Hot water on demand?

[Jim Cate]

Originally Posted by smj

I know all but one on demand water heater doesn't meet ABYC standards, but what about other boat building standards? Do they meet standards in Europe or Australia? I still can't see much difference between running a well vented stove or a well vented propane water heater.

SMJ, there are two separate hazards associated with the use of the propane water heater: combustion products and LPG explosion hazards. Folks tend to get these two confused in their arguments.

IMO (and we have used domestic flow through heaters for nearly thirty years now on our cruising boats) the combustion product issue (CO production and contamination of breathing air) is completely addressed by venting the heater to the outside world. When one does this, it is safer (less likely to introduce CO into breathing air below decks) than a cook stove which is not vented at all in any boat I have ever seen.

The issue of LPG leakage and collection in the bilge is dependent upon the usage method for the heater. If it is left "on", with LPG under pressure at its internal valve, there is the possibility of valve or gas line failure and subsequent leakage. That hazard is roughly equivalent to leaving the LPG solenoid valve on one's stove "on" when the stove is not in use, a habit that most find easy to avoid. But if one only turns on the valve supplying the heater with LPG when one is about to use the hot water, and turns it off when through, I can not see that the heater is any more hazardous than the ubiquitous propane cooker found in very many cruising boats around the world. This is the procedure that we have used on our boats, and while it is less convenient than leaving it on full time, it isn't a big deal to us.

A few respondents here have vowed to not have propane on board for any use, quoting horrendous accidents to support their views. That is surely a valid decision for them, but not one that suits all cruisers. To me, it is pretty similar to deciding to never ride in an automobile because there are many terrible accidents with death and dismemberment resulting. A recognized risk, but one that one can mitigate by careful usage, good installations and a LPG sniffer in the bilge just in case!

BTW, I personally feel that the proposal to use the disposable one pound containers to be more hazardous than the permanent installations described above. I would not use such a plan myself.

Jim

[smj]

Thanks Jim, you have clarified what I thought. We have owned 4 boats with the propane on demand water heaters and never had a problem. We have always installed them where there is good ventilation, our current one is installed close to the stove and has a large opening port above. On our current boat we haven't installed a propane solenoid. As on previous boats, when finished cooking or showering we shut the propane of directly at the tank. Pretty sure it's not up to ABYC standards but pretty foolproof if you are in the habit.

[Dockhead]

Originally Posted by uncle stinkybob

Not true, basements. In 1971 a restaurant my dad was part owner of exploded, caused by natural gas leak in the basement. A neighboring hotel was also destroyed in the blast. A refer unit switching on caused ignition. 38 injured. A house the same year I believe exploded injuring 1.

https://www.google.com/url?sa=t&rct=...yv8YD_HOHQnNYg

Sure. But natural gas is lighter than air. Which makes it 1000x safer than propane. But even natural gas, of course, can be dangerous!

[Dockhead]

Originally Posted by Jim Cate

SMJ, there are two separate hazards associated with the use of the propane water heater: combustion products and LPG explosion hazards. Folks tend to get these two confused in their arguments.

IMO (and we have used domestic flow through heaters for nearly thirty years now on our cruising boats) the combustion product issue (CO production and contamination of breathing air) is completely addressed by venting the heater to the outside world. When one does this, it is safer (less likely to introduce CO into breathing air below decks) than a cook stove which is not vented at all in any boat I have ever seen.

The issue of LPG leakage and collection in the bilge is dependent upon the usage method for the heater. If it is left "on", with LPG under pressure at its internal valve, there is the possibility of valve or gas line failure and subsequent leakage. That hazard is roughly equivalent to leaving the LPG solenoid valve on one's stove "on" when the stove is not in use, a habit that most find easy to avoid. But if one only turns on the valve supplying the heater with LPG when one is about to use the hot water, and turns it off when through, I can not see that the heater is any more hazardous than the ubiquitous propane cooker found in very many cruising boats around the world. This is the procedure that we have used on our boats, and while it is less convenient than leaving it on full time, it isn't a big deal to us.

A few respondents here have vowed to not have propane on board for any use, quoting horrendous accidents to support their views. That is surely a valid decision for them, but not one that suits all cruisers. To me, it is pretty similar to deciding to never ride in an automobile because there are many terrible accidents with death and dismemberment resulting. A recognized risk, but one that one can mitigate by careful usage, good installations and a LPG sniffer in the bilge just in case!

