Heating the Cockpit

ontheplane

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Hiya,

Looking at a bunch of boats now, and all around 21' ish cuddies.

None have Fresh water cooling - so I assume I can't fit normal style heating. Also the boats a bit small for an ebespatcher (I'm sure that's not how you spell it) or so I assume.

We'd like to be able to cruise 12 months with covers up, so I'm looking for a cheap and simple way to heat the cockpit.

Issues I need to address -

1) Want a dry heat to prevent us steaming up under the covers - thus probably don't want anything that is alight such as a gas burner as it is likely to produce a lot of damp heat, plus see 2 below.
2) Have small children, so don't want anything they can touch that will be hot enough to burn them.
3) Needs to be super cheap and simple to fit.

I have a 2000W inverter - so I was thinking I could run a low powered fan heater but I can only see ones that the lowest setting is 1kw which is putting a huge load on the battery even with the engine running.

I have a halogen heater that runs at 400W which is nice - but the surface metal grille does get hot enough to be a concern with kids touching it.

Anyone got any other ideas?
 
any heater running off batteries will die very quickly.


I suggest your best option is a small wood or charcoal burning stove, with a grill round it to protect small fingers. If you choose one with a 'pan' top you can use it for cockpit cooking (aka BBQ) - that will be popular ! VentilATION IN THE COCKPIT ?


e.g.
http://wildstoves.co.uk/outdoor-heaters-cookers/yurt-tent-and-caravan-stoves/



EDIT


I like the look of this one on eBay. Neat chimney, too.

http://www.ebay.co.uk/itm/SMALL-WOO...FireplacesMantelpieces_RL&hash=item3cc11b87dd
 
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Don't discount the eberspacher, its really easy to fit and can be had in petrol versions as well as diesel, £200 should buy a decent second hand example, just need a single outlet.

It could also be removed when you sell on so it's not going to be a wasted investment.
 
I wouldn't go this route to be honest with you.. imo better to think of it as camping and invest in 5 season sleeping bags, thermals etc go to the marina facilities to warm up / dry off if you need to rather than trying to make arrangement on the boat. try googling bivvy heater, the carp fishermen live in tents for days on end in 'orrible weather and I believe they have some solutions to heater a small space (not sure if the word safely comes in to it though:eek:)
 
Sorry should have been clearer - we're not going to leave the heater on whilst moored up (Have a stand-alone shorepower cable for that) this is more to use whilst pottering.

We will also not be going out to sea in the winter - it's more so we can pootle up a scenic river or something without freezing our whatsits off!

Does anyone know the output of an alternator on a standard Volvo v6 or v8 engine at little more than a tickover?
 
Alternator Output

Even at higher revolutions, the alternator will probably be rated at about 60A. This will only give a theoretical maximum of 720W at 12V which is not much to heat an uninsulated area like your canopy. Although the power would be higher if you assume 14V for a fully charged battery I think that even 720W is very optimistic. At tick-over the power would certainly be much lower.
 
If you're still looking at this segment a woodburning stove with chimney certainly would be an unconventional way to go
dokumentiplovilarabljenocranchiellipse21114.jpg



It is a matter of calculation:
Even at higher revolutions, the alternator will probably be rated at about 60A. This will only give a theoretical maximum of 720W at 12V which is not much to heat an uninsulated area like your canopy. Although the power would be higher if you assume 14V for a fully charged battery I think that even 720W is very optimistic. At tick-over the power would certainly be much lower.

See the cockpit as a tent. How many 2000w heat blowers would it take to make a 4-person tent comfortable during winter? At least 2.

4000w of heat can only reasonably be made from a petrol driven air-heater like the mentioned Eberspächer (~Webasto, Mikuni, Wallas, Thermo, Ardic, Remotron). Producing 4kW (and able to run half/full for less than freezing days) these will consume petrol and ofcourse only 12v for the fan.

By ducting you'll be able to heat the cuddy and as intake is fresh air the heated dry air will displace colder humid air hence leaving a nice and dry cabin.

