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Go Back   SailNet Community > Out There > Cruising & Liveaboard Forum > Galley Oven
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Topic Review (Newest First)
10-23-2013 08:44 AM
MSter
Re: Galley Oven

Well...both luck and timing are on my side! My new slip neighbor purchased an OI41 just a few days after I purchased mine. He is wanting to get rid of the alcohol stove and has offered to swap for my electric. This will give me an opportunity to try out the alcohol stove with no outlay of $$$!. Should this not work out for us, I can go propane. Is crazy how things work out sometimes......

Quote:
Originally Posted by Cruisingdad View Post
Might have some good news for ya...

Don's Discount in Tampa had a used propane stove the last time I was there. I bet that isn't the only one. It looked to be in good shape ad was a Princess I think (my favorite). I also bet you can find a lot of the parts you want from there and save a LOT of money. I got some things from them and it was insane price differences versus your local West Marine.

Where are you keeping your boat? We spent a lot of time in St Pete. Loved it there.

Brian

PS Definitely go propane, but do it right. If you do decide to go ahead with the camping stove, for about $15, you can get a converter to go from the little green bottles to a full sized propane bottle. You could even run an extension on it to keep it outside the boat. That is not how I would do it. Like Mark, I think do it right the first time. But we are (like Mark) live aboards so our perception on these things can be different from weekenders. I am not a fan of alcohol stoves. Too expensive and too much of a pain to get alcohol. Propane is readily available everywhere (though it can often be a walk). I have often said that cruisers covet propane more than anything because it always seems to involve a long walk or taxi ride. I cannot imagine the pain that alcohol would give!! I have never used a diesel stove, but I would research it given how we use our boat. The thought of being able to stop at any marina and get 'fuel' would be awesome... but I suspect those diesel stoves stink like the diesel heaters do. But again, I don't know.
10-22-2013 05:48 PM
outbound
Re: Galley Oven

Can't image not having a stove on a sailboat. If living on land and just doing brief cruising you can prepare meals, freeze them and then just heat them up when needed. When doing passages this becomes even more important. When living aboard for any period the smell of "something in the oven" just makes your day.
Would suggest when doing your propane get at least a three burner. More cooktop space keeps the food in the pan not on the sole even when using just one burner. With three + burners you can cook a real meal in a reasonable time.
10-22-2013 05:27 PM
Solandri
Re: Galley Oven

Quote:
Originally Posted by tdoster View Post
But going back to the cost of BTU of heat produced. If we look at efficiency, we would have to say 100% efficient cooking would be a fuel that passes 100% of it's energy to the work of cooking the food with 0% lost to transient heat. OK, that is not possible, so we look at what does it cost me to cook my eggs and bacon in the morning and what other factors can I apply to it?
I assumed any energy lost to transient heat while cooking (i.e. heating the air and your cabin instead of the food) would be the same for electric or propane. Since it scales the same for both types of stoves, it's not a factor. Either propane is 100% efficient and a gas generator is 25% efficient. Or propane is 50% efficient and a gas generator is 12.5% efficient. It's a 4:1 ratio either way.

Quote:
That changes at the dock as you have to get into some pretty high KW rates to exceed the cost of propane. Ours is currently .12 per KW hour. Plumbed natural gas is almost always cheaper, thus the strong argument for gas @ home. So, dock is less, generator is more.
That's a very good point, but I was trying to keep this in terms of a fuel efficiency standpoint to avoid bogging my post down with math. To convert it to cost efficiency, you need to multiply by the $ per BTU (or kWh). Or probably what's more accessible to most people, ($/gal) / (BTU/gal). The rough BTU/gal of various fuels are:

Diesel: 139,000 BTU/gal (1.39)
Gasoline: 124,000 BTU/gal (1.24)
Propane: 91,000 BTU/gal (0.91)
Nat Gas: ~1050 BTU/ cu ft (0.0105)

If diesel is $4/gal, gasoline $3.50/gal, Propane is $3/gal, and natural gas is $12 per 1000 cu ft, then you're paying:

