does anybody know a bit about liferafts?

Resolution said:
"I want to be an inventor when I grow up." Maybe the message is in the last four words.
In the meantime let's welcome Sailingsaves to the forum as a new source of ideas and subject matter, to stir up all us crusty old f4rts.
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This is not the lounge you know.
However, indeed it is of interest to note that the ones that called me a liar etc were on approx average (according to their profiles) aged 70.

Sabre 426, £170 000 - nice boat
 
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Sailingsaves said:
Not the most pleasant of replies to read of an evening.

.
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I really think you have a problem

Perhaps your " doctorate" has given you a false sense of superiority. However, your attitude to slight criticism (actually I was only offering a different opinion) suggest that If you cannot accept alternative views but remain self centred it would make your final assertions unreliable.

If you care to read my post I felt that the Spinlock (could have been a wide number of manufacturers) was an improvement on the Mae West. Can you really imagine the buying public choosing one over the current range.
You seem to object to the comparison with the Mae West. I would suggest that it was made in the thousands & possibly in greater numbers per annum than any modern make. It was a part of history & should not be dis
carded as irrelevant just because it proves you wrong. As for release valve I think I would be more interested in getting air in rather than out. Would you have preferred I had used the later, but now defunct, Functional brand, used at the time by the RNLI. Yes been in the water with one of those as well- but only once as it got the bin treatment immediately after

As for Crewsaver, can you really suggest that the early PVC covered string fastened affairs that rode up the body when immersed or leaked & then smelled because it could not be dried out was better than the modern buoyancy aids that fit better, have zips & belts, better fabric so they dry out quicker, remain in place when immersed & are generally more comfortable
I have actually been in the water with old Crewsaver & modern aides many times so I think I am qualified to comment. The same goes for the Mae West. Both on & in the water it was far more uncomfortable ( I can speak from experience) than my automatic inflating Spinlock. if made in the same quantities, I suspect it would cost a lot more as well. I do agree ,however, that the Spinlock comfort could be better in the water

I made a joke (perhaps you were too blind to see it) that the Kapok LJ would make a better fender than a plastic bottle. I did not realise that you were the one that suggested bottles as fenders . In reply you then tried to hide behind gobbledegook about the merits of plastics. Just as one might expect really

Previously, i have never objected to you expressing your opinion. But in return I am entitled to mine. Perhaps in the future we can keep it that way.
 
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Daydream believer said:
I really think you have a problem

Perhaps your " doctorate" has given you a false sense of superiority. However, your attitude to slight criticism (actually I was only offering a different opinion) suggest that If you cannot accept alternative views but remain self centred it would make your final assertions unreliable.

If you care to read my post I felt that the Spinlock (could have been a wide number of manufacturers) was an improvement on the Mae West. Can you really imagine the buying public choosing one over the current range.
You seem to object to the comparison with the Mae West. I would suggest that it was made in the thousands & possibly in greater numbers per annum than any modern make. It was a part of history & should not be dis
carded as irrelevant just because it proves you wrong. As for release valve I think I would be more interested in getting air in rather than out. Would you have preferred I had used the later, but now defunct, Functional brand, used at the time by the RNLI. Yes been in the water with one of those as well- but only once as it got the bin treatment immediately after

As for Crewsaver, can you really suggest that the early PVC covered string fastened affairs that rode up the body when immersed or leaked & then smelled because it could not be dried out was better than the modern buoyancy aids that fit better, have zips & belts, better fabric so they dry out quicker, remain in place when immersed & are generally more comfortable
I have actually been in the water with old Crewsaver & modern aides many times so I think I am qualified to comment. The same goes for the Mae West. Both on & in the water it was far more uncomfortable ( I can speak from experience) than my automatic inflating Spinlock. if made in the same quantities, I suspect it would cost a lot more as well. I do agree ,however, that the Spinlock comfort could be better in the water

I made a joke (perhaps you were too blind to see it) that the Kapok LJ would make a better fender than a plastic bottle. I did not realise that you were the one that suggested bottles as fenders . In reply you then tried to hide behind gobbledegook about the merits of plastics. Just as one might expect really

Previously, i have never objected to you expressing your opinion. But in return I am entitled to mine. Perhaps in the future we can keep it that way.
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If anything, I have an inferiority complex actually, which to those in the know means that such sufferers take criticism badly.

