Induction vs Gas Cooking

[Dockhead]

Originally Posted by Seaworthy Lass

. . . Hmmmmm, you may have me convinced. I now need to beg for a little room on the long bench top of the adjacent technical workshop. That is where the architect suggested installing a microwave (much to Noelex’s dismay ) when I was debating where to leave room for one in the galley.. .

Can you build it in somewhere? They do take up a lot of counter space.


Or maybe you could have a combined micro/convection in place of your gas oven?


What concerns washing up -- some people are going to howl, but I think a dishwasher makes eminent good sense and I can't believe they are so rare. They save a huge amount of water and guaranty hygenic washing.

[Seaworthy Lass]

Originally Posted by Dockhead

Can you build it in somewhere? They do take up a lot of counter space.

Or maybe you could have a combined micro/convection in place of your gas oven?

Now that it is installed I wouldn’t get rid of the gas, particularly at this early stage. I think it will be needed on long passages if conditions are cloudy. Also needed if it is raining for days on end in the tropics where I wouldn’t want the Refleks on, but where our solar array wasn’t providing enough power to cook electrically. The redundancy is also good to have.

Realistically, once the novelty of baking in a frypan has worn off, I may start using the oven occasionally for baking a few favourite dishes such as lasagne (vegetarian) again. Doing this occasionally, I think the three bottles of gas that we currently have on board will last a decade or two .

SWL

[BlackHeron]

Originally Posted by Auspicious

I like your attitude.

Do you remember where you were last weekend? Sat/Sun/Mon I moved a boat from New Bern NC to Solomons MD - 2-1/2 days on the ICW to Norfolk and half a day on the Bay. I was below a lot for nav/weather/cooking/mucking about with crew on watch. I certainly would have noticed a Rasmus if we passed while I was on deck. Boat is a Freedom 40 named Caramba (being renamed Serenity).

I'm mostly an offshore guy but this trip the ICW made more sense. 90 mile days are really in reach, but that isn't cruising is it?

After you passed through the Lady's Island Bridge in Beaufort SC there is little Creek to starboard. You have to turn and follow the bridge closely to avoid the shoal. We are anchored right up that creek a half mile up from the bridge and still in sight of it. We run AIS 24/7 too. I like to watch the traffic going by on the ICW. I've seen quite a few folks from our boat card collection go by in the last month. We have been here the whole time since Coronavirus isolation became a thing as my wife is pretty high risk. Staying on the boat except to buy groceries like fresh fruits and veg.

As for whomever asked if I have been on watch 24/7, this is a very protected anchorage with very little water disturbance most of the time and it is a fairly narrow creek. To pass through a boat has to come within a boat length of the boats anchored here. Not many cruising boats get by without causing us to bob around a little, even if they are only going 1 knot idling. Plus it is pretty quiet. I can hear the folks on SUPs and kayaks paddling by, and anyrhing bigger motoring over the birds chirping.

My wife calls me Mrs Kravitz. I pop my head out and scope out every passing boat or peek out a port. I like to know what is going on around me in the neighborhood. PTSD I suppose. I catch a look at probably 95% of the larger boats and a good percentage of the locals on center consoles. Not much else to do here other than read and do boat work.

We plan on jumping up to the Chesapeake in the next couple of weeks. Safer from hurricanes and hopefully not quite as hot.

[Auspicious]

Originally Posted by Seaworthy Lass

All 148 posts again? Can I pick another penance? .

No. You can’t start in the middle. *grin* I will continue to point you upthread.

Originally Posted by Seaworthy Lass

As well as “what would you do with a raw chook” if your power source failed and “funny shaped bread is second rate”, the main thrust of your arguments has been the safety issues when using electricity.

The two main arguments induction advocates make are safety and ancillary heat.

Originally Posted by Seaworthy Lass

I think the failure mode most people are most concerned with when using gas is an unexpected big bang, which would do a bit more than just make you spill your coffee. We fitted gas taking great precautions, but it would be nice to eliminate this risk completely.

I understand the concern. It is not well founded. Insurance industry statistics point to electrical sources as the overwhelming cause of fire. The article I recalled upthread is https://www.boatus.com/seaworthy/mag...boat-fires.asp . As it happens, I am acquainted with the author who is currently Technical Director at BoatUS. In addition to correspondence I very occasionally dine with Beth and Evans. We’ve talked about this very issue and how the numbers might differ if you don’t include trailer boats. It doesn’t really change anything.

