Sail Handling Tips:
Here is an interesting description from Charlie Ogletree at Ulman sails on how to trim the main when going down wind. .
Downwind VMG How should I be trimming my mainsheet for downwind VMG? Should the leach telltales be flowing? The tuning guide says the vang is important and should be held in the crew’s hand. Should the vang be used to keep the telltales flowing, or just preventing a broach? – David Crall
The vang is important and should be adjusted constantly. There are two modes of downwind sailing, displacement and planing. In displacement mode sailing, you are trying to sail low with the main fairly eased. In this condition trim trim the vang so the top batten remains parallel to the boom. This will require slight vang adjustments depending on the wind velocity. The leech telltales should all be flowing most of the time. The top can stall about 20% of the time and be okay. In planing mode, you are sailing higher angles and much faster with the apparent wind forward. In this mode the boat should be kept very flat. To sail this way the vang should be eased so the top of the main is very twisted, almost luffing, and the boom is trimmed in close to the leeward rail of the boat. With the vang eased like this you can steer the boat around the waves with out the boat loading and heeling. If the vang is too tight in these conditions the boat will load and heel as you head up to plane or miss a wave. The vang line should be in a crew’s hands so the crew can tighten the vang in the lulls and ease it in the puffs. It is a huge speed control in these conditions. Regards, Charlie Ogletree