Diesel: ($4/gal) / (1.39) = $2.88 per 100,000 BTU
Gasoline: ($3.5/gal) / (1.24) = $2.82 per 100,000 BTU
Propane: ($3/gal) / (0.91) = $3.30 per 100,000 BTU
Nat Gas: ($0.012/cuft) / (0.0105) = $1.14 per 100,000 BTU

Which explains why nobody is racing to build a propane-powered boat (it contains less energy per dollar than gas or diesel). Divide by the efficiency and you get:

Diesel = $2.88 / .35 = $8.22 per 100,000 BTU used for heating
Gasoline = $2.82 / .25 = $11.29 per 100,00 BTU used for heating
Propane: $3.30 / 1.00 = $3.30 per 100,000 BTU used for heating
Nat Gas: $1.09 / 1.00 = $1.09 per 100,000 BTU used for heating

Electricity from shore power can be generated from many sources. Hydro in particular is dirt cheap to produce (2-3 cents/kWh). Even the coal plants the power company operates are 45%-55% efficient, with their gas furnaces exceeding 60%. So shore power electricity is a lot cheaper per kWh than from running your own generator. This is the same thing that makes the economics of electric cars work. Electricity is actually a terrible way to power a car (fuel => combustion => generator => electricity => power line => car battery => motor => move car, compared to fuel => combustion => transmission => move car). But the power company's generators are a lot more efficient than your car engine, and coal/nat gas is a lot cheaper than gasoline. And as a result the cost of the electricity needed to drive an electric car 1 mile ends up being about 1/3rd what it would cost in gasoline.

If we convert a typical 11 cents/kWh to the same units as above (29.3 kWh per 100,000 BTU), we get:

($0.11/kWh) * (29.3) = $3.22 per 100,000 BTU used for heating

So shore power does slightly edge out propane for heating. Normalizing these against propane, you get:

Diesel: 2.49x
Gasoline: 3.42x
Propane: 1.00x
Nat Gas: 0.35x
Shore power: 0.98x

Substitute your own local prices for the different fuels into the math above to find out how they stack up locally. The math is just straight multiplication and division so goes into a spreadsheet easily. (Bear in mind the efficiency figures for diesel and gasoline are rough averages, so diesel is probably more like 2-3x more expensive than propane, and gasoline 3-4x more expensive.)
10-22-2013 03:38 PM
tdoster
Re: Galley Oven

Quote:
Originally Posted by Solandri View Post
The problem with electric heat is that a gasoline generator is only about 30% efficient, a diesel generator about 40% efficient, and there are additional conversion losses if you use an inverter or a battery. That is, of all the energy in the fuel, only about 25%-35% of it gets converted to usable electricity. The other 65%-75% of the energy in the fuel is discarded as waste heat into the sea and air, even though the whole point of this exercise is to heat up your stove or oven.

With a propane, alcohol, or natural gas stove, 100% of the energy in the fuel is converted to heat for cooking food in the stove/oven. (Some of it will end up heating the cabin instead of the food, but the same is true for electric, unless you go with induction heating.)

It is extremely difficult if not impossible to overcome this 3:1 to 4:1 efficiency advantage of propane from a financial standpoint. About the only way an electric stove/oven makes sense if your electricity is generated from solar or wind (thus avoiding the efficiency losses of the generator), or from very cheap shore power (usually hydro in the Pacific Northwest). Or if you're willing to pay extra for the simplicity of only having to haul around one type of fuel.
Most of it depends on how you use your boat. But for us, mainly coastal and Caribbean and a motorsailor, this setup works well. If doing more offshore work it would be a different ball game.

I won't argue with the efficiency of Propane or CNG as it relates to cost per BTU compared to using a generator, but will argue with your efficiency logic as it is a segmented argument and should be linear as well as the costs @ the dock.

Efficiency in internal combustion engines as a term is based upon the amount of work achieved from a measurement of fuel. What is left over is lost to heat. So, when measuring efficiency in an internal combustion engine, we are looking at the fuel burned, how much work is produced at the shaft and how much energy is lost to heat. That would be simple MPG in a car as we just want to measure how far we got off that tank of gas.

Cost per BTU of heat is what I think you were going for, but using a percentage of 100% I don't feel is correct.

