Gas or spirit?

Some of us go through life with such a dismal attitude to any possible risks, that we make ourselves miserable, and some of us make the most of life, by accepting that there are risks in everything we do. It's our choice.
 
marie galante said:
...that there are many risks, some considered small, and others not so. Each individually may not amount to much, but added all together they comprise quite a significant likelihood of something about to spoil your whole day. It is generally accepted that the sensible way to proceed is to work to minimise each identifiable risk so that the aggregate remaining is, overall, reduced quite a lot.

Isn't that why we have e.g Lifejackets? Don't we choose when to wear them and when not? Isn't that why we set depth alarms at e.g 20 metres and not 2m...?

It's beneficial to have a sealed self-draining gas locker, but not clever if other kit stuffed in there - 'cos there's space' - can block up the drain holes. It's beneficial to have Coded supply hose that's well in-date, but not if it passes through several GRP/ply bulkheads without protective grommets, and where it cannot easily be inspected.

I've sailed on many boats, over the years, with gas systems that were fine when they were installed. Many of those boats had systems where the 'bits' had deteriorated with years of use and not been rectified to 'New Condition' - one had a bottle-mounted regulator so corroded it could not be turned off.

Seems to me that there are other boats around with system faults similar to the 'Lord Trenchard' - accidents just waiting for a place to happen.
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But I note that you have chosen not to include my last sentence. Of course there are risks, can you point me at anything in life that is risk-free? The prudent yacht owner/skipper inspects regularly and rectifies problems when they are minor ones.
 
We once had delivered to site a new 47KG propane cylinder, this sat in the yard and when one of the lads went out for a fag he noticed, as it had since rained and water was sat in the valve/ bottle threads that there was a lot of bubbling where the valve is screwed into the bottle. Fag put out, I rang the supplier who changed the bottle pronto.

Now i slop soapy water with a paint brush around the valves of any bottle we have since had, i dont know anyone else that does that and i have never found another leaky one, i probably wont cant help checking though !
 
VicS said:
Couldn't you screw the cap in rather than just let it empty ?
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I suppose we could have screwed the little screw - in carry handle, but since we were loading the boat onto the trailer and taking it home, I didn't want an unsealed gas cylinder in the car or in the boat for the journey. The carry handle is not I suspect intended to be the only seal on the cylinder, I don't even know whether it would have sealed it, and personally I didn't want to go anywhere near the thing.
 
vyv_cox said:
But I note that you have chosen not to include my last sentence. Of course there are risks, can you point me at anything in life that is risk-free? The prudent yacht owner/skipper inspects regularly and rectifies problems when they are minor ones.
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I chose not to quote that last sentence of yours < "The risk is very low indeed" > because I disagree. That's an opinion which, in your own admission, is based on no objective statistics. It's just an opinion.

Mine is different. As it is impossible for the likes of us to measure the concentration of spilt gas in a sailboat, and as the consequences of an explosive concentration being maiming, loss by fire, or worse, then MY training in risk assessment and mitigation tells me that it is a risk needing attention. My opinion. My choice. And, as others here such as 'Wooden Boat Fittings' agree, doing something about it is practicable and quite easy.

Now, Mr Cox, you may very well know your metallurgy, but you have no special qualification AFAIK in risk assessment, so your opinion is just that.

There are issues on board I may choose to be a little cavalier about - my choice - and they may well differ from yours. Gas spillage/leakage is not one of them.
 
This discussion has now become pointless, it all depends on your attitude to risk. Provided your gas system is in good condition and operated sensibly, the risk of explosion is very low as Vyv has said. The risk of occurrence is low but the consequences are severe.
With spirit type stoves there is a risk of fuel spillage. The risk of occurrence is higher but the consequences are slight.
Take your pick and weigh against convenience.
 
marie galante said:
I chose not to quote that last sentence of yours < "The risk is very low indeed" > because I disagree. That's an opinion which, in your own admission, is based on no objective statistics. It's just an opinion.

....
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There are plenty of objective statistics.
Many thousands of boats, very few fires or explosions.
Virtually every incident directly traceable to bad practice.

Once you extract the incidents related to gas installations designed, installed, maintained or operated by idiots, the risks are demonstrably numerically very low.
 
marie galante said:
I chose not to quote that last sentence of yours < "The risk is very low indeed" > because I disagree. That's an opinion which, in your own admission, is based on no objective statistics. It's just an opinion.

Mine is different. As it is impossible for the likes of us to measure the concentration of spilt gas in a sailboat, and as the consequences of an explosive concentration being maiming, loss by fire, or worse, then MY training in risk assessment and mitigation tells me that it is a risk needing attention. My opinion. My choice. And, as others here such as 'Wooden Boat Fittings' agree, doing something about it is practicable and quite easy.

Now, Mr Cox, you may very well know your metallurgy, but you have no special qualification AFAIK in risk assessment, so your opinion is just that.

There are issues on board I may choose to be a little cavalier about - my choice - and they may well differ from yours. Gas spillage/leakage is not one of them.
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Dear Marie,
The average age of contributors on this forum is probably quite high. "Risk Assessment" may now have paper qualifications that it didn't have in the past, but it has always existed. It used to be called "Common Sense". Unfortunately, with the proliferation of paper qualifications for all sorts of things, mainly in the furtherance of the avoidance of litigation, Common Sense has been forced to take a back seat. Life is full of risk. The fact that so many here are 'seniors' proves that we manage to assess and avoid risks quite well, without having the special training in risk assessment claimed by yourself.
One might ask for some figures: What proportion of boats suffer from gas explosions in any chosen time period?
 
marie galante said:
Now, Mr Cox, you may very well know your metallurgy, but you have no special qualification AFAIK in risk assessment, so your opinion is just that.
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True enough, but I have a great deal of experience working with high pressure gas systems and have participated in quite a few HAZOPs associated with them. None of which is very relevant to inspecting a few hoses and fittings in a boat installation, which requires no qualifications at all.
 
ghostlymoron said:
This discussion has now become pointless, it all depends on your attitude to risk.
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Since the decline of the "my kettle boils 30 seconds faster" and the "I need to cook everything at 200 degrees on full flame in nano seconds" argument - I'd agree with you.
 