The best thing one might do is not plug into shore power. However high current DC applications go up with cruising boats. Current statistics are always aft looking so don’t reflect increased AC usage on board as more and bigger inverters enter the fleet. Induction is not well reflected in statistics and cannot possibly make things better.

I refer you again to the discussion of failure modes and effects upthread.

Digressing, don’t get me started on the evils of ANSI/SAE J563 connectors (“cigarette lighter” plugs) as relevant to fires on board.

Originally Posted by Seaworthy Lass

There are insufficient users of induction for any reasonable comparisons to be made comparing the safety of gas vs electric cooking, but I would think that if you already had a boat set up to handle high power demands (necessary if using electricity to cook with exclusively all year around) then plugging in an induction hotplate poses only a minuscule additional risk.

Again not true. Engineering provides for breaking systems down (systems, segments, elements, subsystems) for purposes of analysis. We know where the failure points are (see FMEA). As someone else pointed out, the nature of the load doesn’t affect distribution – only magnitude and time domain.

Connectors and connections are the biggest issue. I don’t know your boat or what convenience outlet standard you follow. It doesn’t matter. None of them are great. Fixed connections are better but still not perfect. See discussion upthread. I recall the biggest problem is mixed materials. Tinned copper with aluminum end fittings and fasteners of a multitude of materials often including bronze and steel. Different coefficients of expansion lead to loosening under thermal cycling (I²R from loads switching on and off). How often do you run around the boat tightening connections? How often do you really look at the plugs on power leads when you plug them in?

Originally Posted by Seaworthy Lass

To minimise this minuscule risk you could select a reputable brand, replace it frequently (it is cheap enough to even do this six monthly if you were paranoid), unplug it when not in use ......

Mostly not relevant. See upthread. Glass tops. Electronics that can’t sustain water intrusion. Electronics subject to corrosion (especially at internal connectors) and not conformally coated.

The risk is NOT minimal.

Originally Posted by Seaworthy Lass

In my view this is far, far safer than using gas, both from the explosion and naked flame perspectives.

On the facts, not opinion, your view is incorrect.

Originally Posted by Seaworthy Lass

The 12 kg relates to the weight of the gas, the tanks are additional.
The total weight of a full 12 kg gas tank can be around double this, depending on the material used.

I know. A Jerry jug of water including the container is about 20 kg, the same as a full 12 kg LPG tank.

Originally Posted by Seaworthy Lass

Now here I seriously beg to differ, simply as I have experienced the direct contrast of wintering in Scotland twice, once using gas for almost all the cooking and once no gas at all when the hotplate of the Refleks heater was used

Then I respectfully suggest more attention to ventilation than you have, with attention to cold, dry make-up air. I used gas aboard in Sweden in late winter and three winters at dock in the Barents. I refer you to the lay publication I listed upthread and to http://scholar.google.com for HVAC-R discussions in professional journals.

We are not plowing new ground here, including on small boats like ours. Consider fishing fleets in Alaska, Nova Scotia, North Sea, Skagerrak, Baltic, …. Also reread discussion on condensation above.

Originally Posted by Dockhead

That sounds reasonable. Except -- you forget the stream of hot combustion products.

All carbon based fuels produce water by combustion. LPG in a cooker. Diesel in Seaworthy Lass’ Reflex heater. Water production is proportional to the hydrogen-to-carbon ratio in the fuel. Propane throws off 25% more water than diesel. I don’t consider that “HUGE.” Significant certainly but easily managed with proper ventilation. It has been in my experience and reflected in the literature. If Seaworthy Lass found the difference HUGE then there was some other factor, likely better ventilation of the Reflex combustion chamber than of the galley.

Propane does have slightly more heat content than diesel. The efficiency gain of cooking over LPG as you note is due to fewer state conversion and inefficiencies of storage as you imply.

Originally Posted by Dockhead

]The illustrative case is simmering. You simmer with resistive heat, you are only using a tiny amount of power in the food, but there is a stream of hot air rising up around the pan. I guess the lower and lower the heat, the smaller proportion goes into the food. With induction, you are only using just that amount of power which goes into the food (less a little radiated from the pan as you point out, but this is a little).

I agree with respect to resistive heat. When you lower a gas flame the diameter of flame reduces. Add choosing the proper size burner and there is reduced loss.

Which leads to your comments about four burner cookers on boats. The biggest problems are balance and space. While I desperately miss my old six burner commercial cooktop my little two burner is quite convenient. We’re talking preferences now, not science. I like being able to squeeze a 12” skillet and a 2 qt pot on, or bridging both burners with my 14” skillet. A cast iron griddle fits over both.

