National 12

General Boards => General National 12 chat => Topic started by: iampete on 24 Jun 2014, 04:26

Title: Temple Vang Legal or Illegal?
Post by: iampete on 24 Jun 2014, 04:26
A Temple Vang is an alternative kicker arrangement, a lever is attached to the boom at the gooseneck end at 90ish degrees and is pulled towards the mast under the boom, see attached pictures.
This has the advantage of freeing up space for the crew and reducing kicker loading.
However i'm not sure if it would be legal under the rules. 
As far as I can tell there a two rules that concern booms :


As I see it making a L shape boom (like the first picture) that could all pass through a 102mm diameter ring would be prohibited as a  "permantly bent boom".
However a revovable leaver arm could be used as in the second picture, or would this be prohibited as a "Jumper Strut"?
A few 12's have gnavs i can't see how they can be allowed and temple vangs not, just want to make sure before I breack out the epoxy  
 
Peter
Title: Re: Temple Vang Legal or Illegal?
Post by: smilie on 24 Jun 2014, 08:09
It shouldn't be, to my mind it's not permanently bent and there is no mention that boom or ring can't move so that boom can pass throught the ring. 
I think rule 9.3 is there to stop people from making large diameter booms which a temple vang clearly isn't.
Title: Re: Temple Vang Legal or Illegal?
Post by: STU W on 24 Jun 2014, 11:08
Surely you could bolt on the lever arm or have it sleeved along the boom and pinned in place so it is not a fixed part of the boom and is just a boat fitting. Can't see anything illegal then
Title: Re: Temple Vang Legal or Illegal?
Post by: JohnMurrell on 25 Jun 2014, 08:24
I don't believe that it conforms to the class rules; the whole boom including fixed fittings shall pass through a 102mm dia circle which clearly this one wouldn't.
Title: Re: Temple Vang Legal or Illegal?
Post by: Kevin on 25 Jun 2014, 05:04
The first arrangement pictured does not appear to be capable of passing through a 102mm circle so would be out of class.
The second picture might pass this test but I can't see it would save much (if any) room in the boat because of where the rope/wire from the strut goes around the boom and I would be seriously concerned about point/crush loads from it on a carbon boom, and also have the same concern about the mast.
Kevin
Title: Re: Temple Vang Legal or Illegal?
Post by: iampete on 25 Jun 2014, 09:49
Having thought about it further, I think having a one piece L shape boom that could all pass through the 102mm circle would put so much stress at the angle joint it would be tricky to get right, As STU W suggest a Lever arm that is sleeved over the boom and then pinned or bolted in place is the way to go. I guees the problem then lies with the Fixed fittings rule. My boom wouldn't pass through the circle with the main sheet blocks attached, I would have to get a pair of plyers to remove them. I'm my opinion bolts, pins and screws would be removable but rivits and glue not.
Kevin, you would need a boom designed for the extra load, the load on the mast however would be more or less the same as a standard kicker.
Peter
Title: Re: Temple Vang Legal or Illegal?
Post by: smilie on 26 Jun 2014, 08:09
I'm just wondering what rule 9.3 is written to prevent? Is it worth considering a re-write of the rule so people can experiment with different kickers systems?