BTW, I personally feel that the proposal to use the disposable one pound containers to be more hazardous than the permanent installations described above. I would not use such a plan myself.

Jim

I think this is a pretty solid analysis.

Note the mention of the LPG sniffer in the bilge -- don't think the OP was thinking about that. Certainly adds a great deal of safety.

I also believe that LPG can be used on board RELATIVELY safely, with good installation, good maintenance, bilge sniffer, good procedure. But even then, the risk is not that small.

Why bother with all that? I have an LPG stove on my present boat, and I don't lie awake at night worrying about it, but if you have any reasonable alternative, why would you go to all the trouble you need to go to, to make LPG RELATIVELY safe, and then still live with the residual risk? Plus the hassle of sourcing gas which has a different type of bottle in every country?

My next boat will definitely have electric cooking, and no LPG on board at all. Why anyone would extend this problem to water heating, when there are so many safe ways to make hot water, is beyond me.

If I were the OP, I would put in a normal calorifier with an engine coolant loop, so he can make hot water from either shore/generator power, or by running the engine, like 99% of cruisers do. It's not rocket science, nor all that expensive. For a couple hundred bucks and a weekend of installing, you can add a used hydronic truck heater, and make hot water by burning diesel fuel, as a third method.


Disposable fuel cans on a boat -- madness. If you MUST use LPG to make hot water, then for God's sake at least use a normal propane installation, like Jim does.

[smj]

But what do you do if your outboard powered with no generator? Why would you want an electric stove when you have to fire up a generator whenever cooking a meal? I'm pretty sure a little common sense, a decent installation that doesn't leak and praying every time you fire up your propane stove or water heater will lead to a safe system[emoji38]. What percentage of cruising boats have propane stoves, maybe 95%? And I can't think of a catastrophic failure that I've seen, though I'm sure there have been some.

[Dockhead]

Originally Posted by smj

But what do you do if your outboard powered with no generator? Why would you want an electric stove when you have to fire up a generator whenever cooking a meal? I'm pretty sure a little common sense, a decent installation that doesn't leak and praying every time you fire up your propane stove or water heater will lead to a safe system[emoji38]. What percentage of cruising boats have propane stoves, maybe 95%? And I can't think of a catastrophic failure that I've seen, though I'm sure there have been some.

Yes, of course -- if you don't have a good electrical supply, then electric cooking is not really an option. I was not suggesting that it is a solution for everyone. Alcohol has its own drawbacks; diesel stoves exist but are stinky and expensive. CNG requires a pressure vessel and has become almost impossible to get. So yes -- you end up with propane as the best of a bad bargain.

For me, "decent installation" includes following ABYC to the letter, plus most definitely a propane sniffer in the bilge (if I were writing them, ABYC would require that, too).


I'm not sure I would say "common sense", though -- it's not that common. Some people who think they have common sense, think propane rises, and think a pound of it is not too explosive, so nothing to worry about. Much better to have a very clear set of rules and procedures, so we don't have to rely on this "common sense".

[darylat8750]

US Propane Usage Statistics
14,300,000
1,040,000
240,000
456,000
81,000
660,000
110,000
6,880,000
47,000,000

Residential Propane Customers
Commercial Propane Customers
Industrial Propane Customers
Propane Forklift Customers
Agricultural Propane Customers
Fleet Propane Customers
LPG Standby Generator Customers
Households Heating With Propane
Propane Grill Users

I can't figure out how to make these numbers line up.

In excess of 14 million propane customers in the us and more than 6 million households are heated by propane. Doesn't seem to be a national emergency .

What Jim said in post #76 makes great sense to me.

I too would be scared of the one pound canisters .

[smj]

Originally Posted by Dockhead

Yes, of course -- if you don't have a good electrical supply, then electric cooking is not really an option. I was not suggesting that it is a solution for everyone. Alcohol has its own drawbacks; diesel stoves exist but are stinky and expensive. CNG requires a pressure vessel and has become almost impossible to get. So yes -- you end up with propane as the best of a bad bargain.

For me, "decent installation" includes following ABYC to the letter, plus most definitely a propane sniffer in the bilge (if I were writing them, ABYC would require that, too).


I'm not sure I would say "common sense", though -- it's not that common. Some people who think they have common sense, think propane rises, and think a pound of it is not too explosive, so nothing to worry about. Much better to have a very clear set of rules and procedures, so we don't have to rely on this "common sense".