If you had researched any of my previous posts (I do this and just thought it was natural thing that all people do) you would have seen that I do have more than one problem; possibly post traumatic stress disorder and depression (so the experts think). I certainly do not think myself superior, but I do anger quickly if I feel wrong done by (for numerous reasons). I perceived you were making fun of me - read on if you were not. Charles Reed definitely calls me a liar - (I have no idea why he thinks me a liar) and my reaction to his post is there.

The thread was going really well up until post #28 page 3

One person stated "interesting question". There is very little info easily available about liferafts. I learned a lot from the replies up to #28

If ( in post #28) you did not know I was the poster of the coke bottle fender thread then you are owed an apology because it was that statement that made your post seem one of ridicule, the rest was simply you disagreeing (which is fine of course)

So, if you really did not know I was the poster of the coke bottle fender thread then I offer my apology, as of course you are entitled to "beg to differ" even in the extreme of not comparing like to like (inflatable to foam etc)

As to relief valves: All 3 different Beaufort liferafts I am examining have them (all videos I have seen show the vales expelling excess gas too) and (in my opinion shall we say as I have not published the methodology of my research and tests) the good old INFLATABLE lifejackets have a relief valve and the modern £300 lifejacket has one.

These valves are surely realised as important for ensuring the air does indeed get into the lifejacket as you say (i.e. the cylinders are designed to produce MORE than enough gas to inflate. If this was not so, the bladders may not inflate enough). But there needs to be a mechanism to allow the excess gas to expel before bursting the bladder.

Hence my conclusion that well designed lifeJACKETs and liferafts have good relief valves and a good supply of gas.

Let us hope that the proposed article about liferafts is published.

The youtube video showing a lifejacket bursting at the seams is no longer on youtube, but I found these. All interesting if different ways. The lady with a Scottish accent (I think) and lovely laugh is adorable. I didi not know about the fungal attack on bladders creating tiny leaks.

https://www.youtube.com/watch?v=WsMnrP-ZqaQ
4mins 50 secs in.


https://www.youtube.com/watch?v=2LpKlkNxaMs

https://www.youtube.com/watch?v=Tb4uxZYb-Sk


https://www.youtube.com/watch?v=7UbAEitduog

https://www.youtube.com/watch?v=9Pe-HME1S5U

https://www.youtube.com/watch?v=JWcrKYi5Wqk

http://www.ybw.com/forums/showthread.php?28877-Do-you-trust-your-lifejacket
POST #21 IS FUNNY

http://www.ybw.com/forums/showthread.php?41012-Lalizas-lifejacket-failure

http://www.ybw.com/forums/showthread.php?402319-Check-your-LJs!&highlight=lifejacket


I don't know why you posted about buoyancy aids and the following because I never mentioned suchlike and I would have thought I had made it abundantly clear that I am comparing modern inflatable to old inflatable.
Daydream believer said:
As for Crewsaver, can you really suggest that the early PVC covered string fastened affairs that rode up the body when immersed or leaked & then smelled because it could not be dried out was better than the modern buoyancy aids that fit better, have zips & belts, better fabric so they dry out quicker, remain in place when immersed & are generally more comfortable
I have actually been in the water with old Crewsaver & modern aides many times so I think I am qualified to comment.
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Sailingsaves said:
There is very little info easily available about liferafts.
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Perhaps you should carry out some serious "research". Your statement is simply not true. There is masses of information available about liferaft design, manufacture and use including international standards, regular reports in magazines on the latest developments, including simulated tests and reports from bodies such as the MAIB on performance of liferafts in real emergency situations.

The heirarchy of types of rafts is well established and the challenges of designing and building them to be effective are well known.

It would be interesting to know what you see as the deficiencies in current designs and your suggestions for improvements.
 
Tranona said:
Perhaps you should carry out some serious "research". Your statement is simply not true. There is masses of information available about liferaft design, manufacture and use including international standards, regular reports in magazines on the latest developments, including simulated tests and reports from bodies such as the MAIB on performance of liferafts in real emergency situations.

The heirarchy of types of rafts is well established and the challenges of designing and building them to be effective are well known.

It would be interesting to know what you see as the deficiencies in current designs and your suggestions for improvements.
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Thank you to all the posters that supplied great info. I will be visiting a service centre to learn more and hope I can share anything learned / designed or built with you one day.