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AFAIK, I don't possess any qualification in risk assessment although I have carried out many. At one company I worked with, it was considered necessary to identify a minimum of three risks which was quite difficult sometimes and brought the whole concept into disrepute IMH. You could always include 'cuts to fingers from paper' when using the photocopier.
NormanS said:
Dear Marie,
The average age of contributors on this forum is probably quite high. "Risk Assessment" may now have paper qualifications that it didn't have in the past, but it has always existed. It used to be called "Common Sense". Unfortunately, with the proliferation of paper qualifications for all sorts of things, mainly in the furtherance of the avoidance of litigation, Common Sense has been forced to take a back seat. Life is full of risk. The fact that so many here are 'seniors' proves that we manage to assess and avoid risks quite well, without having the special training in risk assessment claimed by yourself.
One might ask for some figures: What proportion of boats suffer from gas explosions in any chosen time period?
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Nicholas123 said:
Not true.Natural gas rises & there is also the issue of constituent parts/relationship to air.
If you plunged a match into a basement (or bilge) full it would'nt explode.The percentage of gas/air relationship has to be just right or you do not get combustion.
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If I've read you correctly, (not sure if your hypothetical bilge has LPG or methane in it.)
I think it would.... didn't you ever ignite gas in a cocoa tin with a hole in the lid? It happily burns until the mix is right and- pop.
So, your burning match, plunging through an increasingly concentrated mixture of air and LPG would find that sweet spot at some point and do what comes naturally...
 
Have been looking at my current set up and was going to swap over to spirit but most of mine was replaced in copper a while back so will replace the hose bits and invest in a marine grade valve, fit a drain in the gas locker with a valve to close in a heavy following sea and with good practice and maintenance see no problems... we used it on fishing boats I worked on daily for years and as above good practice and maintenance no problems... in the end down to individual choice and thought processes/priorities I guess.
 
MOBY2 said:
Have been looking at my current set up and was going to swap over to spirit but most of mine was replaced in copper a while back so will replace the hose bits and invest in a marine grade valve, fit a drain in the gas locker with a valve to close in a heavy following sea and with good practice and maintenance see no problems... we used it on fishing boats I worked on daily for years and as above good practice and maintenance no problems... in the end down to individual choice and thought processes/priorities I guess.
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Aim to comply with the Boat safety scheme and you wont go far wrong.
SEE HERE

You ought to test the system when you are done.
It may now be out of date now but the tests described HERE should ensure that you have a sound leak free system.

I think a valve in the bas bottle locker drain would be frowned upon!
 
Thanks VicS, will follow the advice in the links... will see about the valve just don't want water filling up one of the aft lockers.

Thanks again for the help
 
I'm sure my gas locker will get quite a lot of water in it at times. It is a midships starboard side deck locker, with the drain just above the WL. If I'm close hauled on port tack, in a fresh breeze, and down to the gunwale, there must be water in it, but I wouldn't consider fitting a valve on the drain, as it would defeat the purpose.
 
ghostlymoron said:
... it all depends on your attitude to risk... Take your pick and weigh against convenience.
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Now we're at the nub of things. A simple common-sense approach to risk management can be taken by following the steps in this flow-chart (used by permission: I am an associate of the company) --

risk-mgmt.jpg

In the terms of this diagram, we agree that the possibility of an explosion due to the presence of gas in the bilges is a material risk (blue diamond). Probably you can't do a great deal about reducing either the severity or the impact of an explosion should it occur* (second and third green diamonds), but if you do want to use gas, then by following some of the actions mentioned in earlier posts (first green diamond and yellow rectangle) you can reduce the probablity that an explosion will occur in the first place. That is to say, you've managed the risk and now you're happy to live with it. But note that the risk still exists -- as long as you're using gas you can never reduce the risk of a gas explosion to zero.

But you can remove the risk altogether by following the same path through the diagram to the first green diamond and yellow rectangle, and choosing as a strategy the removal of the gas installation altogether. This is the only way to entirely remove the risk of a gas explosion.

As said before, you pay your money and take your choice.

Mike
* You can perhaps do so to some extent during construction, by using non-inflammable materials, providing collision bulkheads, and so on. I'm assuming here that we're referrring to existing vessels.
 
Wooden Boat Fittings said:
But you can remove the risk altogether by following the same path through the diagram to the first green diamond and yellow rectangle, and choosing as a strategy the removal of the gas installation altogether. This is the only way to entirely remove the risk of a gas explosion.
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A moment on google show electrical problems to cause the majority of fires on boats, also petrol onboard as a significant hazard - following your risk assessment process, does this mean you have a boat with no outboard and no electricity?
 
vyv_cox said:
I have composed and then deleted my response to this diagram in the interests of forum harmony. Let us remember that we are dealing with a couple of lengths of rubber hose, some copper pipe and fittings.
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Funnily enough, I did exactly the same, with the same thoughts. Isn't the delete button wonderful. :D
 
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