Modern heating options

[montigre]

Originally Posted by thinwater

I hope everyone recognizes that running an unvented heater at night while sleeping is suicidal.

There are sealed, vented propane heaters (Dickenson P9000 and P12000) that have the required safeties. These work well, are efficient, and keep the cabin dry, although they are a bit small for the OP (I have a P9000 in a 34' x 16' catamaran, and it falls behind below ~ 40F). For a live aboard, I would go with forced air.

I believe all of the Espars are vented units. Truckers use them in their sleepers IIRC.

Would the fact that you're heating a cat increase the amount of BTUs needed to effectively heat both halves? What is the energy output of propane versus diesel?

I also believe 9000 BTU would be too small, just based on prior knowledge of the needed size to heat the family's motorhome when I was a child. A 32' motorhome at sea level required 16,000 BTUs to heat to a comfortable level. I don't recall if the fuel was CNC or propane.

[mako]

How effective have any of you found the drip diesel heaters like Dickinson to be with just small cabin fans?

[Dockhead]

Originally Posted by montigre

That is true, but those other things such as lack of water when the lines are shut down and having to use some form of anti icing thingy (bubbler), etc have not changed much over the past 10 years since I last owned a boat in the area.

Electronics, heating, cooling, have all gone through leaps in evolution since then and I am out of touch with the newer items in these categories that are now available. ;-)

There are several RECENT threads on the subject -- trawling the archives will be very worthwhile, as the subject is fairly complex. Every type of heating has its own advantages and disadvantages. And good heating is the difference between joy and suffering when cruising or living aboard in cold weather. These lines written from 58 North


On my boat, which is used year round and quite far North, I use electric heat at the dock (it's usually not metered over here) and an Espar/Eberspacher 10kW hydronic system otherwise. Down to about about freezing, or at least +5C, I can keep the boat (54' monohull) reasonably warm with 3.5kW of electric heat. Below that, I have to add the Eber.

Off shore power, the Eber works pretty well. Hydronic is really good for distributing heat around a larger boat, and it makes hot water, too. The OP probably doesn't need hydronic on a boat his size, but might still be worth considering if making hot water is important. If you have space for radiators or baseboard radiators, then another advantage of hydronic is quiet.

One HUGE disadvantage of all these truck-type heaters (Webasto, Eber, etc.) is that they are fairly complex and need maintenance which is quite hard to do yourself. They do break down from time to time and can be expensive to fix. I have spent a fair amount of money on mine over the years, and have had a fair number of hassles with it. I find I need to give it professional service ($$$) every two years, and from time to time something breaks which costs me a boat unit or so. Last time it was the burner tube. On the plus side, however, it sure is nice to be able to press one button and warm up the entire boat, and make hot water.



So for a boat that size, I might seriously consider a pot-type heater like a Dickenson, Sig, etc. There are two big disadvantages of these -- first of all, you have to cut a hole in the deck for the chimney; second, they are poor at distributing heat around the boat. But they are bulletproof and can be fixed with a rusty nail. Some of them have glass burner doors and give a cheery glow when lit. A strategically placed fan might deal with the distribution issue, depending on how your boat is laid out inside.


Propane heat is very hard to do safely. As someone said, unvented propane heaters are suicide. But propane inside the boat is also extremely dangerous from the point of view of explosion. There are very few and probably only quite expensive ways to do it, which would be compliant with insurance. Also, acquiring and hauling the quantities of propane required would be a real PITA. I think diesel from your main tank is the logical fuel to use, if you're going to burn something to heat the boat.

Reverse cycle AC is also something to consider, if you have adequate shore power and if your water temperatures don't get below their efficient operating range. We used this on the last boat, and it was brilliant. If the sea is reasonably warm (admittedly this was in Florida), it uses far less power than electrical resistance heat.