The alternative is juggling too-small pots and pans to “fit” and having a kettle full of water to act as a counter balance. Bah! Try feeding four people for two weeks (I’m sure you have) when your “big” pan is 8” diameter. Bah! Again.

Originally Posted by Dockhead

I've not had this issue. I inherited a set of expensive Cristel cookware from the PO of my boat; it works fine. I bought a couple of specific induction pans to supplement. It all works great and no buzz. YMMV. But I guess any pan which was designed for induction, and most these days are, will not have problems.

It depends on what you spend. It is my understanding that the buzz comes from poor bonding of layers of material in the construction of the cookware. “Designed for induction” means it gets hot on an induction hob, that’s all.

Note 800W is 2700 BTU/hr, well within the range of a mid-range boat cooker.

Originally Posted by Dockhead

I would like to understand how that works. Why is this a "subsidiary risk"? Risk from a gas system stands alone. If you have gas -- you have that quantum of risk.

Context. I’m looking at total risk, say risk of the boat burning. Since the risk of fire/explosion from LPG is lower than the risk of fire from electricity it is the subsidiary risk. Again, I don’t have the equations in my head. I remember how they work. I can look them up if you like. You can talk to an actuary in the back office of any insurance company and get a proper explanation.

Originally Posted by Dockhead

I believe it works just like driving or not driving. I go out in my car today -- I have x risk of having a road accident. I stay home today -- I have 0 risk of having a road accident. Difference is -x.

If you go driving you could be hurt in a road accident, hurt could range for bruises to death. If you stay home you could slip and fall in the bath and be hurt ranging from bruises to death (different probabilities). Your house could catch fire. Risk is risk.

Originally Posted by Dockhead

By the way, you kept talking about fire. The risk with gas is not fire, it's explosion.

I suggest the difference is not great. Yes, there is a technical difference between what a fire is and what an explosion is. Boat fires are usually catastrophic, particularly when they start in concealed spaces (e.g. electrical). Have you ever watched a boat burn? It happens very fast.

I fully agree with the fact that LPG is heavier than air. That’s where most of the risk comes from. Thus the addition of odor agents in commercial LPG so you can smell leaks. Thus the external locker drained overboard. Thus the gas alarm. Thus the advisability of using the Mark I nose. You sniff your boat every time you go below right? Diesel, oil, gas, petrol, ozone, the unique smell of a kettle left on the heat to boil dry, ….

Anecdotes can be alarming. The explosion of the Space Shuttle Challenger could put one off space travel. It certainly reduced the enthusiasm of the US Congress for the shuttle program. That doesn’t mean they are good tools for decision making. While agree with “lies, damn lies, and statistics” they are darn handy things for getting emotional reactions out of a decision tree.

Originally Posted by Seaworthy Lass

This is heated simply in a covered frypan or pot on the Refleks or induction hotplate or gas burner. I make soups and stews in batches and seal this while piping hot in glass jars (a short term form of “preservation”) and refrigerate the jars until needed. The flavour of these dishes tends to improve even further with time. I find this reheated food is actually even better than when freshly made so I use this technique a lot.

More solid things, lasagna for example, can be reheated in a pan with a bit of water surrounding and a lid. The steam reheats the food before the bottom burns.

[BlackHeron]

Originally Posted by Dsanduril

100A coming out of the battery is 100A coming out of the battery - the battery doesn’t care about the distance to the load.

Ohm's law and Joule's Law don't work that way.

Resistance over longer runs causes a LOT of voltage drop with high amp loads since 12 volt systems require fairly large currents to carry the power to loads that require it. The higher the current the more voltage drop as well as the longer the run the more resistance and again the more voltage drop..


Voltage drop produces or coincides with higher I²R losses (heat) at higher currents. The wire basically becomes a heating element, and it also requires even more current to flow through the circuit to compensate and balance the ohms law equation. More current produces yet more voltage drop and even more more heat in a downward death spiral if things get bad enough. This is one of the reasons the ABYC requires insulation on wires to be rated for 105C. That's more than hot enough to boil water. 12v is a poor voltage for high power loads and over any distance of wire more than a few feet.

I am (or was) a commercial electrician so I'm trying to phrase this in a way that a layman might understand it. Maybe an actual EE could explain it better than a working slob with dirt under his fingernails.

The problem I see with this whole debate is that a lot of people who don't even understand how electricity works are arguing why an electric stove (induction or conventional resistive elements) is better than gas.