Nut is, what does it cost me to cook my dinner? If we look at the overall picture, we also have to look at the efficiency of the fuel used and give a percentage of how much of the work was applied to just cooking. As well as the other factors that we can personally assign a dollar amount to. Tongue and cheek, I personally am 50% less efficient compared to 20 years ago, thus I can put a personal value to the fact of lugging a propane bottle around trying to find someone to fill it.

But going back to the cost of BTU of heat produced. If we look at efficiency, we would have to say 100% efficient cooking would be a fuel that passes 100% of it's energy to the work of cooking the food with 0% lost to transient heat. OK, that is not possible, so we look at what does it cost me to cook my eggs and bacon in the morning and what other factors can I apply to it?

The tank that came in my boat was a 10lb tank, which is roughly 2 gallons of propane, which equates into about 200K BTU's, very simplified math. If I just use the small stove burner of 7K BTU's, I would get around 28 hours of total cooking from 2 gallons of propane (if just using the little burner on the stove). Not going to go into alcohol or using the oven - but my wife likes the way electric cooks over gas. If I were to just use the generator to cook, that would equate into 7 gallons of fuel on my 4KW Diesel @ 1/4 gallon an hour. So, apples to apples, there is no contest. Your argument wins!

That changes at the dock as you have to get into some pretty high KW rates to exceed the cost of propane. Ours is currently .12 per KW hour. Plumbed natural gas is almost always cheaper, thus the strong argument for gas @ home. So, dock is less, generator is more.

OK, so I have to go through some other factors. The generator provides much more for the work it is producing at the 1/4 gallon hour rate, from battery charging, making water, heating water, cooling, heating or drying the boat, etc. At the dock, costs are based upon KW hour, off the umbilical, based upon output and efficiency of the generator.

I think the long-winded point is there is no right or wrong answer to the question. The cost at the dock is far less for electric all things considered from experience. Each one has advantages and drawbacks and each one is also based upon personal choice and economics and how and where you plan to sail. The only natural drawback is you really need 50 amp service. If we run at 30 amps, it is really easy to push it so you have to add amps in your head and turn things on and off short of throwing breakers. And my favorite argument as a sailor. Cooking and powering the boat are not a single failure point with gas.
10-21-2013 03:37 PM
Solandri
Re: Galley Oven

Quote:
Originally Posted by tdoster View Post
Running the genset to cook also charges the batteries and cool and dry things off a bit with the a/c, so we try and take advantage of that time as much as possible, or the main engine and 100 amp alt is enough to run the hotplate and microwave with the 2000 watt inverter.
The problem with electric heat is that a gasoline generator is only about 30% efficient, a diesel generator about 40% efficient, and there are additional conversion losses if you use an inverter or a battery. That is, of all the energy in the fuel, only about 25%-35% of it gets converted to usable electricity. The other 65%-75% of the energy in the fuel is discarded as waste heat into the sea and air, even though the whole point of this exercise is to heat up your stove or oven.

With a propane, alcohol, or natural gas stove, 100% of the energy in the fuel is converted to heat for cooking food in the stove/oven. (Some of it will end up heating the cabin instead of the food, but the same is true for electric, unless you go with induction heating.)

It is extremely difficult if not impossible to overcome this 3:1 to 4:1 efficiency advantage of propane from a financial standpoint. About the only way an electric stove/oven makes sense if your electricity is generated from solar or wind (thus avoiding the efficiency losses of the generator), or from very cheap shore power (usually hydro in the Pacific Northwest). Or if you're willing to pay extra for the simplicity of only having to haul around one type of fuel.
Quote:
I also like to heat coffee and soup up prior to a passage and keep it in thermoses to stay warm, thus not having to heat up water as often. After heating it up, store it in a Pizza Delivery bag.
A thermos is best, but if you use a lot of hot water and are regularly on shore power you can get an Asian style hot water dispenser like the Zojirushi CV-DSC40. That particular model is one of the more expensive ones, but has a vacuum chamber making it more efficient. I have one and it draws about 17 Watts to maintain 4 liters at 195 F (about 1300 Watts when heating it). They're designed so you can heat water, unplug it, and take it with you out to a picnic. So you don't necessarily have to leave it plugged if you're just out for a day cruise. The cheaper models use foam and plastic insulation, and draw about twice the wattage to maintain the water temp.
10-21-2013 02:21 PM
tdoster
Re: Galley Oven

