Heater for a GB 36

[Caballero II]

Some recent threads, plus my own desire fuel my interest to ask about some sort of diesel heating system for this boat. This is a cold winter for us, and my two 1500 W electric heaters are more than overwhelming my electrical capacity even at the dock. Wouldn't even be possible at anchor with out running the generator 24/7, which is not an option.

What have GB 36's that either came with factory diesel heat, or added it later, done to provide some real heat for the cabin? There is precious little available wall space to add a fuel burning heat stove, or even space for forced air outlets or hydronic heater elements. I know with the numbers of GB 36's out there, there must be a solution I haven't figured out. Love to hear your suggestions.

 

[Benthic2]

aren't you in southern California ?

 

[North Baltic sea]

Hi,

here GB boats generally diesel air blower heater Eber, webasto or Wallas Marin heater. i think the good thing about these is that they also change the air, not only heat it, it dries the air then.

Nbs

 

[Bmarler]

I have a good friend with a 36, and he’s got espar forced air. I’m not sure if the heater is in the engine room or laz. But ducting is always possible, you just need to come to grips the the big holes you will be drilling in your boat.
You can also install smaller heaters closer to point of use so ducting is easier.
For your 36, I would think two heaters would be best. One to aim at the aft cabin and rear of the salon, and one to aim forward to the forward cabin and front of salon. Each could have its own thermostat so you can have zone heating. Most 36 owners seem to not use the forward cabin as much so you can use less heat there unless it’s occupied. (My own observation, not a rule)
Air movement can drop significantly after the first duct opening, so figuring duct size and type of outlet will help tune the system for even heating.

 

[Caballero II]

aren't you in southern California ?

Yes sir, where the temp has been in the low 40's for the past couple of weeks. Also, I'm getting old.

I think the diesel heater is the way to go, but I am wondering specifically about routing of the duct work. Given that these boats are "split level" with a down fore and aft cabin, and an upper saloon in the middle, I think two units would be preferable. But I can't see exactly where I would cut the ducting to get the heat in the living space.

This is probably more of a question specifically for GB 36 owners, but TF is my "home" so this forum is my first choice for advise. I probably should get on a GB support site.

 

[RedRascal]

You probably need to think about how much heat you want to target. Such has enough heat for 3 season cruising in southern California or 4 season cruising further north. The other split is how much heat at anchor vs. the dock. If you usually tie up at a dock when cruising and plug into power then maybe a system with less BTUs would be fine because you could augment with one electric space heater on the colder trips. A smaller system equals smaller diameter duct work, fewer amps to run and a little less space for the main unit.

If your in a cold spell now you could play around with the space heaters to see what it takes to make a cabin comfortable. A space heater puts out about 5,000 BTUs of heat. Maybe the v-berth can be toasty with 1 heater or 5,000 BTUs, the aft cabin may take 1 heater on high(5,000BTUs) and a second heater on medium setting of 750watts or 2,500 BTUs. The main cabin may need 2 on high. This will give you a sense for total BTUs.

As for install if you choose the engine room, the duct runs can come out under the ladders for the fore and aft cabins. Then one or two in the main cabin via the settees.

 

[Caballero II]

You probably need to think about how much heat you want to target. Such has enough heat for 3 season cruising in southern California or 4 season cruising further north. The other split is how much heat at anchor vs. the dock. If you usually tie up at a dock when cruising and plug into power then maybe a system with less BTUs would be fine because you could augment with one electric space heater on the colder trips. A smaller system equals smaller diameter duct work, fewer amps to run and a little less space for the main unit.

If your in a cold spell now you could play around with the space heaters to see what it takes to make a cabin comfortable. A space heater puts out about 5,000 BTUs of heat. Maybe the v-berth can be toasty with 1 heater or 5,000 BTUs, the aft cabin may take 1 heater on high(5,000BTUs) and a second heater on medium setting of 750watts or 2,500 BTUs. The main cabin may need 2 on high. This will give you a sense for total BTUs.

As for install if you choose the engine room, the duct runs can come out under the ladders for the fore and aft cabins. Then one or two in the main cabin via the settees.

Good reply. We're pretty active boaters all year long. No laying up of the boat over winter, and when we're away from home port we are always at anchor and not at a dock with shore power. So, I think we want the maximum power that we would need from a diesel heater when at anchor. I don't want to run the generator to provide heat.

Even at the dock, our two 750 W electric space heaters are not quite enough in these temps. Like most, we use the forward V-berth for storage almost exclusively. I guess running the saloon ducts to under the settee is about the only option, though we use all of that for storage that would be displaced, and it all has doors. The forward berth has a fixed staircase, so I think a duct there would work. The aft stairs are removable in order to gain access to the shaft stuffing box, something I want to keep clear for emergency access. I guess the duct could run low thru the port side hanging locker and then exit through a bulkhead in the stairwell.

