heating a small GRP cruiser (viking 23)

[magpie patrick]

The more alert amongst you may have noticed that I no longer list Lutine Bell as one of my boats - I decided last year to cut my losses, not least the aftermath of a short arm-wrestling match (more like head-butting contest) with cancer made me realise that given the choice between lodgings and that particular boat, it was no contest... Should I get another narrow boat (not impossible, indeed quite likely) it won't be a project.... 

 

Which leaves me with Juno, Viking 23, about 30 years old, basically sound - I'll be back sometime with a few questions about window seals, but she floats, is mostly rainproof, has a nice dry bilge and all the woodwork and GRP is sound. Even the electrics work...

 

But the gas system is up for replacement - replace as in put one in, I took it out because it hadn't a hope of passing the BSC, and it must be said that Juno is at present a fair weather boat. I'm not looking to live on board so no need to be equipped for arctic temperatures and snow drifts, but something to take take the edge off the cold would be of benefit, and whilst I could run the cooker and the oven (when fitted) to warm the cabin up this might not be the most efficient or safest way to do this...

 

So how does one warm up the cabin? It never had a heater, just hot water and a cooker

 

Also, any views on spirit stoves? They look a bit dodgy to me for BSS and I guess they don't heat water, just the cooker...  but it has been suggested...

 

 

[JamesFrance]

If you have a mains supply this one runs on gas or 240v. https://www.propexheatsource.co.uk/heaters/hs2000e

I had a spirit cooker on a sailboat once and they will boil a kettle but not for serious cooking.

[LadyG]

The only way, imho is a heating system that vents to the exterior, using the gas oven as a heater will knock you off your perch.

I had a 30ft sailboat with a very small Taylor diesel stove, I think it needed tlc., there is also a Tiny s/f stove, see youtube - RV's, and tiny homes, try Slim Potatohead Stove

Edited March 2, 2020 by LadyG

[magpie patrick]

6 minutes ago, LadyG said:

The only way, imho is a heating system that vents to the exterior, using the oven as a heater will knock you off your perch.

I've done it in the past but I woudn't risk nodding off when using the cooker or oven as a heater!

 

7 minutes ago, JamesFrance said:

I had a spirit cooker on a sailboat once and they will boil a kettle but not for serious cooking.

Thanks, I suspected as much

[Alan de Enfield]

We had a Propex in a Horse trailer (in the living section) it was perfect and produced plenty of heat - HOWEVER, the exhaust vents thru the floor (not ideal in a boat) but there is a marine conversion kit for them so if you buy one make sure you get the marine version / kit.

 

They do require a 12v supply for the blower and are quite heavy on 12v consumption (something like 2 amps continuous) so you need to make sure your battery bank / recharging can cope with the additional demand.

[mrsmelly]

We had a fab wooden boat a few years ago. It was heated with a Taylors heater. They look good and do a good job.

[magnetman]

Tiny wood stoves are an option. There are some very small French stoves which are properly made and will work with a 2 inch flue. Will need regular cleaning. 

 

Taylor's as mentioned diesel or paraffin are ok. I'd prefer the diesel. 

 

Refleks 66 is an amazing heater but quite costly and 70mm diameter flue plus you do need to have the correct external terminal or it will blow out. 

 

There is a small LPG heater which has a 1" flue pipe. Properly made thing I have used one and it does vent the moisture through the little chimney.  Quite a rare item in the UK it's called the Cosy Cabin heater. 

 

Then there are the Newport heaters including a tiny little bulkhead mounted unit which will burn small pieces of wood.

 

Diesel is the best as it gives a long burn and dry heat. 

 

I've had a Refleks 66 burning non stop on one of my boats since October and it has not once been blown out. A very impressive little heater that is. 

 

 

 

 

Edited March 2, 2020 by magnetman

[LadyG]

1 hour ago, Alan de Enfield said:

We had a Propex in a Horse trailer (in the living section) it was perfect and produced plenty of heat - HOWEVER, the exhaust vents thru the floor (not ideal in a boat) but there is a marine conversion kit for them so if you buy one make sure you get the marine version / kit.

 

They do require a 12v supply for the blower and are quite heavy on 12v consumption (something like 2 amps continuous) so you need to make sure your battery bank / recharging can cope with the additional demand.

 

1 hour ago, Alan de Enfield said:

We had a Propex in a Horse trailer (in the living section) it was perfect and produced plenty of heat - HOWEVER, the exhaust vents thru the floor (not ideal in a boat) but there is a marine conversion kit for them so if you buy one make sure you get the marine version / kit.

 

They do require a 12v supply for the blower and are quite heavy on 12v consumption (something like 2 amps continuous) so you need to make sure your battery bank / recharging can cope with the additional demand.

I have one, which I dont use, gas fitter due in two weeks, I have only a vague idea how they work, there is a thermostat and there is a gas feed to a green box.

[Alan de Enfield]

3 minutes ago, LadyG said:

 

I have one, which I dont use, gas fitter due in two weeks, I have only a vague idea how they work, there is a thermostat and there is a gas feed to a green box.

Connect it to the gas

Connect it to the battery

Switch onto 'heat' on the 3-position switch

Turn thermostat up until it starts to blow, listen for the 'clicks' as it fires

Feel vent for heat output

Adjust thermostat to desired temp.

