Bosun's chair attachment

Graham_Wright said:
I am in the middle of the usual nonsense from the Boat Show health and safety officer.

He is not a sailing person and has little knowledge of sailing matters.

His latest criticism of our MastaClimba demonstration rig is that the chair is secured to the halyard with a "hand tied knot".

What so others do? Does anyone have a machine that performs the task? I use a fisherman's bend or a doubled up figure of eight.

I used to use a bowline until someone claimed they could vibrate loose (which I believe).

Comments and alternatives welcomed.
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You say that you’re in the middle of the usual nonesense........does that imply that you’ve done it before? If so, how have you previously addressed public liability? Shouldn’t you already have risk assessed the event? What is the H&S officers role? Is he there to offer advice or to give approval? The last thing anyone wants is a nasty incident.

I’ve always been of the view that a knot is stronger than any form of carabiner or shackle.

Has it already gone beyond having an adult conversation with the guy?
 
LittleSister said:
Surely all he needs showing is
a) the breaking strength of the rope; and
b) the % reduction in the strength of the rope for the particular knot you are using?
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Only if the hazard he's trying to address is "the rope breaking due to the reduction in strength caused by the knot", which it almost certainly isn't.

Hence why the OP should politely agree with, and then ignore, the kind of irrelevant observation the chap has made, unless and until an actual potential hazard is specified.

Pete
 
What a response!

The comment "a hand tied knot" was one item in a list of criticisms. Unfortunately, the gentleman concerned cannot enter rational arguments to support his objections. In the past, his general criticism is "it doesn't look safe".

On asking why, he just repeats himself. We provide safety backup far beyond what many yachtsmen use on their own boat. It happens to be the same on my boat as I have halyards sufficient in quantity.

The show requires us to produce risk assessments. These have always been provided and accepted and yet his latest communication denies they have ever been presented. Without risk assessments, we would never have been permitted to exhibit.

I find it almost impossible to reason with the man.

In respect of the original question, it seems most do as we do. I would never use a shackle or any other metal attachment to the chair webbing. I did in the past until I realised the danger of inadvertent dentistry.
 
Graham_Wright said:
What a response!

The comment "a hand tied knot" was one item in a list of criticisms. Unfortunately, the gentleman concerned cannot enter rational arguments to support his objections. In the past, his general criticism is "it doesn't look safe".

On asking why, he just repeats himself. We provide safety backup far beyond what many yachtsmen use on their own boat. It happens to be the same on my boat as I have halyards sufficient in quantity.

The show requires us to produce risk assessments. These have always been provided and accepted and yet his latest communication denies they have ever been presented. Without risk assessments, we would never have been permitted to exhibit.

I find it almost impossible to reason with the man.

In respect of the original question, it seems most do as we do. I would never use a shackle or any other metal attachment to the chair webbing. I did in the past until I realised the danger of inadvertent dentistry.
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So - would Jobsworth accept a shackle?
 
There must be a UK equivalent of OSHA (industrial safety) standards? The answer will be in the standard and it will be cut and dry.

Mr. Michael Lord
Safety Engineer
H.B. Zachry Company
P.O. Box 2534
Victoria, TX 77902

Dear Mr. Lord:

Your September 11 letter to Mr. Glenn Florczak requesting an interpretation of the Occupational Safety and Health Administration (OSHA) requirements addressing fall protection equipment has been referred to the Office of Construction and Maritime Compliance Assistance for reply. I apologize for the delay in responding to your inquiry.

In regard to the use of knots in rope lanyards and rigging used for fall protection, please be advised that knots are not prohibited in lanyards and safety lines used for fall protection. However, OSHA does not recommend their use since they can reduce the effective breaking strength of the line by up to 50 percent. If the fall protection system is designed to accommodate this reduction in strength, knots, such as bowlines, can be used.

Please be advised that Section 1926.251(d)(2)(v) does prohibit the use of knots in lieu of splices in natural and synthetic fiber rope slings used for handling materials.

If we can be of any further assistance, please contact Mr. Roy F. Gurnham or Dale R. Cavanaugh of my staff at (202) 523-8136.

Sincerely,



Patricia K. Clark, Director
Directorate of Compliance Programs
 
During a race, a competitor's spinnaker fell down when a snap shackle was tripped. Afterwards he was preparing to hoist his girlfriend on a spare halyard to retrieve the lost one, using a snap shackle. When I pointed out that this was not a good idea he started to think of alternatives. When I suggested using a knot he thought that was brilliant.
 
Graham_Wright said:
The comment "a hand tied knot" was one item in a list of criticisms. Unfortunately, the gentleman concerned cannot enter rational arguments to support his objections. In the past, his general criticism is "it doesn't look safe".

On asking why, he just repeats himself. We provide safety backup far beyond what many yachtsmen use on their own boat. It happens to be the same on my boat as I have halyards sufficient in quantity.

The show requires us to produce risk assessments. These have always been provided and accepted and yet his latest communication denies they have ever been presented.
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So what exactly is the process here? This isn't a question about what knot is best or anything else technical, so most of the answers here are irrelevant to your actual problem.

What status does this man's "list of criticisms" have? Is it something the organisers require you to address before you may exhibit? Are the items actually formulated in terms capable of being addressed? Who gets to decide whether they have been? Or do you have to satisfy him personally in general and unspecified terms?

The provision or not of risk assessments is surely a non-problem - "The documents you request were provided on <date> and accepted by <person> on <date> as per the email forwarded below. However, for your convenience a second copy is attached to this email."

