WindFinder
regular
Reged: 03/03/2008
Posts: 291
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Quote:
Father and son in an apparently well sorted yacht strike an object in the outer Thames at night ( in June) - boat starts to rapidly sink, 5 - 10 mayday calls gained no response two flares likewise despite ships only a few miles away. Stepped up into the liferaft at 0210 BST, fired flares when commercial ships in the vicinity but none respond, eventually recovered at 1010 BST. Without a liferaft these two would be dead (despite being in coastal waters etc etc).
Why would a dinghy not have saved their lives? Was it cold? Was there a demon sea state? They were at sea in the LR for 8 hours - depending on the wind direction in a dinghy they could have probably rowed ashore!
Indeed in June they'd probably have lasted for hours in the water, if they'd had a waterproof VHF or Epirb they could maybe even have managed without an emergency craft of any kind.
I'd be very interested to have the additional risk of not carrying a LR quantified. The current debate is too wooly to be useful.
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alant
regular
Reged: 30/05/2001
Posts: 1907
Loc: UK - Solent region
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I quote the MAIB because it has a statutory duty to investigate any accident in UK waters or involving UK vessels.
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Only vessels > 8 metres
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Fireball
regular
Reged: 15/11/2004
Posts: 7477
Loc: Chichester
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So does that make a LR essential for those vessels the MAIB doesn't investigate?
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DavenHelen
regular
Reged: 06/09/2005
Posts: 555
Loc: UK, Lancashire
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Quote:
With regards to yachts foundering and liferaft usage it is completely irrelevant because the incidents are less that 2 a year - and some years none. So it does not matter whether it is 1000 or 100000 movements or 1 million or 10 million miles, the probability of a foundering occuring is statistically unmeasurable.
Let me understand this, you are saying that if the whole leisure fleet does 10,000 between them in a year and has 1 foundering incident it is the same as if they do 1,000,000 miles?
You can measure the incidents but you have no data on usage involved. For road vehicles the total annual mileage is around the 300bnmark, with serious accidents at 1 every 10m miles travelled (rough figures based on a quick trawl). With those odds against having a serious accident, maybe we shouldn't bother with seatbelts and airbags.
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Dave
"There are 10 types of people in the world - those who understand binary, and those who don't".
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Tranona
regular
Reged: 10/11/2007
Posts: 1377
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No, what I am saying is that in any one year the probability could be absolutely zero. If there were 1 it would be 1 in x, still close to zero. Unlike road accidents where there are thousands to analyse the number of yachts foundering is so small and in circumstances that will not affect the vast majority of yachtsmen, that statistical analysis is not appropriate. This is why you have to consider and learn from each individual event - then you will get the themes that I have identified.
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DavenHelen
regular
Reged: 06/09/2005
Posts: 555
Loc: UK, Lancashire
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Quote:
No, what I am saying is that in any one year the probability could be absolutely zero.
[pedant]
The number or percentage could be 0.
[/pedant]
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Dave
"There are 10 types of people in the world - those who understand binary, and those who don't".
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Moonfire
regular
Reged: 09/11/2004
Posts: 621
Loc: Medway, UK
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Weather a squally SW F6 -7 veering W5. A dinghy might have been enough (I doubt it in this case) but I suggest you read the article to get the skipper's version and then pass comment.
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Tranona
regular
Reged: 10/11/2007
Posts: 1377
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I have now read this case. The reason that it does not show up in the MAIB reports is because it is a Dutch yacht and the incident occurred outside UK territorial waters. This does not, of course make the experience any less valid and confirms my findings that liferafts are very effective in organised evacuations of slowly sinking yachts, particularly in relatively benign conditions.
There is, of course far more data available worldwide, but it is not necessarily accessible or comparable. A similar review of the French data (where liferafts are compulsory) would be an obvious start as would the US Coastguard. However, this is way beyond the resources of a unfunded curious yachtsman such as me.
Picking up on a couple of other points as the potential use of a dinghy (perhaps part inflated) is suggested as an alternative to a liferaft. In this sort of situation it may well work, although as far as I know there are no recorded incidents from which one can draw any conclusions. But organised evacuations are a minority and in the extreme cases, where even purpose designed rafts have problems, what chance a half inflated dinghy?
The Dec 2004 YM also has two sobering articles on liferafts. They do not give one much confidence in the product. One new Zodiac failed to inflate; it was a Zodiac that failed to inflate in the Megawat incident; I have a Zodiac on my boat. Maybe I should stick to the day job.
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Moonfire
regular
Reged: 09/11/2004
Posts: 621
Loc: Medway, UK
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Quote:
"Moral Panic" is a well known concept in mass communications exemplified by such incidents as Devil worship in the Orkneys and systemic child abuse in Lancashire, none of which had any basis in fact. Would be a pity if such phenomena spread into Yachting.
I suggest you read the article, which was factual.
I find the link of whether or not to by a liferaft based on factual data with the two exmples you give of 'moral panic' tenuous in the extreme.
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Tranona
regular
Reged: 10/11/2007
Posts: 1377
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Pedant
Probability is the ratio of events to sample (or population) size. You can express it as a ratio (x in y) or if you have a £2 calculator from Tescos you can turn it into a percentage. The concept and meaning is exactly the same.
So if there are 2 incidents each year and 10000 voyages, the probability expressed as a percentage is .0002%. If it halves next year to 1 and voyages stay the same it is .0001%. Both are close to zero. If the number of voyages halves to 5000 and there are two incidents the percentage rises to .0004%, still close to zero.
The number of incidents is not related to the number of voyages or number of miles. They are not randomly distributed across the population, but only occur in a narrow range of specific circumstances.
None of the key conditions for statistical analysis using probabilities therefore exists.
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