we also use wolvirine stick on block heaters in another boat. We installed a line voltage thermostat rated at total amp draw plus 20% in line with the heaters so that run time would be limited to the below 40* days down here. warm engine rooms are dry and keep corrosion at a minimum. block heaters for small block and most big blocks are less than 75 bucks plus the stat. but boat is an oil burner so flash points are much different than gas burners.... you could keep the thermostat outside the boat to minimize inginition risk in the bilge.

+ 1

Light bulbs work well, but I used a low wattage ceramic heater attached to a 10' piece of flexible duct work to keep my airplane preheated over the winter months. The heater was 100% solid state, and the heating element would barely get warm to the touch. I would set the heater on the ground and run the ducting under the cowl, nice warm dry engine all winter. It would fire on 3 blades every time, even at -10.

You might be able to plumb something like that into a blower vent. The air circulation is beneficial for moisture control as well.

The thermostats used in residential heaters are not explosion-proof. The little contacts in the temp control are what sparks when it turns on and off - and that's what blows up things with gas fumes in them.

Doesn't matter what kind of heating element it has, the thermostat is the culprit.

A 150 watt heatlamp bulb is far safer in comparison. If it's plugged in, it's on. If it blows out, it doesn't create a spark.

We used heatlamps for years. Put sponge type foam in the bilge vents, placed the light under the engine, and left the light on all winter.

Boatsafe makes explosion proof marine heaters with nonsparking thermostats. They are the only LEGAL ones you can use in a gas boat. Those are 400 watts, and the stat is set to like 40 degrees.

Obviously, you need to have some way of knowing whether the light is on or not, though, cause if it goes off things freeze.

Some people with boats at marinas leave a lamp on inside the boat that you can see without going into the boat. That tells whether the power is on or not but doesn't mean anything about the bulb.

Anything other than "proper winterization" is a roll of the dice.

MC

I tried the 150 watt bulb thing one year.. The same year we had the ice storm that knocked out power to our town for three days.. engines froze and busted.. An $8000 lesson on winterizing. No matter what Kind of heater you use, youre still beggine mother nature to keep the power turned on.. Winterize properly. Its cheap CHEAP securtiy.

My thoughts...DON"T DO IT! Lose power one time (Murphy's Law) and your engines are so much scrap metal.

Guys...HE IS winterizing it...

I do the light bulb thing in the spring or fall if I get cold weather after I get it out/aren't ready to put it away. I stick a small lamp on either side of the engine standing right on the fiberglass floor (60w in ea).

This spring I was a bit concerned since I ran the boat in early April and we got several long freezes after that. Just for kicks I stuck my outdoor sensor (for one of those indoor/outdoor weather deals) in the boat it got down to 26 degrees and it was rocking almost 44 in the engine bay. I did also tape off the vents.

I would never do this over the winter, but it's certainly allowed me to to get the boat out EARLY on some of those freakishly warm days....

The boat will definitely be winterized...I live in the mountains of western NC and the power is always going out. I'm just trying to do a little climate controlling in the engine room.

Oh!...shut my mouth.

You can get a dual heat range space heater that puts out 750 watts on the low setting, but the biggest risk is either the heater crapping out (which happened to me with a heater in an outside home water pump shack) or you'll be out of town when there is a power outage when the temps are super cold. I thought about doing a light bulb, but if the bulb burns out or there is a power outage, you'll shoot yourself for not "playing by the rules".