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oblivionboyj · 08-03-2016, 08:12

There is currently a serviceable diesel heater in my boat.
I have considered replacing it with solid fuel.
I like the idea of heat that dries the interior rather than adds condensation.

Can you guys help me out here?
Either try and talk me out of solid fuel, or help me rationalize the change

**newhaul** · 08-03-2016, 08:27

First off a diesel heater is vented and does not add condensation to the interior of the boat. Secondly you carry lots of fuel for the heater it uses the same fuel as your mains. Third the cost of a solid fuel heater. Fourth where would you store all the fuel for the new heater for say a month on the hook. If you still want to change heat sources let me know I would like to have a crack at obtaining the diesel unit you take out.

unclemack · 08-03-2016, 08:31

I have two diesel heaters awaiting installation so I hope I'm right that you're wrong (huh?) about the condensation thing.

Portable type diesel - and propane - space heaters in workshops I've had did add moisture & cause condensation - is that what you're thinking of?

Lizzy Belle · 08-03-2016, 08:32

Not sure what kind of diesel heater you have that it adds condensation instead of dry air ... The heaters like Webasto, Eberspaecher, Wallas etc. already do exactly what you want.

The warm air goes into your boat, making it nice and warm and dry; the rest uses the exhaust or whatever the English term is (sorry

) and goes outside.

Unless you have something portable (which as far as I know wouldn't be described as 'servicable') - maybe clarify your post and let us know what make / type of heater we're talking about?

Cheechako · 08-03-2016, 08:42

If you have a bulkhead drip style diesel heater, yeah, they can be messy and moisture making. The one thing I don't like about a coal or wood heater is you cant just immediately "turn it off" in an emergency.
But right now we're guessing about what you have.....

oblivionboyj · 08-03-2016, 08:59

All liquid fuels (diesel, kerosene, propane, etc) add condensation to the heated environment, without regard to venting.
It may not be much, but if the air outside is moist it will be noticeable.

All solid fuels remove moisture from the heated environment.
A solid fuel heater reduces moisture in the air of the heated environment.
Dry is good.
The reason is the processes by witch solid and liquid fuels convert energy into heat.

The current heater is a Dickenson bulkhead diesel heater.
The idea is to replace it, in the same location, with a Dickenson bulkhead solid fuel heater.
The sale of the current would more then likely mostly finance the cost of the new.

The question of where to store the fuel is the best argument against I have heard, in general.
We would have to store the solid fuel someplace.
At this time I believe we have more than enough space for storage of the fuel.
Especially considering that the solid fuel can be stored in several locations with ease, all below deck and safe from the elements.

**Dockhead** · 08-03-2016, 09:02

Quote:

Originally Posted by newhaul

First off a diesel heater is vented and does not add condensation to the interior of the boat. Secondly you carry lots of fuel for the heater it uses the same fuel as your mains. Third the cost of a solid fuel heater. Fourth where would you store all the fuel for the new heater for say a month on the hook. If you still want to change heat sources let me know I would like to have a crack at obtaining the diesel unit you take out.

I started to answer the OP, then I read this response. I have nothing at all to add. +1!

Stu Jackson · 08-03-2016, 09:03

Two different kinds of diesel heaters: air or hydronic.

Which one do you have?

**s/v Jedi** · 08-03-2016, 09:14

A hydronic heater does NOT add humidity to the boat interior. All you circulate is hot coolant in a closed loop. I don't understand why people write such things on a forum when they don't know how it works.

Cheechako · 08-03-2016, 09:14

All I know is that, when it's cold enough to need a heater, even an electric heater adds tons of moisture to the boat interior.

**Dockhead** · 08-03-2016, 09:17

Quote:

Originally Posted by oblivionboyj

All liquid fuels (diesel, kerosene, propane, etc) add condensation to the heated environment, without regard to venting.
It may not be much, but if the air outside is moist it will be noticeable.

All solid fuels remove moisture from the heated environment.
A solid fuel heater reduces moisture in the air of the heated environment.
Dry is good.
The reason is the processes by witch solid and liquid fuels convert energy into heat.
.

This is false in several different ways.

First of all, any fuel whatsoever which is burned in a way which does not release any combustion products into the boat, will not add any moisture at all. If the combustion products do not enter the boat interior, then it makes no difference whatsoever whether you use diesel fuel, kerosene, gasoline, coal, wood, peat, or pure hydrogen.

Second of all, the amount of water vapor contained in the combustion products has nothing whatsoever to do with whether the fuel is solid or liquid. It is determined by how much hydrogen is in the fuel (whether the hydrogen is bound up in the hydrocarbons, or is present in the fuel as water, as in wood, is not important -- ALL hydrogen in fuels becomes water vapor in the process of combustion; the only hydrogen which is not converted to water vapor is whatever ends up in any unburned hydrocarbons from poor combustion).

Coal is the only commonly available fuel which has no or very little hydrogen in it. Wood actually has quite a bit of hydrogen in it, not only bound up in hydrocarbons, but also the water content of all wood. Different wood and wood at different states of dryness will have different hydrogen content, but as far as I know, ALL wood is "wetter" than diesel fuel, which is only about 14% hydrogen.

That's an academic question since you're not going to be releasing products of wood or diesel fuel combustion into the boat interior, but just to lay to rest the idea that liquid fuels produce more water vapor than solid ones. They do not!

**Dockhead** · 08-03-2016, 09:20

Quote:

Originally Posted by Cheechako

All I know is that, when it's cold enough to need a heater, even an electric heater adds tons of moisture to the boat interior.

How do you figure that? Water flows through the wires?

When you warm up any volume of air, the relative humidity falls. That's because the capacity of air to hold water vapor rises steeply with temperature. The boat should feel dryer, and the process of drying out wet things inside the boat will accelerate. Up here where I sail -- a wet, cold climate -- we use the heat as much as anything to let things dry out. Nothing more horrible than 100% humidity and wet gear (and people) below. But raise the temp even 10C, and some drying action will usually start to occur, and you will be much more comfortable.

paulajayne · 08-03-2016, 09:25

Quote:

Originally Posted by Cheechako

All I know is that, when it's cold enough to need a heater, even an electric heater adds tons of moisture to the boat interior.

No it does not.

Panope · 08-03-2016, 09:28

Panope had a wood burning heater for 18 years. The boat was warm and dry.

I swapped out the wood burning heater for a Dickinson Diesel Bulkhead heater (same as what the OP has). The boat now has exactly the same amount of moisture as when it was wood fired --- NONE ---.

Steve