Boat heating wish list

[Dave9111]

Regarding boat heat, don't overlook the Webasto/Espar clones coming out of China now. There are some evaluations on Youtube where they tear the units apart.
For the price, they are very hard to ignore.

[Dockhead]

Originally Posted by GILow

A very good point about fall-back. In theory at least, I will be at a marina in Tasmania with 240v power. Electricity is an expensive but practical way to heat the boat, so I guess keeping a column heater somewhere on board would be wise. I am actually looking at incorporating a 240 v heater element into the buffer tank on the basis that this would act as a backup for the diesel furnace.

Condensation is something I am worried about. I figure I'll just have to see what happens and respond accordingly. A bit of reading to do there.

The Dickinsons are very good, but it's another hole in deck for the flue... a bit of a big step....

However much it costs, I think you'll find that heating with electricity is a good deal whenever shore power is available, compared to putting hours on a diesel fired heater, unless it's a pot type heater (like a Dickenson) which never wears out and which you can service yourself.


Certainly that's what I do.

[Worthywl]

Be thoughtful about where you place your air ducts. Don’t forget the head and I would not have them in the galley toe kick. (Lessons learned with hot toes). Also keep the furnace easily accessible as they do require service. Good luck! You will love the hydronic heat!

[dleathem]

Lots of good info here. I live aboard my Cooper 416 Pilothouse in Richmond BC, which get cold and damp in the winter. My first year I used a couple of electric space heaters, which proved totally inadequate, so installed a Planar hydronic system last summer. At the moment I have 2 fan heaters installed, one with 2 switchable fans and vents, in the main salon manufactured by MSR, and a Dickenson Radex on a variable speed switch in the head. I purchased an aquastat from Sure Marine which turns on both when the coolant reaches approximately 60 deg. C. I use a standard household thermostat in the main salon to hold the temperature. I don’t run it at night, but can set the timer function for the Planar, so it’s nice and toasty when I get up. I was given a 3rd smaller MSR fan heater which I will be installing on a variable speed switch somewhere in the pilothouse/galley area.
As for condensation, I have AC so bought a household dehumidifier. It’s pretty noisy so turn on when I’m leaving the boat for a few hours, and it’s amazing the amount of moisture it sucks out of the air.
All in all I’m very happy with the setup. Doing the work myself my cost came to about $4100.00 CDN, which is pretty reasonable, and was a satisfying project.
Good luck on your project, and I loved Tasmania when I was there last March.

[Pete17C]

Radiant heat is infrared and is reflected by shiny/mirrored surfaces. Any insulation should include a reflective surface.

(didn't read the whole thread, may have been mentioned)

[wingssail]

Originally Posted by surazo

anyone is using a webasto diesel heater ? which are your opinion ? .Thanks

We used a Espar forced air diesel heater. The heat was dry and comfy. This heater works undersail as well however the amps to run it would be a problem.

After two years in PNW however we removed the Espar due to maintenance issues. Glow Pugs burned out with regularity and other problems. 15 repairs in 21 months.

Perhaps the Webasto is better.

[Auspicious]

Have you bought the kit yet?


The big advantage of hydronic is easier control of temp in various compartments and domestic hot water heating. Hydronic heat comes with a ton of hose clamps you have to keep snugged up. The big advantage of air heating is really fast warm-up of the boat and much better control of condensation.


If you can find a copy on your side of the planet I recommend "The Warm Dry Boat" by Roger McAfee.

Originally Posted by GILow

Fridge in Tassie won't be working hard, that's for sure. Fridge will be an Ozefridge, so too efficient to produce much heat waste anyway.

Air cooled or water cooled? I'm not a fan of air cooled. Water cooled is better but I really like keel-cooled.

Originally Posted by surazo

anyone is using a webasto diesel heater ? which are your opinion ? .Thanks

I have had both Webasto and Espar heaters and both installed and serviced both. I have a preference for Espar especially in the West. What else do you want to know?

[Briggers]

Originally Posted by cj88

There's a difference between closed cell foam and bubble wrap. Many incorrectly think that this foil-wrapped bubble wrap e.g. air-cell, reflectix, etc. is insulation which it is not, it is a radiant barrier. There are those that know better but continue to use the word insulation to help market it. Ask for its R-value to see how much insulation it will deliver.

I used this stuff to line my workshop, total wast of time and money. It was done when the weather was reasonably benign, the walls were then lined with ply and benches and shelves built. Winter came and I froze, now it’s up to about 26 C and I am melting.
Should have read this post first but it wasn’t here then 🥴

[wingssail]

On our 43' fiberglass sloop we installed 1/2" flexible closed cell foam on all interior hull surfaces in the living areas. The deck is balsa core and additional insulation was not required.