[Auspicious]

Originally Posted by BlackHeron

I am (or was) a commercial electrician so I'm trying to phrase this in a way that a layman might understand it. Maybe an actual EE could explain it better than a working slob with dirt under his fingernails.

I'm not a EE. I'm a naval architect and marine engineer. We had a lot of EE in school and I use it regularly to this day. I have great respect for working slobs with dirt under their nails. I think your explanation was spot on.

[mako]

Originally Posted by Dockhead

What concerns washing up -- some people are going to howl, but I think a dishwasher makes eminent good sense and I can't believe they are so rare. They save a huge amount of water and guaranty hygenic washing.

I've never been a fan of dishwashers, not even at home. The need to pre-rinse or scrub them (especially crusted waste, or melted cheese) negates the advantage of a DW, especially when you're already 90% clean by the time you load up.

However, I've been rethinking this lately, thinking about the next boat. A saltwater wash in the galley would allow as much scrubbing as desired. Then the DW can provide the final rinse and save a lot of potable water. Plus make the wife happy!

[slug]

Originally Posted by Auspicious

No. You can’t start in the middle. *grin* I will continue to point you upthread.


The two main arguments induction advocates make are safety and ancillary heat.


I understand the concern. It is not well founded. Insurance industry statistics point to electrical sources as the overwhelming cause of fire. The article I recalled upthread is https://www.boatus.com/seaworthy/mag...boat-fires.asp . As it happens, I am acquainted with the author who is currently Technical Director at BoatUS. In addition to correspondence I very occasionally dine with Beth and Evans. We’ve talked about this very issue and how the numbers might differ if you don’t include trailer boats. It doesn’t really change anything.

The best thing one might do is not plug into shore power. However high current DC applications go up with cruising boats. Current statistics are always aft looking so don’t reflect increased AC usage on board as more and bigger inverters enter the fleet. Induction is not well reflected in statistics and cannot possibly make things better.

I refer you again to the discussion of failure modes and effects upthread.

Digressing, don’t get me started on the evils of ANSI/SAE J563 connectors (“cigarette lighter” plugs) as relevant to fires on board.


Again not true. Engineering provides for breaking systems down (systems, segments, elements, subsystems) for purposes of analysis. We know where the failure points are (see FMEA). As someone else pointed out, the nature of the load doesn’t affect distribution – only magnitude and time domain.

Connectors and connections are the biggest issue. I don’t know your boat or what convenience outlet standard you follow. It doesn’t matter. None of them are great. Fixed connections are better but still not perfect. See discussion upthread. I recall the biggest problem is mixed materials. Tinned copper with aluminum end fittings and fasteners of a multitude of materials often including bronze and steel. Different coefficients of expansion lead to loosening under thermal cycling (I²R from loads switching on and off). How often do you run around the boat tightening connections? How often do you really look at the plugs on power leads when you plug them in?


Mostly not relevant. See upthread. Glass tops. Electronics that can’t sustain water intrusion. Electronics subject to corrosion (especially at internal connectors) and not conformally coated.

The risk is NOT minimal.


On the facts, not opinion, your view is incorrect.


I know. A Jerry jug of water including the container is about 20 kg, the same as a full 12 kg LPG tank.


Then I respectfully suggest more attention to ventilation than you have, with attention to cold, dry make-up air. I used gas aboard in Sweden in late winter and three winters at dock in the Barents. I refer you to the lay publication I listed upthread and to http://scholar.google.com for HVAC-R discussions in professional journals.

We are not plowing new ground here, including on small boats like ours. Consider fishing fleets in Alaska, Nova Scotia, North Sea, Skagerrak, Baltic, …. Also reread discussion on condensation above.


All carbon based fuels produce water by combustion. LPG in a cooker. Diesel in Seaworthy Lass’ Reflex heater. Water production is proportional to the hydrogen-to-carbon ratio in the fuel. Propane throws off 25% more water than diesel. I don’t consider that “HUGE.” Significant certainly but easily managed with proper ventilation. It has been in my experience and reflected in the literature. If Seaworthy Lass found the difference HUGE then there was some other factor, likely better ventilation of the Reflex combustion chamber than of the galley.

Propane does have slightly more heat content than diesel. The efficiency gain of cooking over LPG as you note is due to fewer state conversion and inefficiencies of storage as you imply.


I agree with respect to resistive heat. When you lower a gas flame the diameter of flame reduces. Add choosing the proper size burner and there is reduced loss.

