Is it worth looking at Downwind speed? The fastest mast at the Finn Masters Worlds….
During the development of the new Ceilidh Finn Mast a wide range of design choices were considered. When revisiting PieterJan Postma’s mast design the developments previously done in 2018 were optimised to give a quite unusual set of bend numbers.
In the bend test, PJ’s mast for 2025 has very similar characteristics to the mast first used back in 2018. With a new mast profile shape, the laminate has been modified to give a better dynamic response upwind.
As Finn masts have usually been designed to manage the upwind power in the boat, a lot of emphasis is placed on the upper side bend and the torsional stiffness of the profile. Unfortunately, this has to be balanced against the downwind performance. The Ceilidh design considers the downwind performance equally important to upwind performance, resulting in a slight compromise upwind. As the Finn is very responsive to sailing deep downwind with speed increases on the up-turn it would be logical that the leech tension and shape needs to be more constant. Having spent a number of hours on the water and reviewing videos it became clear that there were possibilities for improvement in the downwind response of the mast.
It appears that with the assumption that the total mast bend (read a bend at 20° from the fore-aft axis) determines how the leech works, it is possible to accurately replicate the dynamics of a ‘standard’ mast. This, unsurprisingly, makes the mast far less ‘tough’ to sail than one would expect from the curves.
This allows PJ to sail with the following bend numbers:
fore-aft 0 83 113 83 0 tip 535
side 0 67 102 91 0 tip 340
Percentage wise the side values are 66% at the 1/4 height, which is an increase of 2% relative stiffness while the 3/4 height is at 89%. Recent top-of-the-fleet masts have had percentages of 63% and 91% – 92%. Tightening up the 3/4 height value, or better said slightly softening the 1/2 value relative to the rest of the mast gives the leech control that is required.
Ceilidh Composite Technologies with a team of 7 staff has been building carbon dinghy masts since 1997. With more than 1200 Finn masts as manufacturer of the HIT mast, 1250 Europe masts (Olympic Gold in 2004), 850 OK Dinghy masts, and a wide range of custom dinghy masts for classes such as the Flying Dutchman, Merlin Rocket, Phantom and Contender the company focuses on ‘products that perform’.
Less frillls, nothing too fancy, but high tech performance masts with smart production processes.
For more info visit www.carbonmasts.com or contact Thomas by email at finn@carbonmasts.com