As to cost of all of these variants -- it depends on a lot of variables. If you have unmetered shore power, then obviously electric heat is far cheaper than anything else. My Eber uses a liter an hour on High, which is not a trivial amount of fuel -- 24 liters a day. It will stay on High only in very cold weather, but even on Low it is using .2 liters an hour. Used continuously on Low for a month that amounts to about 150 liters. So 200 or 300 liters a month, used continuously in cold but not below freezing weather, would be a reasonable expectation. That can get pretty expensive. Fortunately in the UK you can buy diesel fuel tax free for heating, currently 69p per liter. You declare what proportion of a load of fuel you buy will be used for heating (or power generation), and that part of the load is tax free. So theoretically, it could be cheaper to heat with diesel than with electric in the UK -- 8.6p per kWH (Eber on medium, giving 3.2kW and consuming .4 l/h costing .69p/l) compared to typical 14p kWH retail cost of electrical power. YMMV in other locations.

[conachair]

Originally Posted by makobuilders

How effective have any of you found the drip diesel heaters like Dickinson to be with just small cabin fans?

Very good on a 33'er. Even without a fan, though a small computer fan helps for very little power. I have a refleks and very happy with it. No power, clean heat and clean chimney if it's working properly with a little hot plate on top for some nice winter stew bubbling away.

[mako]

Any experience with using under floor radiant heating instead of radiators?

[ranger58sb]

Originally Posted by montigre

I just purchased my cruising boat (Pearson 39) and may have to spend a couple of years living aboard in the Chesapeake area. Average winter lows are usually above freezing except for 1-2 weeks where it can become rather bitter.

What have you cold climate monohull owners used to keep the cabin warm and especially dry during the winter months that will not suffocate me or my 2 cats? Thanks.

Two of our liveaboard dock neighbor couples (two boats) just use electric heat, for the generally short-duration cold snaps.

One of those neighbors replaced an old original reverse-cycle AC/heat unit with a new one, and at the same time added a purpose-built resistance heater inserted inline somewhere so the original ducting/blower system all worked. That way they could simply close the seacock when water temps got too cold, leave the reverse-cycle units off, and still have heat from the resistance source.

These were all Dometic (CruiseAir or MarineAirrrr, I forget which, just now) units with the Vector Turbo as main... installed by Annapolis CruiseAir. I have the component numbers somewhere, if the system sounds useful to examine.

Other issues they faced had to do with pump-outs, freshwater supply, and occasional snowy docks. Our marina isn't well set up for those first two, but they made do. OTOH, there are some marinas around that would be better suited... and there are some older threads on that...

-Chris

[Dockhead]

Originally Posted by ranger42c

. . .
Other issues they faced had to do with pump-outs, freshwater supply, and occasional snowy docks. Our marina isn't well set up for those first two, but they made do. OTOH, there are some marinas around that would be better suited... and there are some older threads on that...

The best way to deal with pump outs is to go sailing. Then you can either stop off at a pumpout station or dump the tank offshore.

When living aboard, I always make it a religion to go out at least once a week, even if it's just to motor out of the harbor and drop the anchor.

In my opinion, a boat is a poor dwelling compared to a house, if you never go anywhere in it.

Winter sailing is a great joy all of its own, a completely different world.

[ranger58sb]

Originally Posted by Dockhead

The best way to deal with pump outs is to go sailing. Then you can either stop off at a pumpout station or dump the tank offshore.

Yeah... although not so easy when the marina is frozen in...



And in our area, being inland, no dumping overboard without first doing an 8 hour run (minimum) at planing speed... unless fitted with a treatment system.

There are some pump-out stations that still work during the winter, though... even though our marina's doesn't.

-Chris

[Dockhead]

Originally Posted by ranger42c

Yeah... although not so easy when the marina is frozen in...



And in our area, being inland, no dumping overboard without first doing an 8 hour run (minimum) at planing speed... unless fitted with a treatment system.

There are some pump-out stations that still work during the winter, though... even though our marina's doesn't.