Which leads to your comments about four burner cookers on boats. The biggest problems are balance and space. While I desperately miss my old six burner commercial cooktop my little two burner is quite convenient. We’re talking preferences now, not science. I like being able to squeeze a 12” skillet and a 2 qt pot on, or bridging both burners with my 14” skillet. A cast iron griddle fits over both.

The alternative is juggling too-small pots and pans to “fit” and having a kettle full of water to act as a counter balance. Bah! Try feeding four people for two weeks (I’m sure you have) when your “big” pan is 8” diameter. Bah! Again.



It depends on what you spend. It is my understanding that the buzz comes from poor bonding of layers of material in the construction of the cookware. “Designed for induction” means it gets hot on an induction hob, that’s all.

Note 800W is 2700 BTU/hr, well within the range of a mid-range boat cooker.


Context. I’m looking at total risk, say risk of the boat burning. Since the risk of fire/explosion from LPG is lower than the risk of fire from electricity it is the subsidiary risk. Again, I don’t have the equations in my head. I remember how they work. I can look them up if you like. You can talk to an actuary in the back office of any insurance company and get a proper explanation.


If you go driving you could be hurt in a road accident, hurt could range for bruises to death. If you stay home you could slip and fall in the bath and be hurt ranging from bruises to death (different probabilities). Your house could catch fire. Risk is risk.



I suggest the difference is not great. Yes, there is a technical difference between what a fire is and what an explosion is. Boat fires are usually catastrophic, particularly when they start in concealed spaces (e.g. electrical). Have you ever watched a boat burn? It happens very fast.

I fully agree with the fact that LPG is heavier than air. That’s where most of the risk comes from. Thus the addition of odor agents in commercial LPG so you can smell leaks. Thus the external locker drained overboard. Thus the gas alarm. Thus the advisability of using the Mark I nose. You sniff your boat every time you go below right? Diesel, oil, gas, petrol, ozone, the unique smell of a kettle left on the heat to boil dry, ….

Anecdotes can be alarming. The explosion of the Space Shuttle Challenger could put one off space travel. It certainly reduced the enthusiasm of the US Congress for the shuttle program. That doesn’t mean they are good tools for decision making. While agree with “lies, damn lies, and statistics” they are darn handy things for getting emotional reactions out of a decision tree.


More solid things, lasagna for example, can be reheated in a pan with a bit of water surrounding and a lid. The steam reheats the food before the bottom burns.

Your safety argument is poorly considered

All modern cruisers have large battery banks , powerful chargers , powerful inverters , powerful electric consumers and complexity

You could consider these modern , complex , yacht electrical systems inherently dangerous

Using your thought process , adding one more dangerous system of stored gas , open flame and carbon monoxide .... makes a boat with an already complex electrical component system safer

You are wrong

As to the Original poster ... go for induction, it’s fantastic

When the next boat show appears do a survey of induction installations on modern yachts to get some ideas on gimbling and sea rails for pots and pans

Builders in the Netherlands have very well designed cooker installations

[CatNewBee]

Originally Posted by Dockhead

Great, real life experience


Do you have numbers on daily AH used for cooking?

Its hard to measure, because it is always a mix of things we use at the same time, when you cook, you also wash some stuff with hot water, so the boiler gets also some power, up to 100A are comming in from solar, so not clear how many Ah actually comming from the battery and going to the induction hob.

We have some raw values about our consumption, 30% are direct solar use, 70% go into the battery and are used from the battery daily. We produce and use between 8 and 10kWh per day, but this includes hot water, refrigeration, cooking and all other things.

[BigNut]

Regarding fitting a microwave, we have recently installed:

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

and it fits the bill for a very compact microwave. It will hold a fullsize plate, and will fit into a corner. Only 750w, but that is not an issue for us. I love popcorn, and this easily beats an airpopper when combined with one of those silicone popcorn makers.

[CatNewBee]

We are at the dock due to Roona, so we have used some shore power for A/C and the dehumidifyer during this time, also the hot water boiler was always on, some days with heavy washing machine usage and the like, this are our statistics, most of the time there was solar only consumption.

[Pete7]

Originally Posted by Auspicious

I could use some numbers here for how in high latitudes you can run an induction hob for hours on end off solar at low angles for only a few hours per day. How much solar do you have?

Not numbers for cooking, but by chance I took a look at the Victron app after adding the winter lines back on today, its blowing F7 through the harbour and a bit bouncy on a small yacht.

