Block Heater

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Tuggle
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Block Heater

Postby Tuggle » Mon Jan 29, 2018 8:50 am

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.
"Deplorable", 1975 32' Express, Twin 318's, Raw Water Cooled, Lake Lanier, Ga.

jralbert
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Re: Block Heater

Postby jralbert » Mon Jan 29, 2018 12:35 pm

Are you trying to use the boat in the winter months? Anti-freeze not a better (and fail-safe) option for you?
-joel-
former owner 1988 '32 FB Sedan
Chesapeake Bay
twin 318 / 240 hp
Potomac MD

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Tuggle
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Re: Block Heater

Postby Tuggle » Mon Jan 29, 2018 1:41 pm

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.
"Deplorable", 1975 32' Express, Twin 318's, Raw Water Cooled, Lake Lanier, Ga.

TinLizzy
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Location: Lake Superior-Michigan's U.P.

Re: Block Heater

Postby TinLizzy » Mon Jan 29, 2018 7:38 pm

It only takes a few minutes to drain the block and manifolds down. That would be my fail safe.
Rodney
1975 28 Express-Twin 350 Chevy's, Raw Water cooled
Portage Canal Waterway-Upper Peninsula,Lake Superior

EWRice
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Re: Block Heater

Postby EWRice » Mon Jan 29, 2018 10:13 pm

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.
Muskegon Lake
1972 32' Express flybridge
"AL13"
Twin 318s
On board air & prime 920
1963 Thompson Super Sea Lancer
Graymarine 327
1961 Alumacraft 12'
'55 10hp Johnson

MetalHead
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Re: Block Heater

Postby MetalHead » Tue Jan 30, 2018 5:50 am

While pricey, the Xtreme bilge heaters are good ones.

http://www.xtremeheaters.com/buy

I use one in my boat and like it.
1959 Family Cruiser - Sold - Gary Dick - 12/05/14
1963 Express 31x10 - Sold - Joe & Ginger Tabor - 01/21/2017
1963 Express 31x8.5 - In Dry Dock - Restore Underway
1987 Sportsman - On Rolling Slip - Ready To Go !!!
Big BigM 's Rule !!!
Columbiana, AL

meltonhill
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Re: Block Heater

Postby meltonhill » Tue Jan 30, 2018 8:42 pm

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

MetalHead
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Re: Block Heater

Postby MetalHead » Wed Jan 31, 2018 6:19 am

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.
1959 Family Cruiser - Sold - Gary Dick - 12/05/14
1963 Express 31x10 - Sold - Joe & Ginger Tabor - 01/21/2017
1963 Express 31x8.5 - In Dry Dock - Restore Underway
1987 Sportsman - On Rolling Slip - Ready To Go !!!
Big BigM 's Rule !!!
Columbiana, AL

bpboater
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Location: Jamestown, KY

Re: Block Heater

Postby bpboater » Wed Jan 31, 2018 9:19 am

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.
1988 41 Marinette
Twin Crusader 454-350 hp closed cooling
Westerbeke 8.5 kw BTG
Lake Cumberland, KY

Fastjeff
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Re: Block Heater

Postby Fastjeff » Wed Jan 31, 2018 4:01 pm

..."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
"We live at the bottom of an ocean of air, not at the top." General Marvage Slatington