The boat requires 11,000 BTU if the outside temperature is below freezing.

To supply that we used an Espar D3 forced air diesel heater and an 1500watt electric heater while at the dock. These were sufficient if we closed off the unused portions of the boat. After the Espar failed and was removed we installed a bulkhead diesel drip heater with a smoke stack. It uses inside air for combustion. I jigged the diesel flow to increase the BTU from 9,000 to 11,000. I added several 12v fans to blow the heat away from the bulkhead and around the boat.

Both of these sources of diesel heat dried the boat because the products of combustion were exhausted out the stacks. The boat was warm enough with the bulkhead heater but it took a couple of hours to warm up on freezing evenings. The Espar was much faster. Coming home from work we shivered with coats on then when we went to bed it was too hot. We never left either diesel heater on while gone from the boat. One very nice thing was the warm, flickering light from the firebox on the heater. On a cold winter night that flickering firelight was always welcome. When I put on my heavy winter sweater and took a hot buttered rum outside to view the snow covered fir trees and frosty shoreline while anchored in a quiet NW cove, it was pure heaven to return below decks to the glow and warmth from that heater.

During winters we used approx. 1 gallon of fuel per day to heat the boat.

One significant problem you will run into is soot. The diesel heaters have to have precise fuel/air mixtures to burn clean. If the air is not set correctly you will wake up to a coating of soot on deck, and your neighbors will not appreciate it. You learn to watch the color of the flame. White is good, Yellow OK, Orange is dirty.

Another issue is heat while sailing. Diesel heaters rely on a good draft and the pressure of outside air while sailing is variable (wave action and flow around the sails). It is not uncommon for the reverse draft to blow out the fire in the diesel heater and then you have an instantly filled cabin with the worst smoke and unburned vaporized diesel. Relighting it is explosive!

Condensation still existed from uninsulated portions of the deck where hardware was installed. The lockers were dry because they are all wire baskets with excellent ventilation. But I will always remember one morning taking a shower and having icicles over my head from the uninsulated hatch, (Judy was warm in Florida at that time!).

We kept our system simple, as simple as possible, and we did not add plastic or other insulation to the windows or hatches. We continued to use our boat all through the winters so easily making it ready to go to sea was essential. We were not closed up in an insulated cocoon, we kept the boat looking like a boat which was still in use (it was). We also were racing so a simple and light weight heating system was important.

Now we have been in the tropics for 18 years and we don't often need the heater, but we still have our bulkhead diesel heater. Last time we used it was during winter in Richard's Bay, South Africa

[Dockhead]

Originally Posted by wingssail

We used a Espar forced air diesel heater. The heat was dry and comfy. This heater works undersail as well however the amps to run it would be a problem.

After two years in PNW however we removed the Espar due to maintenance issues. Glow Pugs burned out with regularity and other problems. 15 repairs in 21 months.

Perhaps the Webasto is better.

Bah, horrible to hear


Which model of Espar?


I just replaced last year, at great expense, a perennially troublesome Hydronic 10 with a second generation M12, and am really hoping it needs less service. So far it has been completely trouble free for a bit over one year and kept us toasty in the Arctic last summer.


The issue of servicing is a really serious question for these heaters.


If I were going to use these long term (i.e. on a boat built from scratch), I think I would:


(a) Carry a full set of spares and get competent in repairing it myself; and


(b) Set up the heating system so that two of them were installed in parallel, just like many ocean sailing boats often have two autopilots installed in parallel, backing each other up.




You could just give up and rip it all out and use a pot heater, but the problem is not only the hole in the cabin top -- it's how do you distribute the heat, especially in a larger boat. There is, I'm afraid, an awful lot to be said for these hydronic systems.

[Dockhead]

Originally Posted by Auspicious

. . . Air cooled or water cooled? I'm not a fan of air cooled. Water cooled is better but I really like keel-cooled. . .

Bit of thread drift, but I think the answer to this question depends on the latitude. In tropical and sub-tropical latitudes where the sea is hot, water cooling doesn't really work all that well -- BT, DT.


In higher latitudes with cold sea water, even when the air is hot, then water cooled (or keel cooled) is a no-brainer.


Where I sail (above 60N today), the water is rarely warmer than +6 or +7C, even if the air is +25, so my keel-cooled reefer systems (2x Isotherm SP) hardly have to cool at all -- just transfer heat to the sea, which is only a couple degrees warmer than my fridge box.

