Half a croissant, on a plate, with a sign in front of it saying '50c'
h a l f b a k e r y
The embarrassing drunkard uncle of invention.

idea: add, search, annotate, link, view, overview, recent, by name, random

meta: news, help, about, links, report a problem

account: browse anonymously, or get an account and write.

user:
pass:
register,


                           

Sheet Torque

How to be gentle without trying
  (+8, -2)
(+8, -2)
  [vote for,
against]

Jim watched a few America's cup races where rigging failed under sudden heavy load (from a wind gust).

He decides to protect his boom from these loads by limiting the torque that can be applied to the sheet using the same mechanism found in a torque wrench.

Under heavy loads the sheet will be released and can only be tightened when the load on the main sail drops.

Sigh.

madness, Nov 27 2006

[link]






       The modification will also protect the mast from main sail loads ---- and a similar modification to the jib will protect (the mast) from jib loading.   

       Not alot to be done about spinnaker loads...
madness, Nov 27 2006
  

       DAMN IT! I thought this was going to be an idea that kept my FKING sheets on my bed once and for all!
Chefboyrbored, Nov 27 2006
  

       Jim Torques - isn't he that cutting edge new poet?
DrCurry, Nov 28 2006
  

       Hmmm not been fishing for a while but yes --- a bit like landing a marlin on a fly...
madness, Nov 29 2006
  

       [formerly-marked-for-deletion] disguised complaint rather then invention
jmvw, Nov 29 2006
  

       Looks like an invention to me.
ldischler, Nov 29 2006
  

       I'm going to vote for it, though only because I'm sure there aren't many really new ideas in sailing these days. Not since, you know, Phillip II or thereabouts.
shapu, Nov 29 2006
  

       will it just release until back within the load tolerance 'zone' or just totally release?
oneoffdave, Nov 30 2006
  

       until the load drops back --- you can just about see the grinders working hopelessly in heavy winds to bring the sail back into trim...
madness, Dec 01 2006
  

       Technical Nitpick,   

       The force experienced by a line on a sailboat is not torque. The correct force is Tension. If one assumes that you are using a winch then a torque force would be generated on the winch housing by the sheet which could then be controlled in the way you describe.   

       From a purely sailing point of view I doubt you would see anything like this on a serious boat even if it were available. Releasing the sail and then stopping it again will very likely produce an even larger force in the rigging than the wind alone. Also keep in mind that many times a failure occurs due to fatigue or a flaw, Sometimes a gust of wind causes it others a shift in the wind, sometimes it is just in a very specific orientation, I've even seen situations where wave action causes the boat to rock severely inducing failure. When you are pushing a piece of equipment to its absolute limit things will break, its part of the game. You've way oversimplified the situation you are trying to address.
jhomrighaus, Dec 01 2006
  

       Well, yes you are correct --- I just prefer sheet talk to sheet tension...   

       I will point out that it is not be possible to enduce tension on the sheet greater than corresponding torque at the winch --- even if you "let it go and catch it again"...   

       From a sailing perspective the maximum tension on the sheet will place a limit on the best heading the boat can acheive in different wind conditions. I guess if that sort of mechnical override is abhorent then a torque gauge might be better...
madness, Dec 18 2006
  

       //I will point out that it is not be possible to enduce tension on the sheet greater than corresponding torque at the winch --- even if you "let it go and catch it again"... //   

       The inertia and friction in the tackle and in the winch will allow much greater forces to be applied for short periods of time. Add a free swinging sail and boom to the mix and you could snap lines and sails before the system can respond(this happens all the time with fishing gear which utilizes this type of system)
jhomrighaus, Dec 18 2006
  

       With the right design and settings, this would be of benefit. It might take time to get the sail back in again, but that has to be balanced against losing the sail completely.   

       Where there is an issue to be addressed is in setting the limits correctly; it's not straightforward. The difficulty lies in the fact that the strength of the rigging is variable, due to manufacturing tolerances and deterioration in use. This system would set an artificial limit, lower than the ultimate strength of the structure. Consequently there would be a loss in performance in on-the-limit conditions. It would be a challenge to tweak and tune this system so that the sail would release almost at the point at which it would fail. [+] due to the demonstrable potential, even if realisation of the potential would be difficult - is that not part of what the bakery is about?
david_scothern, Dec 18 2006
  
      
[annotate]
  


 

back: main index

business  computer  culture  fashion  food  halfbakery  home  other  product  public  science  sport  vehicle