Mainsail trim questions
- Thread starter Plankton
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Full power from the main using the travller would come from increasing the angle of attack ie raising the travler to windward. If the travller is in as much as possible the boom shound be no higher than the centerline of the boat.
Travller all the way to leeward would be on a run along with easing the sheet to just keep the sail off the spreader.
The mainsail cannot be trimmed properly using just the traveller or mainsheet alone. One must control twist,angle of attack,and placement of pocket fullness in sail to match wind conditions and point of sail.
Travller all the way to leeward would be on a run along with easing the sheet to just keep the sail off the spreader.
The mainsail cannot be trimmed properly using just the traveller or mainsheet alone. One must control twist,angle of attack,and placement of pocket fullness in sail to match wind conditions and point of sail.
We use the traveller to balance the boat after the sheet has been trimmed. Starting with the boom on centerline or a tad to leeward, as Roy suggests, we drop the traveller to leeward if there's too much weather helm. Having to keep the rudder turned a lot in order to keep the boat from heading up into the wind slows the boat down. Dropping the traveller eases this pressure and helps the boat go faster. If it's blowing hard, we may need to drop the traveller down as far as it goes. If it's puffy we often cleat the sheet off and play the traveller by itself. If the wind picks up (to about 20 knots, for us) it may be time for a reef.
Your question requires a very complex answer, more than what can be placed on a simple forum reply.
There is needed a 'balance' between what you call power and speed ... and they are not the same when it comes to shaping and trimming sails.
The 'ultimate' answer is contained by what a full set of tell tales are telling you, as every boat is different and every time you take the boat out the wind/waves and their interaction on the boat will be very different.
Id recommend that you start at the 'beginning' with such things as Don Guilettes' "Sail Trim Users Guide" (http://shop.sailboatowners.com/prod.php?51999/Sail Trim Chart and Sail Trim Guide) and then 'work your way up from there as regards trim and sail shape. Shape refers to what YOU do to alter the shape of the sails to meet the conditions you're sailing in.
Once you can master the 'basics' of telltale usage, you can also join such trim forums such as http://forums.sbo.sailboatowners.com/forumdisplay.php?f=17, etc.
If you dont use 'tell tales', ... pulling on sheets, outhauls, halyards, travelers, etc. will always remain 'mysterious'. Tell Tale usage is the fastest way to 'master' sailing. Its really a consideration of SAFETY as well getting the 'optimum' out of a sailboat.
;-)
There is needed a 'balance' between what you call power and speed ... and they are not the same when it comes to shaping and trimming sails.
The 'ultimate' answer is contained by what a full set of tell tales are telling you, as every boat is different and every time you take the boat out the wind/waves and their interaction on the boat will be very different.
Id recommend that you start at the 'beginning' with such things as Don Guilettes' "Sail Trim Users Guide" (http://shop.sailboatowners.com/prod.php?51999/Sail Trim Chart and Sail Trim Guide) and then 'work your way up from there as regards trim and sail shape. Shape refers to what YOU do to alter the shape of the sails to meet the conditions you're sailing in.
Once you can master the 'basics' of telltale usage, you can also join such trim forums such as http://forums.sbo.sailboatowners.com/forumdisplay.php?f=17, etc.
If you dont use 'tell tales', ... pulling on sheets, outhauls, halyards, travelers, etc. will always remain 'mysterious'. Tell Tale usage is the fastest way to 'master' sailing. Its really a consideration of SAFETY as well getting the 'optimum' out of a sailboat.
;-)
Control Angle of Attack with the Traveler, then Mainsheet
While the end of the boom is over (or near) the traveler, the traveler controls the angle of the main to the wind. The mainsheet controls twist, allowing the top of the sail to fall off the wind.
Once the end of the boom is downwind of the traveler, the mainsheet controls the angle of attack of the main, while the vang controls twist. If you don't have a vang, once the boom is off the traveler, you cannot separate twist and angle of attack. That is, easing the mainsheet will increase angle of attack, _and_ increase twist.
Don Gillette's guides will tell you how to read your telltales, and optimize your sail with these controls.
Keep at it! Tuning your sails is straightforward, but you do need to know what you are doing, and what each control does for you.
While the end of the boom is over (or near) the traveler, the traveler controls the angle of the main to the wind. The mainsheet controls twist, allowing the top of the sail to fall off the wind.
Once the end of the boom is downwind of the traveler, the mainsheet controls the angle of attack of the main, while the vang controls twist. If you don't have a vang, once the boom is off the traveler, you cannot separate twist and angle of attack. That is, easing the mainsheet will increase angle of attack, _and_ increase twist.
Don Gillette's guides will tell you how to read your telltales, and optimize your sail with these controls.
Keep at it! Tuning your sails is straightforward, but you do need to know what you are doing, and what each control does for you.
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