So the 300w solar panel woke up the Victron MPPT at 5am this morning and went into bulk. Bulk lasted 2 hours until almost exactly 7am. Then followed 1 hour of absorption. At 8am the whole lot dropped into float. Okay the batteries were full, but even if discharged the absorption could have gone on for many hours during the day. Sunset isn't until 9pm tonight. Living at 50'N has some real advantages and a disadvantage. Oodles of daylight during the summer which conveniently coincides with the sailing season means lots of solar. Cooler air temperatures particularly if you have good ventilation to the back of the panels helps keep the temperature down. Disadvantage is you really need to hibernate for December and January.

SWL and Noelex have 3 times the solar power, no idea what they do with it, guess they may as well make bread each day oh and they are another 7 deg further north. They won't even need a torch at night and probably need to leave the anchor ball up so everyone can see it rather than use a light.

Originally Posted by Auspicious

Absolutely. Copper has twice the thermal conductivity of aluminum, which in turn is much better than cast iron or mild steels. This is why Revere Ware was so popular at one time. The cost of copper has greatly increased and aluminum and clad aluminum is the current best value for money, especially in commercial cookery. If you want something really great for heat distribution you can find copper cookware with stainless steel or even silver cladding inside. If you can afford that you can hire a boat boy to keep it polished. *grin*

We cook stainless steel pans at home. The stainless pans on the boat might be copper clad stainless, need to check that. If not then its a summer of searching out the charity shops in the more affluent towns.

Pete

[Dockhead]

Originally Posted by Auspicious

. . . The two main arguments induction advocates make are safety and ancillary heat.

3. absence of combustion products in the cabin, 4. higher quality of the cooking experience; 5. reduction of the number of systems to maintain; 6. reduction of the number of different fuels to supply. Compared to gas, efficiency is not an advantage of induction.

Originally Posted by Auspicious

. . I understand the concern. It is not well founded. Insurance industry statistics point to electrical sources as the overwhelming cause of fire. . . .

That fact is not relevant to the relative safety of gas vs electric cooking. By itself, that fact shows nothing. The average gas explosion is probably 100x more destructive and more likely to cause injury or death, than the average electrical fire. The 100x is a guess, but we have to know this coefficient in order for the relative frequency of fires or explosions, to have any meaning.


But again, comparing gas risk vs. electrical risk is also a total irrelevancy. It's comparing the total fire/explosion risk of a boat which uses induction vs. the total fire/explosion risk of a boat which uses gas. This is an entirely different question than gas vs electricity.



You have not yet shown why eliminating the risk of gas explosions without increasing the risk of electrical fires does not reduce the risk overall.



I would love to be shown why I'm wrong about this. In disagreements with smart people, I always come out the winner when some belief of mine is demonstrated to be wrong, so that my knowledge is improved. I am still hoping for a win here, but as far as I can see I'm still losing

Originally Posted by Auspicious

. . . Induction is not well reflected in statistics and cannot possibly make things better.

I can see how if adding induction cooking to a boat without other high current AC loads might materially increase risk of electrical fires. This would not be the case on boats where adding inductive cooking does not materially increase the total amount of the load.


Furthermore, the risk of electrical fire will not increase as a linear function of the power used. If you have a fault which is capable of causing a fire, the risk will appear early as you increase loads and won't increase much later.


Lastly, I'm not convinced that even adding an AC power system to boat which didn't even have one, in order to eliminate a gas system, would not reduce the risk.



We simply don't have any data which could indicate whether that would be the case of not, or at least none of have been presented here.


I gave a list of gas explosions in the UK over 6 years on cruising-sized boats, possibly not a complete list. The list of cruising-sized boats destroyed, with human injuries, by electrical fires is not an order of magnitude more than this, in fact, I think the list is shorter. In fact, I don't recall a single electrical fire on a cruising boat in the UK with human injury, much less death. Maybe (probably) the wiring is better quality here, and of course 230v is much safer from point of view of fire, and POSSIBLY this makes the whole equation different here than in the U.S.



Risk vs. utility of gas systems, which serve only one function, has got to be vastly less, orders of magnitude less, than the risk vs. utility of electrical systems which serve dozens of functions.



I just do not see how eliminating gas without materially increasing electrical risk could not be a significant, not just material, but significant improvement in safety.


Now, show me why I'm wrong, and I'll be extremely grateful!!

Originally Posted by Auspicious

. . .Again not true. Engineering provides for breaking systems down (systems, segments, elements, subsystems) for purposes of analysis. We know where the failure points are (see FMEA). As someone else pointed out, the nature of the load doesn’t affect distribution – only magnitude and time domain.

