Are engine bay heaters the right way to go and if so what size?

[philipm]

This is my first post back on this forum for 10 years during which time we have been away from boating and had a family! The latter are now old enough for us to want to get back into things and so we recently took delivery of a 2010 Jeanneau Leader 9 with 2 x Volvo D3 diesels. Effectively I'm a beginner again so there's a lot to learn!

As a result of the boat having just had a complete overhaul whilst out of the water, we don't really want to haul her out again to be winterised. That way we can have an occasional winter trip whilst the boat is still a novelty.

I am thinking tube heaters with thermostats under each engine is the way to go. I know the old scare story is "what happens if there is a power cut and your engine blocks freeze?" but I am thinking a prolonged power cut is fairly unlikely in the marina so the risk is minimal. The boat is kept on fresh water.

My main question is does this sound like a reasonable strategy and what wattage of heaters are required? I know I should also block up the vents in the engine bay whilst the heaters are there (although I can't see where the vents are).

Cheers

 

[omega2]

Why not just put anti freeze into them same as your car?

 

[Phildorset]

I opt for a tube heater (greenhouse type thingy) which is enough to keep the space a few degrees warmer than outside and always above freezing - not that it gets that cold down here in the soft southern latitudes! keeps condensation at bay too, warm (ish) and dry = v good.

 

[Mr Googler]

I bought 2 of these. One either side of the engine bay. They chuck out a good amount of heat for their size and store away easily.

VonHaus Oil Filled Radiator 6 Fin 800W Mini Electric Portable Heater - Black https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/283073247566

I will probably get away with just one in the engine bay and one inside with a dehumidifier.

It doesn’t need to keep the engine area warm.....just above freezing. It’s my understanding that boats in the water are less likely to freeze than boats out. Makes sense.....never seen my marina freeze solid.

 

[Momac]

I have tube heater in the engine bay. Sealine F33 with twin kad32's. My boat is on fresh water . A boat in the water is better protected from frost than one ashore.
The tube heater is controlled by a thermostat which records the max/min temperatures . Set to cut in at 5 degrees the temperature in the engine bay did not fall below 4 degrees last winter.
Not sure of the wattage but the tube heater is about 2 ft long.

I have the domestic water drained off and a small heater on a thermostat near the calorifier just in case some water remains in the tank.

I live within a mile of the boat so can attend at short notice if we get a real cold snap.

 

[CLB]

Why not just put anti freeze into them same as your car?

Doesn’t protect the raw water side, unless you are talking about inhibiting the raw water side with antifreeze, but this makes using the boat a hassle as you have to do it each time.

 

[philipm]

I bought 2 of these. One either side of the engine bay. They chuck out a good amount of heat for their size and store away easily.

VonHaus Oil Filled Radiator 6 Fin 800W Mini Electric Portable Heater - Black https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/283073247566

I will probably get away with just one in the engine bay and one inside with a dehumidifier.

It doesn’t need to keep the engine area warm.....just above freezing. It’s my understanding that boats in the water are less likely to freeze than boats out. Makes sense.....never seen my marina freeze solid.

Thanks all. Quite like the look of that VonHaus radiator as it looks more robust for storage than a tube heater.

A heater near the calorifier is also a good shout.

 

[Chris_d]

I wouldn't worry too much if its left in the water, I have two AD31P's that have overwintered with no heaters at all for 14 years and no adverse effects. A friend put a USB temperature logger in his engine room overwinter once, and despite many cold freezing days the recorded temperatures never dropped below freezing inside the boat. Unless your moored way up north extra heaters aren't essential.

 

[rafiki_]

I have used tube heaters for the engine room for many years, and will continue to do so, set to come on below 5c. Don’t forget your domestic water, as this is more likely to freeze. You can either drain it, but you must be very thorough, or use additional heaters inside the boat. We also use a Maeco dehumidifier to control moisture.

 

[rubberduck]

We have had tube heaters fitted on new boat, had a rad in engine room on last one but was a pain storing when not in use.

 

[omega2]

shut the seacocks, and remove the impellor, that will all drain down, might even do it with removing impellor, but not a bad idea to remove it.

 

[maverickofpoole]

Another vote for 2 no tube heaters controlled by a thermostat set at 5 deg, one under each engine plus a Meaco junior desiccant dehumidifier in the cabin area with all the internal doors including cupboards left open. The Dehumidifier not only extracts moisture from the air but also adds a little heat.

 

[QBhoy]

Always a good idea. The wee tube green house ceramic ones are low on lower demand and should fit well in the engine bay as long as they don’t touch anything. We have them fitted between the two engines on the princess and plugged into a thermostat plug socket.
BUT...I would never rely on this alone. Your engines have a closed cooling circuit with antifreeze in already. You should test the level of AF concentration with a tester and also pull the plugs out the raw water coolers that don’t have AF obviously. Easy to do.
Me being fussy, I also pull the hose off the water strainer and pour AF in and turn the engines over. This will pump AF round your raw water system and give you 100% protection and peace of mind.

 

[rlw]

Bear in mind that although the oil rad is a good option the thermostat is open and sparks so presents a risk for gassing batteries, fuel etc. I have a house type thermostat in a sealed electrical junction box that switches the tube heaters.