Off the dock heating

[feudalkaos]

Not sure if this is the right section to post this in but it said HVAC so I am going to give it a try.

We have been living aboard at the dock for a while now and are preparing to get away from docks. This means no more (or much less often) shore power. We have relied on our reverse cycle ACs to provide heat when it gets cold.

We are currently in north eastern Florida so it doesn't get that cold that often but we do get some pretty uncomfortable cold snaps. We have easily seen in the 30s some nights in the winter.

I understands the traditional wisdom of going south in the winter to stay warmer and we would like to do that but it is not something we can do quickly or easily based on land requirements (jobs).

My question is, what are other people doing to keep their boat warm? We have a 41' boat for reference.

I have seen several different heaters (diesel, solid fuel, electric) that are available.

The electric does not seem possible because of energy usage. We are in the process of changing our batteries to a 400 amp hour lithium. I still do not see how we could run electric heaters for any useful period of time.

The other types that require a somewhat large hole in the deck to exhaust the fumes seems like overkill for a handful of weeks out of the year.

I have also seen the Wabasto Air Top heater (like the semi cabin heaters) that burn diesel. These seem like an awesome unit and would work well but they cost ~$2k or more. Again doesn't seem to make sense for a few weeks out of the year.

Anyone have any input or thoughts?

Thank you for your feedback!

[rbk]

Propane requires a smaller chimney, less finicky compared to diesels and you can probably find a couple used ones for <$1k. I say a couple as you’ll probably want two for a boat your size, one forward one aft. We run one one the center bulkhead but the V and quarter berths get cool. Make sure at least one of them have a powered fan. Wait a minute, scratch the two unit requirements, just remembered your location, one should do. I would personally probably open a port and sleep with a sheet in your cold weather lol

[clockwork orange]

There are a lot of Chinese 12v/ diesel forced air heaters available on amazon or ebay for less than $200 that are quite good. I have one of the all in one units that worked very well for occasional use last winter and a friend installed one in his 46ft sailboat to replace and old espar that was costing too much for repair parts. He used all the existing ducting from the espar. I agree that it would be hard to justify $2k for a webasto or espar but pretty easy to justify $200 for essentially the same thing.
You don't have a lot of choices if you are not willing to install a chimney through the deck as that eliminates any of the bulkhead type stoves.

[Breaking Waves]

you have covered most of the common options - two others

electric mattress pads (or blankets) are another with their own pros/cons.

We had a 'hurricane lantern' (oil lamp) and it kicked off a surprising amount of heat. edit I see it was actually called a trawler lamp - https://www.dhr.nl/dhr-decorative/pr...s/trawler-lamp

[a64pilot]

When we get caught further North than I like before heading South like this year, we do the electric blanket thing, as your going LFP that’s even more logical for you than me.
If your planning on motoring often look into a bus heater, but if your going to be on the hook, go Diesel heat.

However as your both working why are you abandoning a Marina? Working while living on the hook may be harder than you imagine and may not be worth it, if your having to go to work everyday a Marina is almost a necessity

[feudalkaos]

Originally Posted by rbk

Propane requires a smaller chimney, less finicky compared to diesels and you can probably find a couple used ones for <$1k. I say a couple as you’ll probably want two for a boat your size, one forward one aft. We run one one the center bulkhead but the V and quarter berths get cool. Make sure at least one of them have a powered fan. Wait a minute, scratch the two unit requirements, just remembered your location, one should do. I would personally probably open a port and sleep with a sheet in your cold weather lol

I did not realize the propane heaters required a smaller heater. I will have to look into that more. Thank you.

I would be inclined toward no heater also but we have kids on board as well and they tolerate the cold less well unfortunately.

[feudalkaos]

Originally Posted by clockwork orange

There are a lot of Chinese 12v/ diesel forced air heaters available on amazon or ebay for less than $200 that are quite good. I have one of the all in one units that worked very well for occasional use last winter and a friend installed one in his 46ft sailboat to replace and old espar that was costing too much for repair parts. He used all the existing ducting from the espar. I agree that it would be hard to justify $2k for a webasto or espar but pretty easy to justify $200 for essentially the same thing.
You don't have a lot of choices if you are not willing to install a chimney through the deck as that eliminates any of the bulkhead type stoves.

