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Light Bulb in Bilge Freeze Protection Data


minnmarker

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For my business we have temperature data loggers that we send along attached to some products to make sure the truckers and warehouses maintain correct temperature range. So why not use them to see what happens in the engine compartment of my Bu compared to the air outside the boat?

Here's what I found out in moderate temperatures with highs around 50 and lows around 30:

In a cold (not run for 24 hours) 21 LSV on lift under canopy with dividers in place and cover on and no heat source, the temperature in the engine compartment lags the outside air temperature by about 2 hours - so if it's below freezing for less than 2 ours you're safe.

In a 21 LSV on lift under canopy with dividers in place and cover on, a 75 watt light bulb will maintain a 7 degree temperature differential above outside air - so if it doesn't get below 25 F you're safe. I imagine a 100 watt bulb would maintain about 9 degrees.

I have a redundant system where one 75W bulb turns on at 40F using a Honeywell Winter Watchman http://www.amazon.com/gp/product/B00099DG8A?colid=1BWO1LNJ1F5MI&coliid=I4U6VDF7VH227&ref_=wl_it_dp_o_pC_nS_ttl

and a Thermo Controlled outlet turns another 75W bulb on at 35F if needed - http://www.amazon.com/gp/product/B0006U2HD2?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00

The new Winter Watchman flashes which is not ideal for heat generation. The old ones (like I have) did not flash. It's probably not too hard to wire around the flasher but I have not done it.

Bottom line:

If the low is 32 or above and lasts only a couple hours you're OK with no special preparation.

If the low is 25 or above you're OK with a 75W bulb but I would use 2 in case one burns out.

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Interesting, curious as to where exactly the bulb was placed and where the temp reading unit was placed.

Inside temp reading unit was placed by the front starboard engine mount so as to read air temp, not the temp of the metal.

Outside temp reading unit was on lift gearbox.

Light bulbs were placed as low as I could get them - on the bilge floor under the engine. Make sure there's no gas there!

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I think it's a good start as far as air temp, but agree that the block of metal is different. And, it takes a lot of energy to create the "change of state" from liquid to solid, so the that change will be pulling heat out of everything near it (ie; the engine block).

Still a good place to start though.

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The problem with this philosophy is that it only protects items in the engine compartment. Depending on where all the accessories are installed, they may still be out in the cold. And typically their plastic or aluminum & freeze damage happens sooner than with an engine block.

Edited by Bill_AirJunky
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@minnmarker Are the devices available in the retail market? Are they tied in to a custom/proprietary system that you only have access to at work? I'm interested in monitoring the temp inside my boat and it's storage locker, but have been limited by a few factors. Any information you have on self-contained temperature monitoring devices would be useful, thank you.

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Good points everyone. It is just a start. If I repeat this experiment next Fall I'll add a recorder somehow attached to the block. Yes, the block would need to loose a lot of heat to reach 32 and then make ice. A few years back I left a 4.3 Liter I/O on the lift for a 24 degree night uncovered and nothing happened to it.

For raw water loop heater cores you would need to be more cautious.

For ballast systems all my pumps are exposed to the air in the engine compartment and the other parts should be OK. Even if they're not they're relatively cheap...

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@minnmarker Are the devices available in the retail market? Are they tied in to a custom/proprietary system that you only have access to at work? I'm interested in monitoring the temp inside my boat and it's storage locker, but have been limited by a few factors. Any information you have on self-contained temperature monitoring devices would be useful, thank you.

This is what we use: http://www.logtagrecorders.com/products/trix-8.html

About $120 on Amazon for a starter kit: http://www.amazon.com/Temperature-Monitoring-Data-Loggers-LogTag/dp/B008DI45YI/ref=sr_1_3?s=industrial&ie=UTF8&qid=1445360624&sr=1-3&keywords=trix-8

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Good points everyone. It is just a start. If I repeat this experiment next Fall I'll add a recorder somehow attached to the block. Yes, the block would need to loose a lot of heat to reach 32 and then make ice. A few years back I left a 4.3 Liter I/O on the lift for a 24 degree night uncovered and nothing happened to it.

For raw water loop heater cores you would need to be more cautious.

For ballast systems all my pumps are exposed to the air in the engine compartment and the other parts should be OK. Even if they're not they're relatively cheap...

$35 for a ballast pump, x 6...... starts to hurt at some point.

What about the shower controls?

If you have a direct drive, what about the muffler? I've seen couple of them crack & their not cheap.

I have found that it's easier for me to sleep at night if I just spend a few minutes & drain everything.

I've used an indoor/outdoor thermometer from Harbor Freight. It logs high & low temps. Costs only a few bucks.

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My ballast pumps and shower system are all in the same air space as the engine. That was one of the design objectives. We think that way in Minnesota and Wisconsin!

I throw in the light bulb system if there is any chance of a freeze. Boat is 90 minutes away from home.

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Sounds like it will work for you then. I have pumps & a heater up front plus my shower controls are in the rear side compartment, none of which would never benefit.

I just don't see the point in skimping on something so important when there are safe, tried & true methods already out there. Light bulbs burn out. Bilge heaters are designed for the purpose. And draining things takes me all of 5 or 10 minutes. :dontknow:

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I bought one of these for the camper - it records high and low temp. I am going to put them in the boat this winter to see how cold it actually gets.

Boat is stored in a steel building, no heat.

http://www.amazon.com/gp/product/B001DNIIOS?refRID=JAJW7HY1VTJ4MS2YYMPT&ref_=pd_ys_c_rfy_rp_2

I've got a similar La Crosse unit. Works well but the remote unit eats up batteries. Make sure you install fresh batteries and maybe plan to replace them in January.

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I've got a similar La Crosse unit. Works well but the remote unit eats up batteries. Make sure you install fresh batteries and maybe plan to replace them in January.

Interesting, have that exact same model. Amazon says I purchased it in 2012. :) Changed batteries maybe once.

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