Gas versus spirit

[Otter]

Would be interesting to correlate to size of boat. Suspect that break point would be around 24/25' which is where boats are more likely to be used for longer periods and be big enough to fit a proper gas system. This may of course also correlate with the original proposition of inshore/offshore.

34' and 10 weeks a year cruising. Spirit hob is a bit slower, oven definitely slower, but we're on holiday and try not go be in a hurry to eat, pop the potatoes and pie in the oven en route and eat leisurely on arrival.

 

[NornaBiron]

better a gas cooking stove and a Refleks heater with one ring on top

Our set up exactly, it works very well, even giving us hot water from the Refleks.

 

[ghostlymoron]

Not many households use anything other than gas or leccy. Leccy not available on boats so use gas.

 

[Kelpie]

But a lot of houses use heating oil. Which is the same as paraffin.

 

[Tranona]

34' and 10 weeks a year cruising. Spirit hob is a bit slower, oven definitely slower, but we're on holiday and try not go be in a hurry to eat, pop the potatoes and pie in the oven en route and eat leisurely on arrival.

You sound like a candidate for a Taylors. Still (IMHO) the best once you get used to it.

 

[aquaplane]

I'm going to have to put a test on. The Origo is a bit slower than gas but I believe there is much less difference than you would think listening to folk on here.

I'll time boiling a pint of water on each stove and get some numbers, it'll take a while though.

 

[andygc]

I wonder how many of those commenting have tried both gas and spirit. I have. If I had a big boat with many mouths to feed, it would have to be gas in order to have a big enough stove. In my wooden 27 footer with limited space in the ends and a small galley, spirit makes sense from its lack of complexity, safety and ease of use. I've nowhere for a gas locker away from the cooker and anyway there isn't the freeboard for a gas vent at the bottom of a locker and above the waterline, but I've plenty of space for 5 litre bottles of alcohol. Toast isn't a problem if you are happy to cook one slice at a time, the kettle boils plenty quick enough, and we manage a three-course meal for two with no difficulty.

I am curious about the claim early in the thread that a Primus blew up. If it was a paraffin stove it couldn't blow up, but it could certainly make a very large plume of yellow flame if not pre-heated correctly.

 

[maby]

A colleague insists that gas is only rarely fitted on offshore boats, most cookers using spirit.

Can anyone give a guess as to the ratios? He needs to be corrected!

Isn't the critical word here "offshore"? Gas is vastly more convenient, but liquid fuels have a far higher energy density which may be important if you are expecting to spend many weeks at sea.

 

[AngusMcDoon]

Isn't the critical word here "offshore"? Gas is vastly more convenient, but liquid fuels have a far higher energy density which may be important if you are expecting to spend many weeks at sea.

Hmm...

Methylated spirits as a fuel

The energy released from burning ethanol is approximately 30 kJ/g. For comparison, the energy released during the combustion of propane and butane are about 50 kJ/g and 49 kJ/g respectively.

 

[Kelpie]

Isn't the critical word here "offshore"? Gas is vastly more convenient, but liquid fuels have a far higher energy density which may be important if you are expecting to spend many weeks at sea.

Not all liquid fuels are created equal!
Energy density of alcohol is considerably less (40% or so) than paraffin. I'm not sure how gas stacks up but obviously it can only be stored in dedicated lockers for safety so there is a limit on how many bottles you can carry.
Annoyingly, with paraffin you end up carrying alcohol anyway for pre-heating, as I for one cannot be bothered standing holding a blowtorch for two minutes at a time.

 

[Kelpie]

Hmm...

Energy per gram is meaningless when you are carting the gas around in a big steel bottle!
You need to do a volumetric comparison.

 

[AngusMcDoon]

Not all liquid fuels are created equal! Energy density of alcohol is considerably less (40% or so) than paraffin.

All the -ols have an -OH group in them, so they are a bit burnt before you start. I'm sure the chemist will shudder at my terminology.

 

[FWB]

Annoyingly, with paraffin you end up carrying alcohol anyway for pre-heating, as I for one cannot be bothered standing holding a blowtorch for two minutes at a time.

I have no problem with using Meths to preheat my Taylors cooker. It's not wasted heat nor time since I use the preheat as part of the cooking then switch to paraffin.

 

[AngusMcDoon]

Energy per gram is meaningless when you are carting the gas around in a big steel bottle!
You need to do a volumetric comparison.

Without doing the calculations I suspect that there's not a lot in it between gas and spirit on energy per volume taking into account the container. Other liquid fuels would win as they are high energy density and don't need a hefty bottle to store them in.

 

[Otter]

Cheap purple Meths is adulterated with water and very slow. Near pure non smelly Meths like the B&Q liquid is almost as fast as gas, certainly quicker than electric.

 

[Kelpie]

All the -ols have an -OH group in them, so they are a bit burnt before you start. I'm sure the chemist will shudder at my terminology.

And is there not a proportion (5-10%) of water in commercially available alcohol as well? That won't help, although it does help reduce sooting.

Just checked a mate's blog, he used 25l (i.e 20kg) of paraffin over six months living aboard and cooking for two. At the prices I pay that is about £17.50. By my back-of-envelope calculations the equivalent in meths would be about £90, based on £12 for a 5l bottle. How much gas do people get through over that period?

 

[Kelpie]

I have no problem with using Meths to preheat my Taylors cooker. It's not wasted heat nor time since I use the preheat as part of the cooking then switch to paraffin.

Same here, just we seem to get through quite a lot of meths. Possibly because SMWBO is determined never to have a flareup on the burner and uses it like it's going out of fashion.

 

[Otter]

And is there not a proportion (5-10%) of water in commercially available alcohol as well? That won't help, although it does help reduce sooting.

Just checked a mate's blog, he used 25l (i.e 20kg) of paraffin over six months living aboard and cooking for two. At the prices I pay that is about £17.50. By my back-of-envelope calculations the equivalent in meths would be about £90, based on £12 for a 5l bottle. How much gas do people get through over that period?

We set off for our annual six week cruise with 20l of Meths which costs £65 over the internet, that lasts the whole cruise with at least five litres left. We cook for five and use it for the oven, particularly on passage when there's lots of breeze to reduce the heat in the galley and stuffing everything into an oven pot saves minding the stove and stirring pans. The burner covers need to be the real deal, we used home made ones last year and they were acting like wicks and evaporating the stuff! I totally get why people use gas, you turn a knob and the thing is on, no filling up Meths burners etc, just for us we like the safety and availability of spirit.

 

[maby]

And is there not a proportion (5-10%) of water in commercially available alcohol as well? That won't help, although it does help reduce sooting.

Just checked a mate's blog, he used 25l (i.e 20kg) of paraffin over six months living aboard and cooking for two. At the prices I pay that is about £17.50. By my back-of-envelope calculations the equivalent in meths would be about £90, based on £12 for a 5l bottle. How much gas do people get through over that period?

We spend about 50% of our time on the boat. We use the 3.5(ish) kg Calor bottles and recon we're doing ok if we get four weeks out of one. If we were full-time liveaboard, I can't imagine we would use less than eight or ten cylinders in six months - more difficult to store than 25l of paraffin.

Don't get me wrong - I certainly would not change from gas, but on the other hand, I have no intention of setting off round the world!

 

[vyv_cox]

We get about four weeks out of a 2.7 kg Camping Gaz (Greek equivalent), so around six bottles for six months aboard but eating out once or maybe twice per week. At last year's Greek prices that's about €50 - 60.