Hello to Tranona, not sure why you have speech marks around "research", but here goes:
This was the OP:
"THIS IS THE QUESTION AND point of my post (because I cannot examine a £1k liferaft)
Is the price differential to do with the design / construction of the raft or is it purely the contents of the raft?
Anyone owned both or just happen to know the answer"

You have not answered my question but have asked one of your own, the reply to which is at the end of this post.
It is the truth, the whole truth and nothing but the truth. No salt applied.

You have stated there is masses of info out there.
Could you give a few web links pertaining to the OP?

I have scoured the web for a video showing the mechanical coupling of the bottle to the raft (any raft) and found none.
which rafts use steel (painted) bottles?
which use aluminium alloy?
which use the light and strong carbon fibre bottles?

Which rafts use what material?

The Beaufort MK 15 and MK 18 both use a feeble coat-like material may even be coated nylon.

The Beaufort 4 man uses something similar to hypalon for tubes.

Can replacement bottles for MK 18 liferafts be purchased (they are a one use only bottle, pierced by a needle - muck like lj mechanism)? All service agents said to ask survitech (now owners of Beaufort). I am in contact with Survitech.

4 man liferaft bottles of the vintage I am examining can easily be refilled.

That is just a small number of the things I want to find out. The 3 co2 mechanisms on the 3 rafts made by the same company are all different and I want to examine why this is so.

As to your question, I think many of the posters that answered the OP indicate some of the deficiencies; such as cheaper rafts being inverted and that the more expensive Viking brand is designed to self-right. This was useful news to me and I was grateful for the info.

Another deficiency, since you ask, is the fact that some rafts do not inflate when deployed.

When I used to read magazines I remember at least one story of the painter becoming detached from boat and raft twirling away with the storm (due to human error in tying knot? or breakage of cordage? There is a simple solution to ensure that never happens and is foolproof so even a non-sailor could not allow it to happen.

That improvement and others that I am contemplating cannot be divulged until the IP is protected and I have tested them with the aforementioned prototype.

PS for anyone interested in at least one finding about lifeJACKETS, see the attached photos of a modern(ish) Baltic lj that really should be scrapped. I purchased it second hand. I liked the fleece collar for Summer use and the outer protective sleeve - Seago lifejackets do not have a protective sleeve; the outer material is part of the bladder, so abrasion against boat etc, whilst wearing it could lead to a hole in bladder.
It explains why some manufacturers state lifejackets should be renewed after 5 years (I think this is poor)
The bladder material of the Baltic upon folding has creased and along some of the creases almost worn holes in the bladder material.
The strip of green military tape covers a bad crease and hole that I repaired with special glue, bladder material cut from mechanism protection sleeve (good design idea) and then green military tape just as a belt and braces job. For me, it will do for one of my particular types of sailing. I will not sell it or let anyone else use it. It does not decrease in pressure after 48 hours so I am content it meets my minor needs. I have a crewsaver auto for when I go solo out of sight of land.

An extremely good thing I learned (from youtube) was the fungal attack of bladders leading to leakage at high (working) pressure and I am now using a mild mildew remover (I think it was VicS who suggested Kleeneze) on a test patch of one of the lifejackets and although I always rinse and dry my ljs, I will pay attention to this easily averted fungal attack.
View attachment 47942
 
Sailingsaves said:
Thank you to all the posters that supplied great info. I will be visiting a service centre to learn more and hope I can share anything learned / designed or built with you one day.

Hello to Tranona, not sure why you have speech marks around "research", but here goes:
This was the OP:
"THIS IS THE QUESTION AND point of my post (because I cannot examine a £1k liferaft)
Is the price differential to do with the design / construction of the raft or is it purely the contents of the raft?
Anyone owned both or just happen to know the answer"

You have not answered my question but have asked one of your own, the reply to which is at the end of this post.
It is the truth, the whole truth and nothing but the truth. No salt applied.

You have stated there is masses of info out there.
Could you give a few web links pertaining to the OP?

I have scoured the web for a video showing the mechanical coupling of the bottle to the raft (any raft) and found none.
which rafts use steel (painted) bottles?
which use aluminium alloy?
which use the light and strong carbon fibre bottles?

Which rafts use what material?

The Beaufort MK 15 and MK 18 both use a feeble coat-like material may even be coated nylon.

The Beaufort 4 man uses something similar to hypalon for tubes.

Can replacement bottles for MK 18 liferafts be purchased (they are a one use only bottle, pierced by a needle - muck like lj mechanism)? All service agents said to ask survitech (now owners of Beaufort). I am in contact with Survitech.