 

 

[Philip]

My Norman 24 has, in effect, 3 heating sources. Main piece of equipment is a Propex blown-air heater, which vents from the outside. It is a first-gen model so better versions out there, but it's good enough for its job and has been reliable over the last 7 years. Also have a car-heater style unit taken off the calorifier pipe from the inboard engine; very pleased with it as it is free heat. Not quite as powerful as the Propex, but it's a very handy thing to have running whilst out cruising - makes the cabin reasonably pleasant to go into after stopping for the day! Also have an 'army' sleeping bag which is effective enough to not need to run the heating on a cold night.

[Mad Harold]

A blown air diesel or gas heater is the usual way to heat a grp boat.They take very little space and are easy to fit,remembering that they must exhaust and draw their combustion air to outside.

Propex,Eberspacher,Webasto are the most common.

Dare not mention Chinese diesel heaters for fear of getting my head bitten off .

[WotEver]

57 minutes ago, Mad Harold said:

Dare not mention Chinese diesel heaters for fear of getting my head bitten off .

By whom?  Lots of folk on here have the cheap Chinese heaters, but you do have to upgrade the fuel line and the exhaust. 

[jocave]

Eberspacher or the cheaper  Chinese equivalent is the perfect solution to your needs , the Eberspacher on my Viking warmed it up in minutes and kept it warm all night and used hardly any diesel and was pretty battery friendly when I was out and about, I will fit one in my next boat if it doesn't already have one..

Edited March 2, 2020 by jocave

[Alan de Enfield]

38 minutes ago, jocave said:

Eberspacher or the cheaper  Chinese equivalent is the perfect solution to your needs , the Eberspacher on my Viking warmed it up in minutes and kept it warm all night and used hardly any diesel and was pretty battery friendly when I was out and about, I will fit one in my next boat if it doesn't already have one..

 

Blown air Eberspacher (etc) heaters are pretty high users of power, they are very different to 'water heaters'.

My blown air Eberspacher uses a constant 10 amps (240Ah per day)

 

115 watts continuous, 330 watts start up.

 

 

[Momac]

Some advice on the following

https://www.letonkinoisvarnish.co.uk/eberspacher_voltage_1.html

 

in a small boat a D2 heater would be sufficient - best run these things hard rather than over size and run them gently.

I think the amps required will be under 10A on start up and half that when the glow plug cuts out - note more electrical energy also required when shutting down.

 

[jocave]

10 hours ago, Alan de Enfield said:

 

Blown air Eberspacher (etc) heaters are pretty high users of power, they are very different to 'water heaters'.

My blown air Eberspacher uses a constant 10 amps (240Ah per day)

 

115 watts continuous, 330 watts start up.

 

 

He wouldn't need a d8 on a tiny boat like the Viking, a d2 is more than enough , on mine it was only ever ran on low ..

[Alan de Enfield]

4 minutes ago, jocave said:

He wouldn't need a d8 on a tiny boat like the Viking, a d2 is more than enough , on mine it was only ever ran on low ..

Yes I know (mine is a 36 footer with 6 outlets in 5 cabins) but it was the principle that folks used to 'water' Eberspachers may not be au-fait with the amount of leccy a 'blown air' system uses.

 

Even the tiny 'Propex' use about 2 amps so more than running a 12v fridge

Edited March 3, 2020 by Alan de Enfield

[magpie patrick]

It sounds like blown air heaters may require a complete overhaul of the electrical system! Not impossible, but it wasn't on my agenda. Historically Juno has had a starter battery for the engine and one leisure battery for the domestics. Given the engine is a 10hp Yamaha charging batteries when under way is limited.

 

Thanks for all the information - I shall ponder. It's not as if I've got anything else to do in 2020

[Mad Harold]

Don't think a complete overhaul of your electrics is necessary.

A seperate cicuit from the battery  and an isolation switch in the cicuit (for emergency stop) is all thats needed.A line fuse for the heater cicuit is also a good idea.

On a previous post A De Enfield and Jen in Wellies posted a link to a ready reckoner to calculate diameter of wiring needed this is important because of voltage drop.

A small solar panel will help keep your battery topped up.My boat has a 10w one ,and as a weekender the battery is usually fully charged when I visit the boat.

 

 

[WotEver]

1 hour ago, Mad Harold said:

On a previous post A De Enfield and Jen in Wellies posted a link to a ready reckoner to calculate diameter of wiring needed

Or just do some simple maths:

cablesize in mm² = 18*metres*amps/(V*1000)

Distance is there and back, so twice the distance from battery to appliance. 
 

 

Edited March 4, 2020 by WotEver
Added a bit

[WotEver]

Or for short distances up to 3m a really rough ready reckoner would be to just do A/3.
So 30A would require 10mm² cable using this method. 
 

 

Edited March 4, 2020 by WotEver
Autoincorrect

[magpie patrick]

Noted on the cabling but how long is one 110ah leisure battery going to run a blown air heater for? 

[ditchcrawler]

1 minute ago, magpie patrick said:

Noted on the cabling but how long is one 110ah leisure battery going to run a blown air heater for? 

I think that may be the problem

[Alan de Enfield]

44 minutes ago, magpie patrick said:

Noted on the cabling but how long is one 110ah leisure battery going to run a blown air heater for? 

That was the point I was trying to make - its no use just adding another battery to the bank as you still have to find a way of pouring some amps back into it.

[ditchcrawler]

1 minute ago, Alan de Enfield said:

That was the point I was trying to make - its no use just adding another battery to the bank as you still have to find a way of pouring some amps back into it.

If Magpie is not going to live aboard then maybe a second battery and some solar panels on the cabin roof may help if he only wants limited heating on the cooler evenings