I need to replace my puller:
Fairly certain mine is 4mm, which appears to be the Winder standard.
Thanks, Is that D12 or V12 ?
It's grey which, by the looks of the Marlow site, makes it 'V'.
Looking at the pictures of Tom Stewart's boat in the 'rigging guide', it looks like he has used 3mm V12. The thinner stuff has a SWL(?) of about a tonne so should be fine. Think of the windage you could save !!
Safe Working Load?
I suppose I should have said 'breaking strain'! Happy now?
3mm Vectran or Dyneema.
Oops, I took the question mark after SWL as an invitation to explain the abreviation. To be really picky SWL is quite different to breaking strain.
SWL = Safe Working Load
and of course breaking strain and SWL are totaly different: one is a load (mass or force) and proportion of tensile strength, the other is how far it stretches before it breaks.
There was a time when you could just post a question on a forum and get an answer, though not on this one, where you can fortunately rely on the initial question being subverted into a discussion of Danish phrases, engineering terms or what happened in the class in the 1950's
Perhaps I should have refered to TPAWIRIMGP, then everybody would have realised what I was talking about. Oh, sorry! You don't know how to define TPAWIRIMGP? Silly me; it's 'The Point At Which, I Reckon, It Might Go Ping'.
To give a sensible answer, 3mm Vectran or Dyneema is fine, the plaited variety BUT after a certain amount of time the UV will cause degradation and that will weaken it as will the chafing of the jib sheets and eventually it will reach pinging point, inevitably as you power up the kite on a tight and windy reach. The bang as it goes is quite impressive, we thought we must have lost the mast but as it is a venerable Superspar from the 1st batch of carbon technology it is fortunately pretty bulletproof. I have resolved to replace annually since.
Thanks for the clarification on the 'technical' terms. I had been told by my wife that safe working load was the amount of shopping I can bring in from the car in one trip, and that breaking strain is the point our relationship will reach when I want to go sailing all weekend. I can confirm that this is often the point at which it might also go ping, so thanks to Alistair for the confirmation on this point.
Interestingly Dyneema is stronger than the equivalent sized vectran!!
If the puller goes ping, what goes pong and how soon after the ping will the pong follow.
If ze co-efficient of ping iz multiplied by ze square on ze hypoteneuse of ze pong elemental retardational constant, zen we have ze ping:pong ratio.
You don want the pull to be stronger that the breaking point of the desk pully pulling up the deck, do you? Whats more expensive - deck? Mast?
should have said - deck? deck & mast?
The force on the deck sheave will be horizontal and it's difficult to break the deck in that plane, the mast will go first in a wipeout particularly one of those fragile expensive Chipstow twigs. Another 3 bust at Ranelagh I see. Just as well I have had my insurance premium demand for this year!
Andrew, you're raising an interesting issue for the class here: what is the breaking point of an insurance company?Or rather how many claims will it take before insurance companies place restrictions on our sailing because of repeated claims?
I wonder if people overload their mast in strong winds. Leeward shroud just tight is a lot of tension in 35mph of wind!
Has anybody done any analysis of mast breakages? Point of breakage? Age of mast? Hit the bottom? etc. Every time it blows much more than a F4 there seems to be a report of a broken mast.
I think all of the ones broken at Whitstable hit the bottom. At salcobme it was very gusty, wind hits boat, boat nosedives and the wind pretty much blows the rig off the boat. I'd imaibne Ranelagh was similar.
All 3 at Ranelagh hit the bottom - capsize + wind over tide + shallow + sticky clay on river bed = goodbye mast!
The latest slant on this thread is an interesting one, but I would be surprised if breakages were significantly higher now than they were when the M1 was the twig of choice - they seemed to collapse with regularity. I would also be surprised if Merlins were picked out by the insurers for special treatment; I was ARO at the the Tide Ride this year, and was around for the 200/400 meeting at HISC, and on both occasions there were many masts reverting into kit form - both Ali and carbon - with ne'er a Merlin in sight...
I think it's just unfortunate that the two major events in the class have had a lot of breakages this year. At salcombe this was due to the extreme nature of the wind and at Whitstable due to a windy day and being a relatively shallow venue. At Looe last year how many masts broke?
I don't think it is true to say that all the mast at Whitstable broke because they hit the bottom.
I do, I was there.
I have had 2 masts break in 14 years one hit the bottom at Chichester and the top bit is still there along with the top panel of the mainsail, the other was when a shroud broke at Ranelagh. Both were alloy. I wouldn't mind breaking a mast to replace with a more modern alternative but I can't seem to do it.
And given Andrew's track record with carbon tiller extensions that's really quite remarkable......sorry Andrew, couldn't resist :)
I was there at Whitstable, as well and definately half the mast that broke were gear failure.
OK Dave, but I haven't broken another one since that memorable day!! Now have on Tony Blackmore's recommendation a big thick carbon thing that has resisted me falling on it admirably. Maybe if I fell on the mast in a capsize?
Interesting fact, A 49er belonging to a un-named relative of mine, with a ally bottom mast and carbon top mast, had a bit of an accident this summer. The ally mast section broke, the ally spreaders broke, the carbon bits were all fine. By the way, the bill for repairs were probably 3 times the cost of a similar style crunch up on a merlin, (the insurance is about twice and so is the excess)
Interested in the points about gear breaking and specifying rope diameters for the puller.
The main force on the puller is opposing the push from the spinny pole and Newton therefore suggests about the same as the tension in the guy. Powered up on a tight reach that is likely to be up to 150Kg do we think, about twice what I can pull in a straight 2-armed yank on it. But if the mast has actually gone out of column and begun to invert there could be on occasion another 50Kg max to pull it back into line, certainly won't be much more. Who here has actually broken a puller that was not old and a bit frayed, and how?
I once pulled something that was broken, old and frayed...does that count?
This is a link a the Speeds web site that has a description of the Holt Pro Line 3mm, which would be ideal for a puller.