From what I've read, the Wallas heaters seem to get the best reviews. So, I think it would be a matter of getting a little help specifying heater and duct size.

 

[RedRascal]

Couple more thoughts on ducts, if you have a port side cabin door the step may be a place where a duct could run. Also for the aft cabin you could Y the duct run and have a small vent in the head and one routed through the hanging locker. This will reduce the size of duct work you need to run through the hanging locker if space is tight. This could work well if you leave the head door open so heat could get into the aft cabin. Plus there are usually no complaints about having heat in the head. Good luck on your search!

 

[Endeavor GB 32]

We have a 32 GB in Blaine, WA, it's our 4th GB in Puget Sound, all of which have had diesel heat. Current boat has a Webasto hot air furnace located in the lazarette, heat duct (+/- 4") runs forward outboard of starboard fuel tank, there is an outlet below the helm seat, one in the head, and one in the vee berth. T-stat is in the saloon, and there is an on/off power switch in the vee berth. Previously we have had a 46' GB that I personally installed a Webasto hot water system in, a 42' GB that I had a Webasto hot water system put in, and a 46' GB with forced air heat (too long ago to remember details.) Not aware of ever seeing a boat this size with more than one furnace unit. Our boats with hot water heat have had multiple zones with separate thermostats which is a piece of cake with hot water heat. Any thermostat calling for heat will run the circulating pump and boiler but only the fans in the zone calling for heat will run. Pretty standard set up. With hot water heat you can also have small radiators, and even a section of copper pipe below lockers to keep things dry. Hot air heat in my experience only has one thermostat and any "zoning" is accomplished with grilles with dampers. Look at the website for Sure Marine Service in Seattle, under the "heating" section. Lots of informative info there, and a phone call will get any further questions answered. On a 36 I think that either hot air or hot water would suit your needs in your location. We boat year-round but not in the last week with temps down into the single digits ;-) Good luck and we are looking forward to seeing temps in the 40's again soon!
Regards,
Scott

 

[grahamdouglass]

I have a Webasto Air Top 5000 installed in 2008. Worked flawlessly till a couple of weeks ago when it gave a code 2. This means the flame sensor doesn't work. I have burned kerosene only since its installation. Webasto is the top of the line with respect to diesel heaters but they are expensive. The Flame sensor kit with gaskets costs close to $500. On the other hand a cheap Chinese diesel heater can be had can be had for a couple of hundred dollars on Amazon. So you have a lot of choice, forced air, hydronic is your first choice. Sure Marine out Seattle gives good advice.

 

[DavidM]

Your boat has ducted A/C, right? Are they heat pump units? If they are, that would be my first recourse for heating. Even if not, it would be cheaper just to replace one or both (if that is what you have) with reverse cycle units. 16,000 btu/hr will go a long way to heat a 36' boat in 40 deg OAT.

Even if you have to upgrade your electrical to 50A to run two 16,000 btu/hr reverse cycle units, it would still be the cheapest thing to do. And reverse cycle heat, particularly at moderate sea water temps which is what you have in SoCal, should be cheaper than diesel heat.

But if that doesn't work for you, maybe you want to be warm at anchor and have no generator, then can you splice into the existing duct work. All it takes is a couple of dampers to do that and an Espar or similar forced air diesel heater should keep you warm.

David

 

[SteveK]

I have a 36 GB so my input is to ducting a diesel heater.
When I purchased the boat it was setup with an Espar which has since been replaced with a Planar 13,600 BTU.

The saloon had a 4" intake by SB door and a 4" outflow at back. Aft there was a small outflow in head and another under stairs. One out under stair FWD.
It never worked to my satisfaction as heat rises so fore and aft cabins were cool below waist line and to have them comfortable the saloon became too hot.

Solution; I eliminated intake at SB door and made the aft one into intake, this reduced ER cooling on the intake. I also made the head outflow into an intake. Fore and aft under stairs remained the same. Both intakes closer to heater as is aft cabin outflow.
Success, more even temp heat in 3 cabin spaces. Head intake draws air down low and the Saloon is heated by rising air from fore and aft. Set at 70* daytime, lower at night.
I continue to switch back/forth on which thermostat controls the burner. The aft cabin wall thermo or the internal heater thermo which works off intake air temp.