[GILow]

Originally Posted by Dockhead

However much it costs, I think you'll find that heating with electricity is a good deal whenever shore power is available, compared to putting hours on a diesel fired heater, unless it's a pot type heater (like a Dickenson) which never wears out and which you can service yourself.


Certainly that's what I do.

Dockhead, you make a very good point...

It will be interesting to do the numbers. Here in Oz power has become VERY expensive indeed, and the markup charged by the marina varies.

Actually, you've made me realise I should do the numbers on this one...

Hang on... (grabs pen and envelope)....

OK, REALLY rough figures, Diesel has around 44MJ/kg, or about 36 MJ/litre, which in Australia currently costs about AU$1.50. So that's about 4.464 cents per MJ. No idea what the furnace efficiency is though. I am going to pull a WAG and say 50%, so call it 9 cents per MJ of usable heat.

Power in Australia varies, but 37 cents per kWh is about the current domestic rate where I live, and I have heard of 40 or even 50 cents on the meters at some marinas. Using a conservative 40 cents I get...

Electrical power, 1 MJ = 0.28 kWh = 0.28 x $0.40 = 11.2 cents per MJ (Assuming 100% efficiency, reasonable enough when it comes to electrical heating.)

So, even with the horrible efficiency assumption of the diesel, at least the running costs are comparable, with diesel slightly better than electricity, BEFORE factoring in maintenance. And that maintenance is a big question as you have correctly noted.

Once I am tied to a marina again for work I will do some careful experimentation to see just how the costs really stack up. I am lucky enough to have the kind of electronics skills and equipment to make some very accurate measurements.

But that's SUPPOSED to be years away, and I plan to spend the next few years a very, very long way from mains power. So short of a really long extension lead, diesel is going to be the way to go.

[GILow]

Originally Posted by Worthywl

Be thoughtful about where you place your air ducts. Don’t forget the head and I would not have them in the galley toe kick. (Lessons learned with hot toes). Also keep the furnace easily accessible as they do require service. Good luck! You will love the hydronic heat!

Great advice, and I will heed it.

[GILow]

Oooh... sobering update.

My man on the ground (where I plan to live) just reported -5 degrees Celsius this morning.

[GILow]

Originally Posted by wingssail

On our 43' fiberglass sloop we installed 1/2" flexible closed cell foam on all interior hull surfaces in the living areas. The deck is balsa core and additional insulation was not required.

The boat requires 11,000 BTU if the outside temperature is below freezing.

According to an online calculator this is the equivalent of 3.2 kW. This is reassuring as I have 5kW at my disposal on a 42 footer.
But insulation is still something I am figuring out.

To supply that we used an Espar D3 forced air diesel heater and an 1500watt electric heater while at the dock.

AND the electric heater... ok, now we have 4.7 kW of heat, again, I have enough, but only just...

These were sufficient if we closed off the unused portions of the boat.

Noted, hence my design has three separate outlets, individually controlled. I do not expect to use the aft half of the boat unless I have visitors. And I doubt any would be crazy enough to visit me in winter in Tasmania. But there is a dedicated heater outlet for that section.

.....

Coming home from work we shivered with coats on then when we went to bed it was too hot. We never left either diesel heater on while gone from the boat.

I am currently building a programmable controller. My intention is to have the system fire up either on a timer or, ideally, by remote control from my phone. Depending on how well I insulate the storage tank this may mean anything from a 5 minute to 20 minute heat up cycle.

....

During winters we used approx. 1 gallon of fuel per day to heat the boat.

Ouch! That would get a bit expensive in Oz, but I assume you were on board full time? My plan is to be working during the day, so I should be able to shave the heating costs, at least on week days.

One significant problem you will run into is soot. The diesel heaters have to have precise fuel/air mixtures to burn clean. If the air is not set correctly you will wake up to a coating of soot on deck, and your neighbors will not appreciate it. You learn to watch the color of the flame. White is good, Yellow OK, Orange is dirty.

Another issue is heat while sailing. Diesel heaters rely on a good draft and the pressure of outside air while sailing is variable (wave action and flow around the sails). It is not uncommon for the reverse draft to blow out the fire in the diesel heater and then you have an instantly filled cabin with the worst smoke and unburned vaporized diesel. Relighting it is explosive!


I assume this is all with the Dickenson type? The Webasto has one of those blower style exhausts, so I guess the boats next to me would be the victims if the thing went sooty.

....

Thanks Wingssail, you've given me some useful metrics to consider.