Webasto Evo 3900 figures:

Fuel consumption control range 0,17 - 0,42 l/h

Nominal power consumption control range 15 - 36 W
 
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Surely running anything from an inverter let alone a 240v electric fan heater or similar whilst underway is a little dangerous ? Or am I being too cautious ? There have been similar discusions not very long ago on this forum & links to products that plumb into the engine cooling system which are like little radiators with 12v fans behind them.
 
Agree with the rest electric whilst underway is prob a non-starter. As Gary says there are some very neat small portable gas heaters about but something more permanent has got to be the Eber (or similar) route They are not that big and can be tucked away. They can be noisy though, so bear this in mind when picking where to put it.
 
Agree with the rest electric whilst underway is prob a non-starter. As Gary says there are some very neat small portable gas heaters about but something more permanent has got to be the Eber (or similar) route They are not that big and can be tucked away. They can be noisy though, so bear this in mind when picking where to put it.

If it's only for use underway, the noise shouldn't be an issue.

I'm assuming that the OP is looking to buy a boat with an outboard ?
 
The boat's inboard - but not Fresh water cooled - it's Raw Water.

From my understanding that means that you can't tap off the hot water from the engine (more than happy to be corrected on that though!)

We aren't looking to make it like a summers day in there either, just some warmth to take off the chill - if it's -5C outside we won't be on the water anyhow! BUT if it's 8 or 9 degrees, we could pop up the Bimini and turn on a bit of heat just to make the front of the cockpit a bit snugger than it would otherwise have been.

The problem I see with the Eberspächer type heaters are cost (looked on eBay and there are some 2nd hand, but I wouldn't know what I was looking for so wouldn't know if the kit was complete etc) and then fitting - as running ducting etc is perhaps a little beyond my capabilities (well to get a nice neat job anyhow).

Advantage of the Eberspächer is that you could duct some up to the windscreen and some to the floor area meaning you could certainly keep nice and warm no matter what the outside conditions, nothing to burn kiddies fingers on, and probably make the boat more desirable come re-sale as warm air heating in this country is a nice thing to have.

Advantage of the Catalytic type is cost and ease of install - however then I'd wonder how well it would work, where the heck to mount it and so on.

I did see someone posted about these little babies :- http://www.t7design.co.uk/index.php?main_page=product_info&cPath=65&products_id=189 a small heater - runs off 12V and hot water - but I am assuming that you need a Fresh water cooled engine for these to be of any use at all as I understand the water in a Raw water cooled engine never really gets that warm?

Also, if the consumption of the Eberspächer is as low as 0.15 lit per hr on low, then I could either go petrol off the main tank (vague safety concerns for me) - or much better - fit a small (10lit?) tank of diesel - and then a) it would be safer, b) It would be cheaper to run d) It could be run on low or even medium overnight fairly easily, which I am sure would make it snug enough to sleep out under the canvas even early and late season.
 
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Give a thought to overnight stays or otherwise keeping warm with engine off.

As the Eberspächer way is the recomended and usual it is the pne that heps re-sale value
 
Yes, that is certainly a + for the Eberspächer method - although given the small boat size would the noise be a problem at night?

How large is the ducting for the output warm air? Would that be relatively easy to duct round a very small boat (21' cuddy) - or will there not be much in the way of places to run it...?

Has anyone ever done one of these installs themselves and is it relatively straightforward?
 
Noise is a well known issue. Therefore you are adviced to use the silencers available for ducting and to place the burner away from cabin.

Ducting depends on model but some 75-90mm.

Check the various models. Eg Eber Airtonic B4/D4 runs in 4 powerlevel steps (automatically) and will only work as required (thermostat). So while approaching the set temp, it will go down to doing almost nothing - but still run. Very useful as to prevent repeated stop/start - which in it's turn saves power for startup procedure (glowplug heating (diesel)).
 
There is no reason why a matrix can not be used on a raw water cooled motor if tapped at the right point, I know of a couple in use, it will not be nearly as good as if it was in a closed cooling system but it will work and it's free to use.
 
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