The heater is located in the rear of ER. That leaves a longer run to forward cabin. As it does not yet affect us that fore cabin is a few degree cooler than aft, I have not insulated that long run. The ER stays colder and cools said pipe so temp out fwd is less than aft. One day I will insulate and also put covers on the 4 ER vents.

 

[RedRascal]

Okay just so I have this straight, you have 1 heat outlet in the v-berth and 1 heat outlet in the aft cabin. Then two cold air returns, 1 in the aft area of the saloon and 1 in the aft head. So no heat outlet in the saloon correct?

Is the Planar variable speed/heat output and if so does it work well? Does it run on high until the boat is warm then cycles at a lower speed once the boat is up to temperature?

 

[SteveK]

Yes Red, you got it. so far this has worked for me, no heat out in saloon, just heat rising from two lower cabins with return in floor drawing air out of cabin. Of course it is still a work in progress and changes may be considered.
But removal of the hotspot in saloon was welcome. Before I could only use in unit thermo as the wall thermo kept calling for heat.
It is variable speed fan but not manual control

 

[RedRascal]

Soo, thanks for confirming. This is helpful, my buddy is thinking about heat for his CHB 34 which has a similar cabin arrangement to a GB36. Your experience will be noted.

 

[Caballero II]

Couple more thoughts on ducts, if you have a port side cabin door the step may be a place where a duct could run. Also for the aft cabin you could Y the duct run and have a small vent in the head and one routed through the hanging locker. This will reduce the size of duct work you need to run through the hanging locker if space is tight. This could work well if you leave the head door open so heat could get into the aft cabin. Plus there are usually no complaints about having heat in the head. Good luck on your search!

Thanks for this. Unfortunately, we do not have the port door option, but I think if we did a rear unit on the port side I could run the duct into the aft closet and vent it on the stairwell wall. I'm sure have some heat in the head would be nice, but leaving the head door open is a problem because that would block the bunk. Maybe a T to run a small duct into the head with a larger duct into the cabin.

 

[Caballero II]

Your boat has ducted A/C, right? Are they heat pump units? If they are, that would be my first recourse for heating. Even if not, it would be cheaper just to replace one or both (if that is what you have) with reverse cycle units. 16,000 btu/hr will go a long way to heat a 36' boat in 40 deg OAT.

Even if you have to upgrade your electrical to 50A to run two 16,000 btu/hr reverse cycle units, it would still be the cheapest thing to do. And reverse cycle heat, particularly at moderate sea water temps which is what you have in SoCal, should be cheaper than diesel heat.

But if that doesn't work for you, maybe you want to be warm at anchor and have no generator, then can you splice into the existing duct work. All it takes is a couple of dampers to do that and an Espar or similar forced air diesel heater should keep you warm.

David

David, I think you're addressing me. We do not have a/c, or any other ducts. I think I am kinda liking the hot water approach (is that hydronic?) for easier warmth distribution.

I have had 2 suggestions for Sure Marine in Seattle, so I will look into them. Thanks to all

 

[FF]

I lived aboard for 23 years mostly in the NYC area.

Temps usually run 20's at night and 30 ish days. The hassle is at tines it got well below 0F , and of course in severe winter storms electric power would go down for a couple of days to a week.

The heat question then becomes more complex .

The folks that did best used Dickinson diesel ranges or standing furnaces , gravity fed , no electric required .

Winter running the AICW or just a Norther in the Bahamas was never a hassle..

 

[canadianoil]

Navigator Stove Works

I put a wood burning stove in the aft cabin of my 1966 GB 36.

 

[Handcrafter]

Having reverse air for cooling and heating is a good choice for many if not most situations. It all depends on having electrical power. Keeping the boat in the water until end of October on north shore Lake Superior meant a few nights below freezing but a 16,000btu and 12,000btu unit kept the interior dry and at 70 degrees. At that time of year its day cruises with no anchoring out. If I added anything it would be diesel-fired hydronic heat as running piping and radiators isn't too tough. Would want a 12v dc circulating pump for the system.

 

[Caballero II]

I put a wood burning stove in the aft cabin of my 1966 GB 36.

No kidding??! That's sounds very toasty. I can't imagine where you put it.

Thanks to all for your input.

 

[Sofa King Fishy]

I installed a Chinese Park Heater with the sealed Webasto Marine exhaust/ muffler. Wrapped in fiberglass motorcycle tape. It runs off a 5g Jerry can of Diesel & keeps the boat very warm & dry. Total cost is less than $500.

 

[canadianoil]

Port side aft cabin, loose part of the single bunk

 

[HuffinandPuffin]

Hydronic

Hydronic is great because you just need to run small hoses rather than 3 - 4" ducts.