-Chris

Fair enough. Sounds like a case for an ice-class steel boat

Concerning dumping overboard -- I'll make you jealous a little and tell you that in UK waters, holding tanks are not required and you can discharge directly overboard anywhere except in some marinas or near some beaches. The RYA did a huge study proving that due to strong tidal flushing all around the UK, recreational craft dumping overboard creates zero problem.

I don't even use my holding tank much, in tidal areas of Northern Europe.

The non-tidal Baltic is different, but here it's also not really a problem, as you can discharge 3 miles offshore in most countries, and there are free pumpout stations everywhere in Scandinavia.

Sorry for the thread drift.

[softdown]

Originally Posted by thinwater

I hope everyone recognizes that running an unvented heater at night while sleeping is suicidal.

There are sealed, vented propane heaters (Dickenson P9000 and P12000) that have the required safeties. These work well, are efficient, and keep the cabin dry, although they are a bit small for the OP (I have a P9000 in a 34' x 16' catamaran, and it falls behind below ~ 40F). For a live aboard, I would go with forced air.

What part of "needing fresh air" is hard to understand?

[Lepke]

Propane is an explosive gas. It's heavier than air and settles in the bilge. Meeting safety requirements doesn't make it safe. Propane detectors are only as reliable as the person maintaining it. There's a boat or two every winter that makes a bang.
Some of my favorite propane pictures...

[bcboomer]

Even if you could be sure of an uninterrupted supply of fresh air, I don't see it being practical to carry enough propane for a 2 week trip in cold weather.
The P9000 uses a 20 lb bottle in 4 days.

[thinwater]

Originally Posted by montigre

I believe all of the Espars are vented units. Truckers use them in their sleepers IIRC.

Would the fact that you're heating a cat increase the amount of BTUs needed to effectively heat both halves? What is the energy output of propane versus diesel?

I also believe 9000 BTU would be too small, just based on prior knowledge of the needed size to heat the family's motorhome when I was a child. A 32' motorhome at sea level required 16,000 BTUs to heat to a comfortable level. I don't recall if the fuel was CNC or propane.

Yes, Espars are sealed and vented if properly installed.

Heat demand depends as much on insulation and size or configuration. A motor home comparison is probably irrelevant. The best way to estimate it is to heat it up with an electric space heater at night (to eliminate solar gain). You can even do this in the summer--you just need to learn how many BTUs it takes to hold the inside 40F warmer than the outside.

Yes, 9000 BTUs is almost certainly too small. Without testing, 16K seems like a reasonable starting point.

[montigre]

This has been a very informative thread for me. I believe I will probably go with a couple of elect. space heaters or oil radiant heaters initially and may add the Dickinson for the whomping cold days. I really don't want to eat into the storage space by running courses of ductwork and I don't believe I will need too much cooling in the summers, so the system can remain on the simpler side.

I thank everyone who replied and shared their experience.

[witzgall]

If you are a full time live aboard, diesel is the only way to go if you want to be comfortable. We have three winters aboard in Annapolis, on a 44' sailboat, with two cats as well.

Electric heat will not be enough if it gets below about 20. We got here in October, and we were heating with electric. It was a cold winter, and it was NOT nice and toasty aboard. I finished a diesel hydronic installation in February, and the transformation was amazing. Diesel forced air is a distant second option for comfort and reliability.

Propane is not a dry heat, is expensive, and really only good for supplemental heat.

If you are running any type of load over 10+ amps full time, I would urge you to install a smart plug asap. Too many boats have burned because of electrical issues, and the #1 source is at the boat inlet. I know a guy who lost his boat AND his cat to a fire that started on his dock neighbors poorly maintained boat.

I recommend the Espar Mii series for hydronic, and the Webasto for forced air units. The espar Mii has two glow plugs for an increased service inerval (or failsafe if one fails) and multiple output points for efficiency. The webasto forced air is a newer design with superior diagnostic features not available on the Espar forced air.

I worked as a service manager for a company that installed and serviced both, so this advice comes from some experience other than my boat.

Chris