Heating 50ft+ boat

Rob_Webb

Rob_Webb

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Previously had a 42ft boat with 5.5KW diesel heating unit installed in aft cockpit locker with 6 outlets through boat. First 4 outlets in aft master cabin and saloon area very warm. But final 2 outlets in fwd areas much less effective resulting much cooler fwd cabin.

Our new 50 footer has master cabin fwd not aft and I want to avoid a cold master.

What’s the best solution? Moving heating unit to midships? Is that practical on a yacht? Might be a bit too noisy located near living areas?
 
Look at a Eberspacher Hydronic or equivalent. I have a 46ft Southerly with a Hydronic 10 and a forward master cabin, and have no problems keeping warm, sailing from early April to early October in the NW of Scotland.
The Hydronic is in effect a diesel powered central heating system. There is a Boiler, a water circulating pump, my case mounted aft under the cockpit, conventional plastic plumbing and 3 matrix heaters (aft cabins and aft heads, saloon, master cabin and forward heads), each controlled by a thermostat, it also heats the domestic hot water.
Although it is an effective form of heating, there are down sides, the matrix heater are quite noisy and relatively power hungry and I also question how efficient it is, when plugged in to the mains or running the generator to charge the batteries, I often run a 1 kWatt fan heater and that seems to heat the master cabin and the saloon almost as well as the Hydronic 10 (10 kWatts). The advantages are that the pipe work only needs small holes in the bulkheads, it does distribute the heat through the boat evenly and it heats the hot water.
When at anchor my morning routine is the start the generator and Hydronic 10, make breakfast, by that time everything is warm enough to get a shower and the batteries are topped up ready to go sailing.
The system is now 14 years old, so I'd hope that you could get a more efficient and quiet system now . I'd quite like to replace the matrix heaters with some which are quieter and less power hungry, but haven't been able to find any as yet.
 
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Ian_Edwards said:
Look at a Eberspacher Hydronic or equivalent. I have a 46ft Southerly with a Hydronic 10 and a forward master cabin, and have no problems keeping warm, sailing from early April to early October in the NW of Scotland.
The Hydronic is in effect a diesel powered central heating system. There is a Boiler, a water circulating pump, my case mounted aft under the cockpit, conventional plastic plumbing and 3 matrix heaters (aft cabins and aft heads, saloon, master cabin and forward heads), each controlled by a thermostat, it also heats the domestic hot water.
Although it is an effective form of heating, there are down sides, the matrix heater are quite noisy and relatively power hungry and I also question how efficient it is, when plugged in to the mains or running the generator to charge the batteries, I often run a 1 kWatt fan heater and that seems to heat the master cabin and the saloon almost as well as the Hydronic 10 (10 kWatts). The advantages are that the pipe work only needs small holes in the bulkheads, it does distribute the heat through the boat evenly and it heats the hot water.
When at anchor my morning routine is the start the generator and Hydronic 10, make breakfast, by that time everything is warm enough to get a shower and the batteries are topped up ready to go sailing.
The system is now 14 years old, so I'd hope that you could get a more efficient and quiet system now . I'f quite like to replace the matrix heaters with some which are quieter and less power hungry, but haven't been able to find any as yet.
Click to expand...
Yes, wet systems have some advantages in larger boats and assuming you are starting from scratch well worth considering.
Is there anything installed in the new boat, any ducting etc?
Siting the heater is the big issue with length of ducting versus length of exhaust playing a big part. Designing the ducting can be an art with air heaters, can some outlets be closed off to suit different crews or time of day etc?
A good start could be other owners of that model, what have they done and does it work for them.
Despite working mainly with air heaters, if! Was starting from scratch I would look at a wet system with 7 keep as my starting point.
 
Thanks for the replies so far.

The wet system is an interesting idea which I’ll look into more closely.

The question about any existing ducting - yes apparently it already has air conditioning running to all 3 cabins.

I’ve bought the boat but haven’t yet seen it - one of those Covid-driven sight-unseen purchases and obviously when the boat arrives here in NZ (hopefully within next 4-6 weeks) I’ll be able to check if the A/C is reverse cycle. If it is, that might offer a heating option of sorts but probably not as efficient as diesel heating and would probably need the genset running with it.
 
Rob_Webb said:
Previously had a 42ft boat with 5.5KW diesel heating unit installed in aft cockpit locker with 6 outlets through boat. First 4 outlets in aft master cabin and saloon area very warm. But final 2 outlets in fwd areas much less effective resulting much cooler fwd cabin.

Our new 50 footer has master cabin fwd not aft and I want to avoid a cold master.

