If you are in the water, I wouldn't worry about it. Only going to be at or near freezing for a couple of hours. My water system's been flushed, and I'm still in the driveway, but I'm not sweating. Popped a heater in there, just because I plan on hitting it early in the morning.

no wories mate go down at 0330 take an ice cube place it on the top of your intake it will be turned into h2o by 0800 the water your in is warmer than a short blast of cool air

It takes time and low temperature to freeze damage things. We had 32 last night as well and none of the water in pots, or the fish pond outside, shows ice.
any

Jeff

For insurance reasons, most marinas object to any kind of electric heater 'down there'.

Jeff

I like where you are going with that Bill, but you would still have to be "down there" in order to turn it on. How about this: A high wattage light bulb, like an outdoor spotlight, in one of those aluminum industrial clamp lamps hooked up to one of those light timers that you use to fool the neighbors into thinking that you are home when you aren't. Just clamp it in the engine compartment, and set your light timer to go on at 2:00 A.M. and shut off at 6:00 A.M. That would probably put off enough heat to to keep the Ol' Girl warm, uh, "down there".. Yes?
Sean

On our 40 foot Coast Guard boats in Ketchikan we had electrically heated antifreeze systems that kept the 6-71 diesels heated to 160 degrees at all times. Easy starting, all warmed up so when the emergency calls came in, we were at full power in a few seconds. In Buffalo, NY on our tugboat in the winter we used to fill the sea chest and sea valves with oil to keep the pipes from bursting in the cold but today an air compressor supplies a small amount of air to keep the water out and no freeze burst under water pipes. Some boats today use a circulating water pump that flows water from the bottom upward to keep ice from forming around your boat. The water at its densest at the bottom is 39 degrees and this warmer water when pumped up is what does that trick. No cherry red coils that could ignite gasoline fumes, etc. were ever used.

Frankly, I wouldn't count on a bubbler system to prevent block freeze damage. That would a fatal (to the engine) leap of logic. Bubblers (either an air bubble system or a de-icer such as ones made by Kasco using a propeller) do indeed bring the warmer water to the surface to prevent icing around the hull. The air temp inside the cabin and engine compartment is going to be much closer to the ambient air temp. So, on a 15 degree day, the water around the boat will be above freezing. That's nice. Your engine block would have cracked by then. Not nice.

Sean,

How about a marriage of ideas....
- Use the hairdryer / aluminum vent pipe process (maybe with some aluminum covered fiberglass insulation <to keep heat from being transferred to salon/galley area and delivering the maximum to the engine area.> The heat, rising naturally, would then dissapate back into the galley/salon area.).

- Use a timer to control on/off cycles. Having bought my wife several of these dryers (she likes to have it running <in a safe/secure location) in the bathroom to warm up the area when she's getting ready for work), you'd need a timer that would be 110v but rated for 20 amps. This would do that: http://www.electricsuppl....com/inaircoaptih1.html . The dryer will last about 4 months before it'll wear out. And at 15.00 each, not too bad.

Still a Rube Goldberg set up but should be relatively easy to break down when you want to take the boat out on a crisp (or colder) autumn day.

Bill

I could be wrong, and usually I am, but I think a hair dryer shuts off automatically after being left on for a long time. How about the same idea but with a small ceramic heater? The ones that shut off if tipped over and put out a fair amount of heat and have an adjustable thermostat? I think they are about $30.00..
Sean

Why not add an electric flow pump on the engines coolant line to the water heater? This would keep things from freezing by using the water heater's thermostat. You can also use this setup to cool the engines after a run, which would lower the cabin temps before hitting the sack for the night (for those with a sedan)