'll be visiting it periodically, and will empty the bilge as often as I can. It's not plastic-wrapped, but it shouldn't add too much water (I hope). Yet, there is some there now, and it was there over recent below freezing days. Thus my question. Thanks to all for your answers, and to any other thoughts you may have!
Common practice up here is to put a splash of anti freeze in the bilge and remove the batteries for the winter.
No need to remove the batteries. Just make sure they are fully charged and watered. Then completely disconnect them. Cold weather slows the self-discharge rate and as long as they are fully charged with enough water, they won't freeze.