DN NA Class

 (see picture below)
???

Not trying to stir the pot but, has there been a ruling from the DN Technical Committee on this design? If not, when can the class expect a ruling on this subject?



Respectfully,

Mark Isabell



 

The chock issue has been discussed thoroughly by the TC and the committee is voting the weekend of December 16-17, 2006.    Members will be advised shortly.

This has been a technically challenging interpretation for the Technical Committee (TC).   After long discussion and review of the design, the TC voted and has come to the majority opinion:

The "Kent" style chock (with a narrow outer flange) and a runner stiffener with the pivot bolt passing through it meets the current Specifications. 

The reinforcing bar between the head of the pivot bolt and the runner body is considered a runner stiffener, and as such must meet all specifications for a runner stiffener.  Being a runner stiffener, it is not considered part of the runner plank hardware and is not included in the measurement of plank length (spec B.1).

The Technical Committee is working on the wording for the Official Interpretation.

Paul Goodwin
Chairman - IDNIYRA Technical Committee
email: webmaster@idniyra.org

edited 21 Dec 2006 by Paul Goodwin

Jeff Kent, the innovator and sailor of the bamboo mast, developed these chocks.  The inside flange is stiff and full length.  The outside flange is very narrow, only an inch or less wide.  The runner bolt also clamps a carbon fiber "reinforcement" to the runner and bolt tension pulls the whole assembly together.

Advantage:  The reinforcement clamps the runner into the full length half of the flange.  TO align the runners, shim only the side against the inside of the flange.  More predictible and easier.  Also, your chocks will NEVER be bent... The runners are mostly supported at the fore and aft ends of the flange.  Aschocks get bent in use, most of the support is in the middle of teh runner.  Makes for a stiffer system overall.

Disadvantages:  TBD.  THe retention of the runner depends on the bolt.  It IS a strong bolt....

Here's a link to another picture of the chock.

http://www.iceboating.net/node/102

Can the chock be sailed without the carbon fiber "reinforcement" ?

I'd ask Jeff Kent... 

In theory, it should be fine, but why would you do that?    Light air and snow???  All the parts work together to achieve the design intent.

Ken

I guess I'll ask the question before someone shows up on the ice with it.  Can this same stiffening element be used on the inside of the chock?  "The way I read the interpretation it can."  This essentially allows a sailor to add a stiffening flange to the chock on the inside and outside and by-pass I.5c the max. length (9") of a side chock.  Nothing stops this runner stiffener from being on both sides of the chock and up to 36" long x 3" wide.  Thinking about this more I assume any change to this stiffening flange during a regatta would also require a new runners sticker be applied, since its considered a part of the runner.

Sounds like this will surely be a topic of discussion this year at the annual meeting.

You can't use "the same stiffening element" on the inside of the chock since it would require modification to the inside flange and the chock would no longer meet all of the Specifications.  Adding a stiffening flange to the inside of the chock is allowed, but it can't be longer than 9".

However, there is no reason the runner stiffener(s) can't be 36" long and 3" wide, as long as all of the requirements in the Specifications and Interpretations are met.

You are correct about changing stiffeners during a regatta.  "However, when the stiffening element is changed, the runner is then counted as a new runner in total count of the nine runners allowed." [Interpretation E.Runners 7/1/92]

I have just returned from Jeff's shop. Wait till you see the new bamboo stiffners for his chocks