Marinette Boat Forum

Anyone use a "Block Heater"? Have a bilge heater with a blower that comes on 40 degrees, seems to work fine but if it were to fail things may not be good. Was looking at magnetic block heaters along with a thermo cube, a small thermostat that comes on at 35 degrees. Hopefully if the main heater failed the block heaters would come on as the temperature fell.

Are you trying to use the boat in the winter months? Anti-freeze not a better (and fail-safe) option for you?

Yes we boat year round on Lake Lanier, about 35 miles NE of Atlanta. Although temperatures here are mild for the most part from time to time they fall low enough to burst a block.

It only takes a few minutes to drain the block and manifolds down. That would be my fail safe.

You don't want to use block heaters on raw water systems. I see enough issues when they are used with antifreeze. The magnetic ones are very inefficient for the power they use.

Keep in mind, if the air temp drops to danger zone, the water temp will play a bigger role. Especially in a metal boat. I have worked on many boats in Michigan that are in 40 degree water, 10 degree outside temp, and the engine room and bilge is almost 40 degrees.

While pricey, the Xtreme bilge heaters are good ones.

http://www.xtremeheaters.com/buy

I use one in my boat and like it.

Do you monitor temps in the engine room? I've got a closed cooling system but still monitor temps. A portion of my cove froze this year but temps under the deck never dropped below 40. I'm further north in Knoxville

I don't at this point. But would love to. Looking at some options that could monitor temp and send an alert text if the temp drops below a particular level. Just have not wanted to go to some of the monthly service type of monitoring.

Block heaters and hull heaters in aluminum hull boats are about useless. I put a 750 watt hull heater in an aluminum hull houseboat with all vents sealed off. The engine compartment stayed the same temperature as the water -- not one degree warmer! Aluminum is such a good conductor that the heat from the hull heater is just transferred right into the water. They will not provide any protection.

..."Aluminum is such a good conductor that the heat from the hull heater is just transferred right into the water. "

And visa-versa. If the water at the marina never gets below 35 degrees you should be okay; it takes a long time to drop a thousand pounds of iron a few degrees.

Jeff