I saw a few of those. My big concern would be overall safety and quality. It is such a huge price different between the high end one and the cheap ones I see on ebay. Makes me wonder what is really going on. It could easily be just marketing driving the price but it could equally be a quality difference that isn't immediately apparent.

I am glad to hear that you have one and are happy with it. That is a vote toward looking into the cheap ones more.

Thank you!

[feudalkaos]

Originally Posted by Breaking Waves

you have covered most of the common options - two others

electric mattress pads (or blankets) are another with their own pros/cons.

We had a 'hurricane lantern' (oil lamp) and it kicked off a surprising amount of heat. edit I see it was actually called a trawler lamp - https://www.dhr.nl/dhr-decorative/pr...s/trawler-lamp

The electric blanket is one I am considering for sure. I havent tried it yet or done the research to determine what power consumption is there but I will explore it more.

Thanks for the link on the lamp. This could be an option but I am not sure. We have kids, a cat and a dog. If it can be knocked over, it will be on our boat.

[feudalkaos]

Originally Posted by a64pilot

When we get caught further North than I like before heading South like this year, we do the electric blanket thing, as your going LFP that’s even more logical for you than me.
If your planning on motoring often look into a bus heater, but if your going to be on the hook, go Diesel heat.

However as your both working why are you abandoning a Marina? Working while living on the hook may be harder than you imagine and may not be worth it, if your having to go to work everyday a Marina is almost a necessity

I hand't thought of a bus heater. I will look into that.

We both work from the boat we just have general location restrictions so being at a marina isn't a requirement.

[GILow]

I am using a Webasto Thermotop and a pair of heaters scrounged from two Toyota vans at the wreckers.

Total cost AU$1500, or thereabouts. What’s that, about US$1K these days?

That’s 5kW of heat, which is really the critical number in this game.

Friends had a 2kW fan type diesel heater in their 42 footer and it was not good enough for them to remain in Tasmania over winter. Probably a colder place than you are considering but keep it in mind when sizing the system.

Whatever you go with, please, please, please fit a carbon monoxide detector if you have not already. Diesel is supposed to burn without producing CO, but I’d be buggered if I’d trust any fuel burning system to behave as expected.

[a64pilot]

Oh, no Diesel absolutely combusts and forms lots of CO. In fact the Nazi’s used Diesel engine exhaust in their first gas chambers before cyanide.

[GILow]

Originally Posted by a64pilot

Oh, no Diesel absolutely combusts and forms lots of CO. In fact the Nazi’s used Diesel engine exhaust in their first gas chambers before cyanide.

Oh, right. Yes, according to Wikipedia they produce 1/28th the quantity of CO compared to a petrol engine, but that’s still too much.

I think I got the impression they did not produce CO from misunderstanding why they can be used in semi enclosed areas on forklifts etc.

Anyway, certainly the OP needs a CO detector if they go down this path, and probably should have one anyway.

[Pizzazz]

I also have kids on the boat and their needs are different. There is only one way to go, forced air diesel heater. You need the 5KW Chinese version for a boat your size and ideally you want to run hot air all the way to the vberth and the head.

Reasons:
Kids like the head/shower area to be warm
Kids have smaller body mass, and are more sensitive to temperature differences. The only way to have multi zone heating is forced air diesel heat or electric heat.
Forced air is much simpler for kids to operate (press a button) vs having kids light a diesel drip heater. Propane is no good because you run out quickly.

SV Pizzazz

[rbk]

Originally Posted by feudalkaos

I did not realize the propane heaters required a smaller heater. I will have to look into that more. Thank you.

I would be inclined toward no heater also but we have kids on board as well and they tolerate the cold less well unfortunately.

Some do. We had a force 10 with something like an 1.25” flue, open flame but vented.

[valhalla360]

If it's only occasionally, cranking up the generator to power the heat pump can be an option...not as great if you need it frequently. We've done that a few times but usually at a dock if it's really cold.