The J/109 Class Association Forum

The Technical Committee is proposing the following amendment to the class rule:

4.3.17 The maximum power ratio of the jib lead adjusters will be increased to 8:1


Background: to get the full advantage of the recently approved in hauling rule, it would be beneficial to increase the power ratio of the jib car adjusters to allow adjustments in medium/heavy air.
JBoats have indicated that if the J109 were designed recently it would be specified with a 6:1 adjustment and in haulers
A very simple change to the existing class legal 4:1 adjusters is to add a 2:1 cascade between the forward turning block mounted on the track and the existing cleat, creating a 8:1 adjustment (not suitable for overlapping jibs).
The TC suggests this amendment is fast tracked for a vote before next season starts, implementation by April 1 if approved.

The following drawing added to show existing class legal system

I have gotten a few requests to explain/show how the standard 4:1 plus a 2:1 cascade could work. I rigged a temporary system on Zig Zag today. The distance from the forward turning block on the track back to the termination point at the back end of the track is 122" giving us a maximum travel of the jib car of 30 1/2". in our case that is +/- 15" around the base position for the class jib. These dimensions will vary somewhat boat to boat.

From the Class Secretary:

Preamble:
The proposed rule change was brought by the Technical Committee to the Executive Board for review and comment. The Executive Board approved proceeding to vote the following, with Executive Board comments incorporated.

Background:
To get the full advantage of the recently approved in hauling rule, it would be beneficial to increase the power ratio of the jib car adjusters to allow adjustments in medium/heavy air. JBoats have indicated that if the J109 were designed recently it would be specified with a 6:1 adjustment and with in haulers. As an example, a very simple change to the existing class legal 4:1 adjusters is to add a 2:1 cascade between the forward turning block mounted on the track and the existing cleat, creating a 8:1 adjustment (not suitable for overlapping jibs). The system is not permitted to be operated or rigged to the windward side. More information and pictures are available on the Class Forum.

New Proposed Rule:
4.3.17 The maximum power ratio of the jib lead adjusters permitted is 8:1. This can be done by adding sheaves to existing tackle or, adding a 2:1 cascade to the existing 4:1 tackle. The jib lead adjustment line must use the existing cheek block and jib lead cleat on the same side as the jib car it adjusts.

A ballot will be prepared shortly and sent to all members.

Respectfully,
David Rosow
Secretary

From the Class Secretary:

The proposed rule 4.3.17 regarding the jib lead adjusters received more than the two-thirds votes necessary to be adopted. The new rule becomes effective on March 1, 2017. The updated class rules will be posted on the website shortly.

Respectfully,
David Rosow
Secretary

Is it possible to upgrade the car and sheeves on the track to get the additional purchase? Has anyone shared the part number in another post?

Thank you
Dan