OK, so if adding inductive cooking does not materially increase magnitude or time domain or magnitude x time domain, or whatever, of the electrical loads, then risk doesn't increase, right? That accords with common sense.


I'm sure however that it's not a simple function like that. The risk of having an electrical fire must be very low with small loads, and suddenly spikes up at certain loads, and probably does not increase much once you've reached a certain threshold. I guess using a 2kW heater (or two of them!) 24/7 dwarfs any possible other electrical fire causing load, making any other electrical fire causing load a rounding error.

Originally Posted by Auspicious

Connectors and connections are the biggest issue. I don’t know your boat or what convenience outlet standard you follow. It doesn’t matter. None of them are great.

I think the different types of connectors vary a lot in quality. The cheap U.S. NEMA 1-15 ones are shocking. Especially considering that for a given wattage this connector has to carry double the current. The continental Shuko ones are better -- probably what SWL has, right? But I really like the expensive and bulky UK BS1363 individually fused ones. I used to think they were massive overkill; I've totally come around now. The BS1363 plug compared to other plugs is like the SmartPlug shore power connector compared to others, and for similar reasons (huge contact area, etc etc). Just don't buy the less expensive BS1363's, make sure the wiring is good and well connected, and you can put a couple of kilowatts through these with confidence.


https://www.fastcompany.com/3032807/...ckets-on-earth



I do get that from a U.S. perspective dealing with a 110v system and these crappy connectors, using high load AC gear seems much scarier, than it does to us.


When I lived in the States, I had some kind of incident or another every few years in houses -- a burned plug, a near-fire. It's a constant worry. It's really different over here, especially in UK houses with these bulky expensive connectors, ring main wiring architecture (two independent paths from each socket back to the electrical panel), and of course, half the current for the same wattage. It's just not an issue. I don't think I've ever even seen a burned BS1363 plug, not once.

Originally Posted by Auspicious

On the facts, not opinion, your view is incorrect.

The facts which demonstrate that have not yet been presented! Still hoping, though.

Originally Posted by Auspicious

. . . Then I respectfully suggest more attention to ventilation than you have, with attention to cold, dry make-up air. I used gas aboard in Sweden in late winter and three winters at dock in the Barents. I refer you to the lay publication I listed upthread and to http://scholar.google.com for HVAC-R discussions in professional journals.

. . . All carbon based fuels produce water by combustion. LPG in a cooker. Diesel in Seaworthy Lass’ Reflex heater. Water production is proportional to the hydrogen-to-carbon ratio in the fuel. Propane throws off 25% more water than diesel. I don’t consider that “HUGE.” Significant certainly but easily managed with proper ventilation. It has been in my experience and reflected in the literature. If Seaworthy Lass found the difference HUGE then there was some other factor, likely better ventilation of the Reflex combustion chamber than of the galley.

Well, obviously. The Reflex has a chimney; the combustion products are not put into the cabin. Totally different situation.


Condensation is not the only issue from dumping LPG combustion products into the cabin air. Those are fumes, which contain at least small amounts of CO and NOx, even when burning with a pure blue flame. More benign than fumes from diesel burning, but fumes.



My boat has 6 big dorade vents which I do not close in the winter, which is one reason why I have high heating demand, but good ventilation is crucial on a boat, so I don't mind. In addition, my boat has the supreme luxury of a powerful exhaust hood over the LPG cooker which vents through the transom. The exhaust hood makes a big difference, but even when running it, and even with the wind whistling through the dorades, the combustion products in the cabin are unpleasant, and I believe, unhealthy. Condensation is noticeable. This is a significant downside of LPG cooking.



The combustion products become less of a problem only in warm weather with the companionway and all of the hatches open. AND the exhaust hood going. But up here we don't have all that much weather like that.

Originally Posted by Auspicious

I agree with respect to resistive heat. When you lower a gas flame the diameter of flame reduces. Add choosing the proper size burner and there is reduced loss.

Sure, but efficiency is not an issue with gas, for the reasons discussed.

Originally Posted by Auspicious

Which leads to your comments about four burner cookers on boats. The biggest problems are balance and space. While I desperately miss my old six burner commercial cooktop my little two burner is quite convenient. We’re talking preferences now, not science. I like being able to squeeze a 12” skillet and a 2 qt pot on, or bridging both burners with my 14” skillet. A cast iron griddle fits over both.

The alternative is juggling too-small pots and pans to “fit” and having a kettle full of water to act as a counter balance. Bah! Try feeding four people for two weeks (I’m sure you have) when your “big” pan is 8” diameter. Bah! Again.

