In 2002/2003, we worked very closely wih Jim Hunt and North Sails to optimise the best
sail/rig package in anticipation of the class rule change to carbon masts. The principal
of our design was to take the basic 'bend shape' both the Finn and Europe masts were
producing to win the 2000 Olympics (with Ben Ainslie and Shirley Robertson) and apply
to the righting moment of the OK. This would give us a the correct rig stiffness for
the OK load and the best bend shape for sail performance. Chimp Hobson and North Sails
used all their knowledge and expertise of making the Gold medal winning sails and
produced an OK sail to fit this 'bend shape'.
The biggest difference we identified over the alloy masts was the dramatic increase in stiffness sideways through the deck area. It was felt that reducing the immediate sideways 'hinging' of the old alloy mast at deck was a fast way to go (keeping the lower/mid leech of the mainsail closer to the centre line of the boat).
We made approx 4 iterations of the mast (if you don't count sanding the first mast to
increase the bend fore and aft!!), and a final laminate specification was decided. As
the masts are CNC filament wound, we also had the re-assurance that each mast we produce
is identical as we can take the human laminating process out of the production equation.
The masts were then thoroughly tested by Jim Hunt and Nick Craig and used to great success to finished 1st and 2nd at the World Championships in 2004.
In 2005, we have made some improvements to the mast in strengthening them further around the deck and boom bracket area and producing the masts within 0.6kg of minimum Class rule weight to allow sailors to 'tweak' the final corrector weight position to gain the perfect tip weight measurement.
As 95% of the masts we produce at Selden are 'stayed' masts, this was a fantastic design project to be involved in and we are extremely proud of the success the mast has had.
Ian "Chips" Howarth