Pete
 
So do you actually have proof tests of knots in that rope?
If you take it that the knot reduces the strength of the rope by n%, what is the safety factor?
There could be an issue if you are tying the knot in a part of the rope that has been disturbed by splicing the shackle on.

There is a world of difference between being fairly sure something is OK to go up on oneself, and signing it off as OK for other people.
 
I complete RA on a daily basis and also review others as the main part of my day job, this guys role is to make sure you as the supplier / expert have fully assessed and reviewed / mitigated any risks. It you signature that will be on them not his.

If he adds comments he is on a very slippery slope, I know of one main contractors H&S manager who decided to comments and review/ adjust a crane supervisors lift plan and fro foul of the HSE when then just turned up and wanted to know why task was not being done as it would normally. He was very quickly removed from site and no longer does this role.

Just make sure you have done a RA that really does cover the risks not just everything that you see elsewhere and is not relevant, this is always a give away to lack of experience completing RAs. Also make sure you have a detailed Method statement on the task from start to finish, this would detail the fastening method, maybe with some background to why, if you really struggle speak to a local high level access company who do this each and every day, I’m sure they would be happily to help.
 
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Boathook said:
If you used a crewsaver bosuns chair as linked below would crewsaver advise the best way of attaching chair to halyard?
https://crewsaver.com/uk/9326/commercial/rescue-and-safety/493/Crewlift40BosunsChair

There are other company's that do climbing kit who may be able to help.
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FWIW I splashed out on a Harken bosun’s chair. The accompanying instructions are very specific about using the doubled figure 8 and show how to form it. They are also very clear about wearing a harness attached to a separate halyard.
 
prv said:
Only if the hazard he's trying to address is "the rope breaking due to the reduction in strength caused by the knot", which it almost certainly isn't.

Hence why the OP should politely agree with, and then ignore, the kind of irrelevant observation the chap has made, unless and until an actual potential hazard is specified.

Pete
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If he had observed that "the knot reduces the strength of the rope" I could have answered that. (The breaking strain of the particular rope is 3.4 tonnes when new. It is renewed each year. However, if it did break (or possibly more likely , the chair webbing failed,) safety would be ensured by the two back up provisions we employ).

I can cope with "what ifs"; I cannot cope with "It doesn't look safe" with no explanation.
 
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Zing said:
I use a single figure of eight. Why might a double be preferred?
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As no one answered I looked into this myself. It seems the knots are a similar strength. The double is easier to undo if loaded. The single is easier to remember how to knot. I have used the single a lot and have no problem undoing it, so for me it wins. Happy to be corrected if I missed something.
 
Double is just as easy as you follow the original figure of 8. It is a better knot in that the friction of both lines means it cannot slip. The only potential problem (but common with any knot) would be chafe through the bight going through the loop on the chair
 
Zing said:
As no one answered I looked into this myself. It seems the knots are a similar strength. The double is easier to undo if loaded. The single is easier to remember how to knot. I have used the single a lot and have no problem undoing it, so for me it wins. Happy to be corrected if I missed something.
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You need to read it again. A single and double Fig 8 are completely different knots with completely different uses. You can't substitute one with another.

A single Fig 8 is a stopper knot you can put on the end of the sheets to stop them running through a fairlead.

A double Fig 8 forms a loop, either by tying it double or tying a single and following through to double it up if being tied into a sealed eye or ring.

The Fig 8 is a versatile knot that can be satisfactory in a variety of situations. In climbing it is taught to beginners and used a lot by youth groups, etc, because it is a "one knot does all". Also if you tie it wrong there's a good chance it will end up as an overhand knot, which sort of works as well.

But like a lot of jack of all trades, it's not really the best knot in any situation - in particular, it's hard to adjust and jambs badly when you fall, so most experienced climbers use a bowline and either tie off the loose end with a stopper knot or use a self locking variant such as the Yosemite Bowline. Similarly, if you want a loop in the mid portion of a rope, the Alpine Butterfly is better, a clove hitch is more adjustable when tying into a belay, the double fisherman is best for joining (permanently) two ends of a rope to form a loop and the overhand knot is best for joining two ropes temporarily for an abseil.
 
Motor_Sailor said:
A single Fig 8 is a stopper knot you can put on the end of the sheets to stop them running through a fairlead.

A double Fig 8 forms a loop, either by tying it double or tying a single and following through to double it up if being tied into a sealed eye or ring.
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Are you sure?

I thought a "double figure 8" ended up with two loops (https://en.wikipedia.org/wiki/Double_figure-eight_loop, https://www.youtube.com/watch?v=o8tZvJaCQ9Y )

The figure 8 loop (sometimes aka "rethreaded figure 8") is what you describe as a "double figure 8" only forms a single loop and is often used as you describe.
 
Graham_Wright said:
If he had observed that "the knot reduces the strength of the rope" I could have answered that.
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Exactly, that's the point I'm making. He hasn't actually proposed any hazards, so there's nothing for you to respond to.

Hence why I'm trying to tease out what the process is that you're working under. Are you actually blocked from moving forwards, and if so, what precisely do you need to do to remove that block?

Pete
 
Sea_Spray said:
Are you sure?

I thought a "double figure 8" ended up with two loops (https://en.wikipedia.org/wiki/Double_figure-eight_loop, https://www.youtube.com/watch?v=o8tZvJaCQ9Y )

The figure 8 loop (sometimes aka "rethreaded figure 8") is what you describe as a "double figure 8" only forms a single loop and is often used as you describe.
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Correct. When I said I used a figure 8 I was using the rethreaded figure 8 as I thought that it was correct to just call it a figure 8. The double figure 8 is a different thing as you say.
 
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