 

[Bob Jack]

+ 1 for Sure Marine. I think hydronic is the way to go. The hot water is carried through small hoses through out the boat , and to small fan radiators where the heat is required. Our original Wabasto lasted for many years, and last year we installed a new one.

 

[grandbanksbayfield]

Wood and Simplicity.

I put a wood burning stove in the aft cabin of my 1966 GB 36.

I can barely believe there is another person in this forum that has had one. We had one in our NorSea27 and loved it. It is quite a job to feed them, but they work well and you make friends quickly. People stop by just to see your stove. It was lovely while anchored in the coves of the BC coast and here during cold, rainy, summer nights in the upper reaches of the Great Lakes. A small 12V fan can move a lot of air around. Hudson Bay blankets for the night when the stove goes out.

 

[grandbanksbayfield]

Where to put it?

No kidding??! That's sounds very toasty. I can't imagine where you put it.

Thanks to all for your input.

Some of the new ones are amazingly copact.

 

[Caballero II]

Soo Valley

I have a 36 GB so my input is to ducting a diesel heater.
When I purchased the boat it was setup with an Espar which has since been replaced with a Planar 13,600 BTU.

The saloon had a 4" intake by SB door and a 4" outflow at back. Aft there was a small outflow in head and another under stairs. One out under stair FWD.
It never worked to my satisfaction as heat rises so fore and aft cabins were cool below waist line and to have them comfortable the saloon became too hot.

Solution; I eliminated intake at SB door and made the aft one into intake, this reduced ER cooling on the intake. I also made the head outflow into an intake. Fore and aft under stairs remained the same. Both intakes closer to heater as is aft cabin outflow.
Success, more even temp heat in 3 cabin spaces. Head intake draws air down low and the Saloon is heated by rising air from fore and aft. Set at 70* daytime, lower at night.
I continue to switch back/forth on which thermostat controls the burner. The aft cabin wall thermo or the internal heater thermo which works off intake air temp.

The heater is located in the rear of ER. That leaves a longer run to forward cabin. As it does not yet affect us that fore cabin is a few degree cooler than aft, I have not insulated that long run. The ER stays colder and cools said pipe so temp out fwd is less than aft. One day I will insulate and also put covers on the 4 ER vents.

So, this is a great response for me. I had not planned on any intake ducting except a short run of intake pipe needed to "balance" intake, since the ER has good fresh air access for the main engine and generator. I thought that heat air output under both fore and aft stateroom stairs would keep it simple and functional.

Do you think I'm missing something? I realize one output has to be always on, so I thought the forward berth for that. I had not thought of ducting either of the heads to provide fresh cold air to the heaters, which is also cold air when we are at rest.

So, can I avoid the fresh air intakes in the heads? I like the idea of warm air into the head, especially aft head?

 

[Caballero II]

Hydronic is great because you just need to run small hoses rather than 3 - 4" ducts.

OK, yeah. But then you have to have the space to mount radiators or some such on precious saloon/berth vertical space, especially in a GB36. Wouldn't a small hot air vent (3" or 4") require less space on a wall than a radiator apparatus? The vertical space needed is where I can least afford it.

Also, a hydronic system requires a hot water tank to supply the heat. I love the idea that could supply me with a hot water shower at anchor, but the installation sounds a little beyond what I had planned since I don't have a lot more floor space in the ER. There is some though, so I'm still listening, especially for the hot shower angle.

I may well be missing a very important part of this type of design installation. I have just very limited vertical bulkhead space that is not already consumed by drawer and locker front doors, and just a small amount of floor space left in the ER. I think I can pretty easily build a fore-and-aft bulkhead to mount the heater unit and hook it up to fuel and exhaust options.

You guys are really helping this SoCal boy out. I know this would be no problem in the NW/NE.

 

[Porgy]

Not what you’re looking for but to describe the hydronic system, we have a Hurricane. The furnace burner is surrounded by a tank full of propylene glycol which is heated and circulated to the air handlers and an expansion tank at the end. The furnace varies in size but, about 1.5’ x 1.5’ x 2’ or so. (Our former Espar was smaller and otherwise similar but without the surrounding tank. It heated coolant as it was pumped through the heater.)

The air handlers are about the size of a shoe box situated under seats or lockers with a short duct as needed to 4” round bulkhead vents. The air vent takes up no more room than forced air heaters. There are same sized return air vents elsewhere in the cabin. The system does not use water and there is no hot water tank other than the usual hot water heater. As an option you can pipe in the diesel furnace to heat your domestic hot water. I don’t know if PG has better heat transference but, should the system quit when unattended it won’t freeze and destroy itself.