Why did sailors start experimenting with spreader rake and diamond wire tension..
They wished for a rig that was faster by automatically responding to small changes in windspeed. Depower in gusts and polering up in the lulls without the crew needing to do anything.
Spreader rake and diamond tension in the base form shapes the start setting for the mainsail. Draft and leech shape.



With a new Nacra i believe the supplied assembly manual specifies spreader rake and diamond tension to match the sails? I dont know the number but surely they are available online?
Beboere experimenting with spreader rake and diamond tension different then the factory /sailmaker spec, quite some time in the boat or a very broad beachcat experience is a prerequisite for good results in my opinion. This is a very fine grained tuning tool compared to sailing the right lane, boat balanse, helming, sheeting, starting, downhaul, roundings etc. I would run with the factory spec until I had the rest of the skills well done. On our current Nacra F18 that is exactly what we do. The settings are not what slows us down. It is our own boathandling and on the water decisions.