I've had boats with two burners, three, and four. I don't cook such elaborate meals, especially not in a seaway, so I am not particularly bothered by the number of burners. But I would like to have space for larger pans for sure. As you say it gets to be a real issue with a large crew so cooking larger quantities of food.

Originally Posted by Auspicious

Context. I’m looking at total risk, say risk of the boat burning. Since the risk of fire/explosion from LPG is lower than the risk of fire from electricity it is the subsidiary risk. Again, I don’t have the equations in my head. I remember how they work. I can look them up if you like. You can talk to an actuary in the back office of any insurance company and get a proper explanation.

I would appreciate it if you would, because I am not getting this at all.

Originally Posted by Auspicious

Anecdotes can be alarming. The explosion of the Space Shuttle Challenger could put one off space travel. It certainly reduced the enthusiasm of the US Congress for the shuttle program. That doesn’t mean they are good tools for decision making. While agree with “lies, damn lies, and statistics” they are darn handy things for getting emotional reactions out of a decision tree.

I don't think a boat explosion or two just in the UK, every year, year after year, is "anecdotal". I don't think you need more precision than that, to know that this is a very serious risk.


And incidentally, two total loss accidents with mass loss of life, in 100-odd flights, is also not "anecdotal". The Shuttle was a magnificent piece of engineering, but did not perform so well from the point of view of safety compared to other systems, like the Soyuz. To my eye, the Soyuz is the more beautiful system, with exquisitely conceived simplicity, at least as a human launch vehicle (granted the Shuttle did a lot more than carry humans). I would like my boat to be more like that, than like the Shuttle.

[Dsanduril]

Originally Posted by BlackHeron

Ohm's law and Joule's Law don't work that way.

Resistance over longer runs causes a LOT of voltage drop with high amp loads since 12 volt systems require fairly large currents to carry the power to loads that require it. The higher the current the more voltage drop as well as the longer the run the more resistance and again the more voltage drop..


Voltage drop produces or coincides with higher I²R losses (heat) at higher currents. The wire basically becomes a heating element, and it also requires even more current to flow through the circuit to compensate and balance the ohms law equation. More current produces yet more voltage drop and even more more heat in a downward death spiral if things get bad enough. This is one of the reasons the ABYC requires insulation on wires to be rated for 105C. That's more than hot enough to boil water. 12v is a poor voltage for high power loads and over any distance of wire more than a few feet.

I am (or was) a commercial electrician so I'm trying to phrase this in a way that a layman might understand it. Maybe an actual EE could explain it better than a working slob with dirt under his fingernails.

The problem I see with this whole debate is that a lot of people who don't even understand how electricity works are arguing why an electric stove (induction or conventional resistive elements) is better than gas.

Sorry, but 100A out of the battery is a 100A out of the battery - the battery simply doesn’t know or care about the distance to the load or the voltage drop. The load cares - the amount of power available at the load from that 100A certainly depends on the voltage at the load’s terminals. And that does depend on the distance, size of wire, and quality of connections. And when you factor in windlass cables sized for 10% voltage drop vs. and inverter (close to the battery) with a 91-93% efficiency you are looking at pretty much the same power available at your load either way for that hypothetical 100A battery current. And the battery still doesn’t care. The voltage sag is the same, the chemistry is the same, there is no difference to the battery.

As to the other note up thread about LA and C-rate, the ubiquitous Trojan T105, as an example, has a rated capacity of 225Ah at .05C and 185Ah at .2C. You “lose” 18% of your LA battery capacity simply by moving up to “high” discharge rates (with “high” being only .2C). Induction (or any other electric cooking) easily puts you into that realm for extended periods on most house banks.

[Dockhead]

Originally Posted by Dsanduril

. . . As to the other note up thread about LA and C-rate, the ubiquitous Trojan T105, as an example, has a rated capacity of 225Ah at .05C and 185Ah at .2C. You “lose” 18% of your LA battery capacity simply by moving up to “high” discharge rates (with “high” being only .2C). Induction (or any other electric cooking) easily puts you into that realm for extended periods on most house banks.

Yeah, that's right, and why I don't run electric cooking much off the batteries. 2000 watts is going to need about 90 amps from my batteries -- about on the 5 hour capacity line with my 450AH (20 hour capacity) lead bank. You don't want to be running 0.2C with lead acid batteries for long periods.



If I were going to build a boat without a gas system, I would want lithium like CatNewBee, and lots of it. Then you wouldn't worry about this particular issue.