What’s the best solution? Moving heating unit to midships? Is that practical on a yacht? Might be a bit too noisy located near living areas?
Click to expand...
Sail North until the butter melts.
 
A 'wet' eber/webasto heater which can also heat the calorifier worked well for us. Boat a bit smaller, but it's much easier to run 22mm pipes than air ducts.
The fan matrix units were a bit of a trial, noisy and power hungry. I think there are better ones on the market now.
 
Scala said:
What did you buy @Rob_Webb we were following your earlier tread with great interest....!
Click to expand...

We looked at multiple motor sailor / pilothouse options but we eventually gave up because to get the accommodation we wanted (3x double cabins including one of those as an owner’s master) we had to go too big i.e. 55ft+. Many of the 50-ish pilothouse type designs had 2x nice doubles fore & aft plus a bunk cabin somewhere - but not 3x genuine doubles.

So we ended up playing it safe and upgrading from our Jeanneau 42DS to a Jeanneau 50DS - which has the fwd master plus 2x doubles aft. Slightly boring I’m afraid but the only realistic option.

We also had to buy sight-unseen from outside NZ - still waiting for it to arrive via ship in fact - so the risk of buying a completely new design to us was too high. Hence sticking with a bigger version of a familiar design!
 
With the wet systems, is there a particular reason for choosing blown-air matrix heaters over small radiators like you’d have at home? I have seen these on a few boats so I know they’re available.

Harder to find suitable locations, I suppose?

Pete
 
Rob_Webb said:
We looked at multiple motor sailor / pilothouse options but we eventually gave up because to get the accommodation we wanted (3x double cabins including one of those as an owner’s master) we had to go too big i.e. 55ft+. Many of the 50-ish pilothouse type designs had 2x nice doubles fore & aft plus a bunk cabin somewhere - but not 3x genuine doubles.

So we ended up playing it safe and upgrading from our Jeanneau 42DS to a Jeanneau 50DS - which has the fwd master plus 2x doubles aft. Slightly boring I’m afraid but the only realistic option.

We also had to buy sight-unseen from outside NZ - still waiting for it to arrive via ship in fact - so the risk of buying a completely new design to us was too high. Hence sticking with a bigger version of a familiar design!
Click to expand...
Well that should be a known design for you, be good to see some pictures when you've taken delivery!
 
prv said:
With the wet systems, is there a particular reason for choosing blown-air matrix heaters over small radiators like you’d have at home? I have seen these on a few boats so I know they’re available.

Harder to find suitable locations, I suppose?

Pete
Click to expand...

Yes. Passive radiators are much nicer, but you need surface area -- where will you put them?

When choosing fan coils ("blown-air matrix heaters") pay attention to sound levels. Some of them are annoyingly noisy. Like mine for example. :(

Nevertheless, hydronic is the way to go on a boat that size, for all the reasons stated. I have an Eber Hydronic 12 on my boat, and it's about the right size for a 54' yacht.
 
I am just about to fit a wet system into a Beneteau 440. I have an Eber 5kw hydronic heater unit which will heat two Thermix KPH 2100 plinth heater heaters with 12v fans. I had hoped to connect it to the calorifier for hot water too, but notice that it is a single coil unit so a new twin coil calorifier now required. I had bought a diesel air heater before really looking on how to run the large bore air pipes. In the end this made me decide on the wet system rather than hot air. I will let you know how it goes.
 
mrangry said:
I am just about to fit a wet system into a Beneteau 440. I have an Eber 5kw hydronic heater unit which will heat two Thermix KPH 2100 plinth heater heaters with 12v fans. I had hoped to connect it to the calorifier for hot water too, but notice that it is a single coil unit so a new twin coil calorifier now required. I had bought a diesel air heater before really looking on how to run the large bore air pipes. In the end this made me decide on the wet system rather than hot air. I will let you know how it goes.
Click to expand...

Thanks yes please do!
 
prv said:
With the wet systems, is there a particular reason for choosing blown-air matrix heaters over small radiators like you’d have at home? I have seen these on a few boats so I know they’re available.

Harder to find suitable locations, I suppose?

Pete
Click to expand...
1) they're heavy, esp when full of water
2) they can get dangerously hot, you wouldn't want to get chucked onto one by the motion of the boat
3) they are steel so they rust and confuse the compass
4) they hold a lot of water, so you need to consider expansion vessels etc.
5) they are not easy to find space for in a medium size boat if not designed in.
6) may take a longtime to warm up.

None of this need be a show stopper, but all need thinking about IMHO.
 
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