4 man liferaft bottles of the vintage I am examining can easily be refilled.

That is just a small number of the things I want to find out. The 3 co2 mechanisms on the 3 rafts made by the same company are all different and I want to examine why this is so.

As to your question, I think many of the posters that answered the OP indicate some of the deficiencies; such as cheaper rafts being inverted and that the more expensive Viking brand is designed to self-right. This was useful news to me and I was grateful for the info.

Another deficiency, since you ask, is the fact that some rafts do not inflate when deployed.

When I used to read magazines I remember at least one story of the painter becoming detached from boat and raft twirling away with the storm (due to human error in tying knot? or breakage of cordage? There is a simple solution to ensure that never happens and is foolproof so even a non-sailor could not allow it to happen.

That improvement and others that I am contemplating cannot be divulged until the IP is protected and I have tested them with the aforementioned prototype.

PS for anyone interested in at least one finding about lifeJACKETS, see the attached photos of a modern(ish) Baltic lj that really should be scrapped. I purchased it second hand. I liked the fleece collar for Summer use and the outer protective sleeve - Seago lifejackets do not have a protective sleeve; the outer material is part of the bladder, so abrasion against boat etc, whilst wearing it could lead to a hole in bladder.
It explains why some manufacturers state lifejackets should be renewed after 5 years (I think this is poor)
The bladder material of the Baltic upon folding has creased and along some of the creases almost worn holes in the bladder material.
The strip of green military tape covers a bad crease and hole that I repaired with special glue, bladder material cut from mechanism protection sleeve (good design idea) and then green military tape just as a belt and braces job. For me, it will do for one of my particular types of sailing. I will not sell it or let anyone else use it. It does not decrease in pressure after 48 hours so I am content it meets my minor needs. I have a crewsaver auto for when I go solo out of sight of land.

An extremely good thing I learned (from youtube) was the fungal attack of bladders leading to leakage at high (working) pressure and I am now using a mild mildew remover (I think it was VicS who suggested Kleeneze) on a test patch of one of the lifejackets and although I always rinse and dry my ljs, I will pay attention to this easily averted fungal attack.
View attachment 47942
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I put "research" in quotes because you don't seem to have done any very basic searching on the subject.

The simple answer is, of course the difference in price is to do with differences in specification, design features and equipment. That is because there are different requirements depending on the expected usage and to a certain extent on legislation (for commercial use) or standards laid down by such bodies such as the RORC, ISAF, and MCA. Just reading the manufacturer's catalogues and publicity material will answer many of your questions, as will reading the International standards you have already been referred to.

There are good accounts of liferafts in use in the MAIB reports highlighting what is good and what is not so good about their deployment. There are regular reviews of developments in liferafts and surveys of what is on the market plus simulated tests of deploying rafts in various magazines. The manufacturers put a lot of effort into developing and improving their product, not least because many of them sell into the commercial market and have to get their products and processes approved by external bodies.

So, would suggest that you do more desk research to find out more about the current designs and construction methods, and where the problems might be. The problems you mention such as flipping, not inflating, poor stability, difficulty in boarding etc are well known - and have been known for years. In many cases there have been specific design changes to improve things - again you will find this type of information in reports and manufacturers literature, but it is inevitable that they are not perfect, just because they are usually operated in extreme conditions by people who have little or no prior experience of using a liferaft.

Very sensible to go and talk to service centres to see what the problems are in the field, but you really need to know more about the subject before you talk to them. Seems your concern is about the bottle and firing mechanism, but not sure this has ever come up as a specific problem in operation. Failure to inflate seems usually to be caused by poor servicing or failure to attach the cord to the pin.

If you look through the history of liferafts over the last 30 years or so, you will find a constant stream of developments and improvements, both in the design and manufacture of rafts. Costs have fallen by around 50-60% in real terms, partly as a result of a massively increased market, but mainly because of improvements in materials and designs that has enabled manufacturers to tailor products to meet a wider market. You can see that simply by comparing the Viking (and other models intended for offshore usage where there is an expectation that survivors may be in the raft for days) and the low cost rafts such as the Seago which are aimed at coastal sailors who are unlikely to go out of range of rescue services. In reality, the number of deployments of rafts in our coastal waters is so small - some years none at all reported, so much of the knowledge about their effectiveness is derived from commercial use (which is often very different from leisure use) or simulation.
 
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