Ken Smith
ADMIN
Posts: 289
sail often, travel light
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« Reply #2 on: March 08, 2007, 06:16:35 PM » |
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Paul:
I certainly agree with the theory. However, in several high-wind scratch races, more mast rake (moving the mast base forward 2 inches) was, by experiment, faster. Base forward and forestay tight are contradictory, but faster by experiment in fast ice and high wind. I suspect the additional bend (and lower sail) moved power lower, allowed actual increase in speed and reduction in upsetting moment. The tighter shrouds kept the rig straighter than it could have been under my weight and the wind load. The plank was already very bent by pre-loading the tight fore stay. I also lowered the main on the mast. Hay, consider the context. I was in Bronze based on rank, and did well in every race. I would have lost my socks in Gold, most likely.
This brings up another lesson learned:
11. Never leave the main too low! In most wind, you can't get the leech tight enough if the main is too low. Can't accelerate and can't point, and have to fall way off to bend the mast. [I forgot that rule as I did not make that midstake all week]
Was my set-up truely fastest? Who knows, but the changes increased my speed reletive to the Polish competition in scratch racing, and proved to be very fast in the fleet racing during the worlds. I felt good and under control, worth some cajones down wind in the rocket sled.
When I say Loose/tight shrouds, without adjusting them, I really mean loose/tight forestay. I use a Sta-lock turn buckle with a handle, and can easily tighten or loosen the forestay. Let's define terms. Tight shrouds = forestay tight enough that when I stand on the plank, the shrouds are still tight. Twang. The plank is pre-bent past straight by the tight forestay. I can tell by the feel of the forestay turnbuckle when I am in this condition.
Medium shrouds = when I stand on the plank, the shrouds are still straight, but most of the tension is gone. Thwaa. The pre-bend in the plank just about removes all the crown. When sailing, the wind load causes some slack in the side shrouds. For my mast and weight, this is the 8-10 mph shroud setting.
Loose shrouds = just slack in the relaxed plank condition. Very slack in the sailing condition when some speed has developed. The shroud adjusters lay on the plank under sail. Light air.
My tuning sessions showed that the the fastest was with the mast base in a particular location in all but the heavyest wind conditions.
Other tuning combinations can probably achieve similar results, but this combination allowed me to have the boat set up and on the starting line. If the wind seemed to have diminished or increased by the start, a quick six-turn adjustment of the fore stay tuned the whole boat. The only substantial rig change came if the wind was very high. Mast step adjustment is too much for an on-the-line change.
Worked for me, I had a BLAST all week!
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