Quote:
Originally Posted by Minnewaska View Post
Not always the case with marine policies. They can often deny coverage for improper installation or even improper maintenance. These are nasty exclusions to be well understood.
Boat sinks from a seacock or hose that broke. Any reputable insurance company will pay it regardless (to limits). Smarter companies are using the survey to request those items are repaired prior to coverage or deny coverage all together, on larger boats. They may fight you on a claim, but when pressed will pay out.

They will ALWAYS pay liability as far as the limits no matter what. They can't win a liability case against an innocent third-party regardless of what exclusions they sold you and they are required to defend you no matter what.
10-21-2013 01:17 PM
Cruisingdad
Re: Galley Oven

Quote:
Originally Posted by MSter View Post
While I did contemplate that one, I found one just down the coast near Ft Myers. What a smooooth sail home today!
Might have some good news for ya...

Don's Discount in Tampa had a used propane stove the last time I was there. I bet that isn't the only one. It looked to be in good shape ad was a Princess I think (my favorite). I also bet you can find a lot of the parts you want from there and save a LOT of money. I got some things from them and it was insane price differences versus your local West Marine.

Where are you keeping your boat? We spent a lot of time in St Pete. Loved it there.

Brian

PS Definitely go propane, but do it right. If you do decide to go ahead with the camping stove, for about $15, you can get a converter to go from the little green bottles to a full sized propane bottle. You could even run an extension on it to keep it outside the boat. That is not how I would do it. Like Mark, I think do it right the first time. But we are (like Mark) live aboards so our perception on these things can be different from weekenders. I am not a fan of alcohol stoves. Too expensive and too much of a pain to get alcohol. Propane is readily available everywhere (though it can often be a walk). I have often said that cruisers covet propane more than anything because it always seems to involve a long walk or taxi ride. I cannot imagine the pain that alcohol would give!! I have never used a diesel stove, but I would research it given how we use our boat. The thought of being able to stop at any marina and get 'fuel' would be awesome... but I suspect those diesel stoves stink like the diesel heaters do. But again, I don't know.
10-21-2013 12:30 PM
Minnewaska
Re: Galley Oven

Quote:
Originally Posted by tdoster View Post
Insurance will cover up to your limits - period. Regardless of stupidity, .....
Not always the case with marine policies. They can often deny coverage for improper installation or even improper maintenance. These are nasty exclusions to be well understood.
10-21-2013 11:24 AM
tdoster
Re: Galley Oven

Quote:
Originally Posted by seaner97 View Post
Second the insurance issue. If you're unlucky enough to blow you(and the boats around you) up but survive, I doubt your insurance will cover you (or the Hinkley you damaged ).
Insurance will cover up to your limits - period. Regardless of stupidity, which only increases rates for the rest of us.


My take on the debate is I am one who actually likes electric, but don't use the oven a whole lot (especially at sea) and still BBQ on the grill @ anchor. Underway, it seems we do an awful lot of getting from point A to point B and have to motor as ideal sailing conditions are not the norm at least for us. My theory is it is a one-stop shop for diesel when cruising and lugging a propane cylinder around with laundry and provisions takes away more of the fun - not to mention finding a filler. Running the genset to cook also charges the batteries and cool and dry things off a bit with the a/c, so we try and take advantage of that time as much as possible, or the main engine and 100 amp alt is enough to run the hotplate and microwave with the 2000 watt inverter. I also like to heat coffee and soup up prior to a passage and keep it in thermoses to stay warm, thus not having to heat up water as often. After heating it up, store it in a Pizza Delivery bag.
10-06-2013 11:35 PM
MSter
Re: Galley Oven

Quote:
Originally Posted by miatapaul View Post
So did you buy Dream Weaver? Looks nice.
While I did contemplate that one, I found one just down the coast near Ft Myers. What a smooooth sail home today!
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