Further Development - A Sailmakers View
A Sailmakers View
by Robert Atkins of Tru Flo Sails
(Flying 11 Journal 96/97)
1996 saw the return of the Australian and State Titles to the Manly 16' Skiff Sailing Club. Below I will set out the main reasons behind this success.
The next step was the mast itself. After watching what was the norm, I felt that the tips of the mast were too stiff and not giving the boat the gust response I was looking for. With the tips being stiff, this was also creating overbend in the bottom section. Along with Julian Golding from Spunspar, we got together all the current masts that were being used. We set about doing all the relevant bend tests and although they had similar characteristics, I still felt we could do better.
Along came the S-8000 with the oval tip. This mast, when tested gave us a softer fore and aft bend in the tip, without placing unnecessary loads on the bottom section. The sideways bend in the tip was reduced, giving much better control of the mainsail leech twist. The next gain with the spar was the bottom section being straighter, the forestay tension could be controlled, minimising the amount of layoff in the jib luff itself.
Once we put the package together the next thing was the mast rake, rig tension and spreader lengths. During my first year at Manly, we worked on various spreader lengths, from 20 mm to 50 mm out of line and neutral to 20 mm of forward poke.
For the lighter crew weights, I settled on spreaders placed in a neutral fore and aft position and 25 mm out of line. For the heavier crews the fore and aft position was pushed forward 20 mm at the tip. Mast rake and rig tensions were recorded along the way, and particularly with the O'Mahony boats, we were able to crank the rig tension up a lot tighter without any fear of damage to the hull itself.
Peter Moor made the blades for Ben Bianco's boat - lighter and stiffer than usual, they are also very true in sectional shape with straighter trailing edges. The stiffer centreboard helps to gain maximum height to windward and reduces the amount of sideways slide that softer centreboards create.
The boat itself was set up with minimal adjustments. I feel that if the set up is simple, the chances of falling into the trap of 'adjust this, adjust that', that the crew end up forgetting about sailing the boat. The jib has one adjustment on the sheeting, which is the inboard and outboard positions, and the luff tension adjustments. The mainsail has luff tension and boom vang and obviously mainsheet tension. The biggest problem I've seen is that most of the guys tend to crank the vang on too hard, and spend the day fighting the boat, staggering around the course.
The sails themselves, were quite different. The headsails are quite full with the mid leech very tight, so that the sheet can be eased to open the slot without the leech bending out. Because of the way the mast is rigged, and also the mast itself, we were able to build a flatter mainsail, that doesn't stall in lighter air and also maintains the leech low down in fresher breeze, which is paramount to maintaining good height to windward and also maintains more even pressure in the boat through the breeze fluctuations.
I'd like to thank all those who assisted me over the last couple of years. Julian O'Mahony, Julian Golding, Peter Moor and Glenn Bianco for their tireless efforts in trying to improve the boats and a special mention to Mark Pryke for his assistance with the Manly kids on the sailing rules.
I trust that some of these ideas can help you all to improve your performances on the water.
Good luck and good sailing!