Fillah Karim is a Canadian Laser sailor and member of the West Coast Sailing sponsored sailing team. He was an early adopter to the new Laser Mk2 Sail, class approved by ICLA, and has learned the ins and out and nuances of this new sail. Check out the following Laser Mk2 sail tuning guide along with his notes and observations, which should prove useful for anyone transitioning to this sail or looking for trimming tips.
Overall, A Better Sail - The new sail is definitely better than the old one. I was hesitant with the switch, but the new sail has better material, better shape, and tapered battens.
Speaking Of Battens - Make sure that you put them in correctly! Tapered end goes in first. After sailing, make sure you either remove the battens or at least release the batten tension. Leaving all of that load in the sail may cause the batten pockets to wear prematurely.
Cunningham Adjustment - If you were using the 3:1 cunningham system with the old sail (as most people were) you will need to change to add an additional purchase. This is done by changing the single block at the top, to a double block.
Beware Of Top Mast Collar - With the new sail, you will still need to pull on the cunningham line with as much force as you had to with the old sail. Except now, you are doing it with a 4:1 purchase. Effectively, that means that there is substantially more load on the rig to achieve the desired outcome. This has lead to some weakness in the plastic top mast collar on some aluminum top sections, but has not been noted with the new composite top section.
Break In Period Extended - The necessary break in period is longer than with the older sails. Historically, you only needed to sail on it one or two times before you would race on it. With the new sail, I would suggest a minimum of 5 uses before a regatta, depending on conditions.
Leech Tension - The leech is tighter on the new MK2 sail, and the boom will sit slightly higher. You will need to loosen you max off setting on your boom vang. There will also be more mainsheet load upwind, and as such it is harder the keep the sheet in. Some sailors may be tempted to pull on boom vang too early to lessen the load, which would be a mistake and make the boat less powerful.
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