Technical News

At the AGM held in December 2006, further changes were made to the class rule describing the arrangement of the throat halyard for the mainsail.  The changes adopted a year earlier had not been easy to implement in practice.

Accordingly trials were conducted on boats from different clubs during 2006.  The intention was to allow a greater purchase to assist crews to adjust the halyard and also to permit a jam cleat to make adjustments easier.

The amended rule reads:

Rule 3. Throat Halyard: Not less than 4mm diam. galvanised or stainless steel flexible wire rope and not less than 8mm polyester or similar rope downhaul arranged with a purchase.   As an option the rope downhaul may be augmented with a separate block and tackle capable of adjustment whilst sailing.   One end of any such block and tackle shall be affixed to the tabernacle and the other end to the lower block on the rope downhaul provided that in any event the rope downhaul and (if fitted) secondary block and tackle shall not be arranged so as to apply an overall mechanical advantage exceeding 8:1

 

Some owners will be happy to leave their halyard as originally rigged with a simple 3:1 purchase.

Whilst the revised rule allows many different arrangements of halyard (as long as the overall purchase does not exceed 8:1), the system shown here has been demonstrated to work effectively.

Some of the physics gets complicated in working out the mechanical advantage, so by adopting a similar system owners will stand a better chance of remaining in class.  Remember – this is a one-design class and only specifically permitted variations are allowed.

The only new bits needed are a double block with becket, a triple block with jam cleat and about 3 to 4 metres of rope.  These should be available from your local chandler, or from the class sailmaker.