Mast climbing: Will 8mm rope REALLY take my weight?

[Bav34]

I have just bought a 'mast ladder' see here and was thinking through the safest way to climb the mast when I have my able assistant with me.

I like the idea of hoisting the ladder on my 8mm topping lift and having either a back up harness or bosuns chair, attached to the main halyard, being pulled up with me as I climb.

The idea of using the topping lift didn't occur to me until I looked here where even 3 strand Polypropylene shows a breaking strain of 960 kilos!!!

Or 12 of me!!!

My topping lift looks like Cruising Dyneema = 2500 kgs! Good grief.

I'm worried whether 8mm is enough for one, looks like it will support a football team!

Wotcha think?

 

[sailorman]

I have just bought a 'mast ladder' see here and was thinking through the safest way to climb the mast when I have my able assistant with me.

I like the idea of hoisting the ladder on my 8mm topping lift and having either a back up harness or bosuns chair, attached to the main halyard, being pulled up with me as I climb.

The idea of using the topping lift didn't occur to me until I looked here where even 3 strand Polypropylene shows a breaking strain of 960 kilos!!!

Or 12 of me!!!

My topping lift looks like Cruising Dyneema = 2500 kgs! Good grief.

I'm worried whether 8mm is enough for one, looks like it will support a football team!

Wotcha think?

to be safe haul-up swmbo first

 

[Bav34]

to be safe haul-up swmbo first

But she is just sooooo petite it wouldn't be much of a test.

(Incoming Brownie points !!!!)

 

[sigmasailor]

Never trust a single line; always make sure you use a back-up line.

8 mm line can be strong enough; a lot depends on the type of line used (steel, dyneema, polyester, nylon?) and the quality of the line (UV, chafe). I wouldn't be surprised if the even the weakest line would have a 10 fold safety margin

 

[fireball]

If it is Dynema then it should be ok - if not it may just stretch a bit ...

Always test at deck level first ... but yes - 8mm should hold you - I hoist a 10mm line up for my climbing kit...

 

[wizard]

I have just bought a 'mast ladder' see here and was thinking through the safest way to climb the mast when I have my able assistant with me.

I like the idea of hoisting the ladder on my 8mm topping lift and having either a back up harness or bosuns chair, attached to the main halyard, being pulled up with me as I climb.

The idea of using the topping lift didn't occur to me until I looked here where even 3 strand Polypropylene shows a breaking strain of 960 kilos!!!

Or 12 of me!!!

I'm worried whether 8mm is enough for one, looks like it will support a football team!

Wotcha think?

Your method is exactly the way I use my mast ladder so should be fine

 

[dunedin]

The new rope strength looks fine - but the other factors include:
- strength loss through knots or splicing - much less than the rope strength
- any damage (eg chafe at the blocks)
- UV damage - how long has the topping lift been in the sun ?

As others have said, also use two ropes and don't use external halyards as primary rope in case the block or tackle fails

It is UV that would worry me most. I was up the lower mast on a stout 10mm halyard one day (with topping lift as backup). Next day the outer cover of the halyard parted through UV failure - though the inner strength bearing core held. Was a bit spooky though. (Have sent others up instead of me since ;-)

 

[LittleSister]

Note also that the line may have to hold something greater than your weight. If you slipped, say, and started to fall; or were being lowered jerkily; the tension on the line arresting you would be greater than just your weight.

 

[Bav34]

Note also that the line may have to hold something greater than your weight. If you slipped, say, and started to fall; or were being lowered jerkily; the tension on the line arresting you would be greater than just your weight.

Thanks for the other replies ... all noted but THIS post is why I don't want to use the (stronger) halyard and rely on the (weaker) topping lift to catch me should I slip.

 

[savageseadog]

10mm is probably as low as you should go, you would want to be sure there are no major abrasions and less than about 5 years old. 8mm Dyneema would be strong enough but it would be very poor as a safety line as it has little stretch so the load on you and the rope would be high in the event of a shock load. I would suggest pulling a stronger and/or newer line through for the job if needed. UV might be overstated as a problem as the strength is really in the protected core.

 

[Kurrawong_Kid]

I have a the same mast ladder as yours. Highly recommended. I haul it up on a spare main halyard in the trisail groove (in-mast furling), bowse it down with a tackle and have SWMBO take up the slack on a bosuns chair with the spinnaker halyard as I positively climb at a step every 10 sec. until I'm kna****d and well out of breath and have to take a rest!
Attended a talk a few months back from a rigger who said that there is now no reason, except tradition and appearances to have steel standing rigging. Dyneema apparently lighter, stronger and less likely to part with no warning.

 

[bbg]

The only masthead halyards I have are 8 mm (when covered) dyneema, and I have no hesitation in trusting those.

 

[jimi]

I go climbing and use 8mm ropes so that should be ample. However as others have said make sure you have a backup safety system as it unlikely to be the rope that will be the point of failure in the system

 

[Baggywrinkle]

I agree, always use two lines .... it's more likely to slip or accidentally release than break - even with the outer UV damaged, the inner should easily hold you.

With a breaking strain of 2500 Kg, that means a force due to gravity of 24,500 Newtons is required before the rope breaks.

For your 80kg to exert a force of 24,500 Newtons on the rope you would need an average deceleration of -306.25 m/s^2. (F=ma).

Assuming the rope takes 0,2 secs to stretch and snap, with your final velocity equal to zero, you would need to be travelling at at least 61,25 m/s (220 Km/h) before the rope would break trying to stop you. a=(v2-v1)/t

This is considerably higher than the terminal velocity of a human body in the atmosphere. So you're ok.

(hope I got the maths right ... )

 

[Iain C]

The rope is likely to be the strongest link in the chain (unless very UV'd or chafed).

Examine every winch, shackle, turning block etc...do you know what the block is like up the top that you will be dangling off? Are all the split pins in etc?

Last time my crew tried to hoik me up the rig, the tufnol winch cracked where the handle went in. Exciting!

And lastly, tie your own bowline (or suitable climbing knot) to your chair, dont use the snap shackle (although putting that on after your bowline can't hurt)

Oh, one more thing, don't do what I did and nearly drill through your own halyard whilst fitting wind instruments onto the masthead!!!

 

[Judders]

Without wanting to sound condescending, if you need to ask the question, you probably need some more hands on guidance.

 

[Twister_Ken]

Bought a reel of light line (2 or 3 mm. Flag halyard stuff) to use for mousing halyards. It carried a label with a SWL of 100kg, a little less than my weight. For fun, I hauled a length up the mast, cleated it off, tied a bowline a couple of feet above the deck, and stepped into it, like a stirrup. It stretched almost down to deck level, but it held my weight.

8mm: piece of cake.

 

[bendyone]

Depends on how the topping lift block is fixed to the top of the mast. On my last boat - Hunter 26 - it was only a fairly small block and shackle fixed to the back edge of the mast cap casting. Not as strong as the main which went through a sleeve roller and down inside the mast.

 

[savageseadog]

Without wanting to sound condescending, if you need to ask the question, you probably need some more hands on guidance.

I agree with that but I've got fed up of saying it and the negative reaction that comes. I keep telling people not to use powered winches for mast climbing to be basically called a fool.

 

[Iain C]

I keep telling people not to use powered winches for mast climbing to be basically called a fool.

Really? That really is a huge no-no!!!!