What are the regulations regarding the use of propane in the UK and Europe? Any regulations regarding the use of on demand water heaters? If the insurance companies had their way we would be regulated out of boat use!

[Pete7]

Originally Posted by smj

What are the regulations regarding the use of propane in the UK and Europe? Any regulations regarding the use of on demand water heaters? If the insurance companies had their way we would be regulated out of boat use!

Good question, there are quite strict rules for the use of gas on inland boats typically used on the UK canal system. These rules are enforced with regular inspections every 5 years I think:

Boats with gas | Boat Safety Scheme | Go Boating - Stay Safe

Commercial boats even charter yachts however do have a strict inspection regime annually by the owner and 5 yearly by the licencing body:

Commercial Craft Regulations | Regulations | Knowledge & Advice | Knowledge & Advice | RYA

For boats used for pleasure at sea, not sure there are any other than perhaps the CE rating stuff and SOLAS.

The UK tends to have a more relaxed attitude to rules / laws than say the US. The govening body for sailing is the RYA who prefer an learning approach rather than legislative approach. If you have a big enough credit card you can buy a new boat with no qualifications and proceed across the Atlantic. No one is going to inspect your life jackets or see if your loo pumps overboard.

The EU has mumbled about licencing from time to time but nothing other than voluntary qualifications applies to private yachts in the UK other than SOLAS requirements that I am aware of.

Europe is different, with each country having its own rules. I have had the French coasties give my rib a worrying look because we had burst a tube section. They left us alone because we were all wearing life jackets and the tube was a minor problem and didn't affect the seaworthyness of the boat.

Pete

[Dockhead]

Originally Posted by smj

What are the regulations regarding the use of propane in the UK and Europe? Any regulations regarding the use of on demand water heaters? If the insurance companies had their way we would be regulated out of boat use!

There are almost no regulations about anything on boats in the UK, at least boats under 13.7 meters. You are not required to even register them. There are no taxes, no licenses are required, and no requirement to carry any particular equipment.

AFAIK, the rules about gas safety are entirely voluntary. I think most reputable boat builders in the UK follow ABYC. Several people are killed every year in the UK in propane explosions on boats.

[Pete7]

Originally Posted by smj

What are the regulations regarding the use of propane in the UK and Europe? Any regulations regarding the use of on demand water heaters? If the insurance companies had their way we would be regulated out of boat use!

However, as a Civil Servant you now have me thinking, perhaps the UK should have annual inspections, licences and taxes for light houses etc. This will of course require a huge new government department and an army of civil servants to manage. Its a good suggestion, I will raise it with my boss on Monday

Pete

[smj]

Thanks for the links. It appears that the U.K. regs don't meet ABYC. We have owned a few British built boats and I now remember that there was one central propane line that had T fittings for each appliance run of it. Each appliance did have a separate shut of valve though. Funny how different countries have different and more stringent regulations than others. My personal belief is the ABYC is driven by the insurance companies, and we all know less claims means more profits.

[smj]

Originally Posted by Pete7

However, as a Civil Servant you now have me thinking, perhaps the UK should have annual inspections, licences and taxes for light houses etc. This will of course require a huge new government department and an army of civil servants to manage. Its a good suggestion, I will raise it with my boss on Monday

Pete

Ah, bigger government means more jobs!

[Cheechako]

Originally Posted by uncle stinkybob

Not true, basements. In 1971 a restaurant my dad was part owner of exploded, caused by natural gas leak in the basement. A neighboring hotel was also destroyed in the blast. A refer unit switching on caused ignition. 38 injured. A house the same year I believe exploded injuring 1.

https://www.google.com/url?sa=t&rct=...yv8YD_HOHQnNYg

Natural gas a problem? Nah....:>) ... one of a few in Seattle last year.

[uncle stinkybob]

Originally Posted by Cheechako

Natural gas a problem? Nah....:>) ... one of a few in Seattle last year.

WOW, that place got leveled. Looks more like a 500 lb dumb bomb strike.
A large trawler here at J.W. marina blew up 4 years ago, propane. The boat was gone at the water line, owner's body was floating in the marina. Damaged several boat's around it. The fail storys I hear about gas use on boats keeps me very aware of my propane system and I check it all the time. I don't feel it's a install and forget kind of item.