Sail Trimming

[StuM]

Originally Posted by sandy stone

Are you sure about that? On most boats (mine included) going to windward with the jib in tight, the car should be back to a pretty specific location so the luff telltales on the jib break evenly - with some slight variation according to wind strength. Then, as you turn off the wind and ease the sheet, the car should go forward as much as a couple of feet to maintain tension on the leech, especially at the top.

That depends on wind strength. In stronger conditions, you often want to reduce heeling and rounding up by de-powering the headsail through letting the upper leech fall off. That's why "spreadsheet rules" are not very effective - you need to get a feel for the most efficient trim and that may mean entirely different methods in different sea states and wind conditions.

[thinwater]

Originally Posted by Jman

To say the same as others: it is completely boat depended. No spreadsheet of settings. Even on a given boat as sails age (read stretch and lose shape) the trimming will change. Wind sheer (different every day) changes trim positions.

and in addition to windspeed...

• How much weight is on board.
• How clean the bottom is.
• Tide.
• Direction of the waves (may be deflected by land or sandbar).
• Depth of water (affects waves).

And this is what keeps us coming back.

[sailorscotty]

Thanks for all of the positive input. Don Guillette has done a Sail Trim Chart (spredsheet/table) which seems to address the information that i was looking for.

"The Sail Trim Chart lists all sail controls for the mainsail and jib and relates them to the full range of wind conditions from 1 knot to 15 knots"

No doubt a good starting point, irrespective of tides, boat model/condition, weight, blah etc.

If anyone is looking for similar information it can be found here:

Sail Trim Charts - Sail Trim Products

Big thanks to Stu for pointing me in the right direction cheers Scott.

[Jim Cate]

Are you sure about that? On most boats (mine included) going to windward with the jib in tight, the car should be back to a pretty specific location so the luff telltales on the jib break evenly - with some slight variation according to wind strength. Then, as you turn off the wind and ease the sheet, the car should go forward as much as a couple of feet to maintain tension on the leech, especially at the top.

Agreed! I think he got it backwards...

And if it is convenient, move the lead outboard as you move it forward while coming onto a reach... sure helps on our boat!

Jim

[GordMay]

Greetings and welcome aboard the CF, Scott.

[fahtcha]

The advise above on telltales will help the most. The Annapolis Book of Seamanship has an excellent explanation on trimming using telltales. In regard to the jib car. It should be forward in light air and farther back in heavy air. The jib is flatter when the car is farther back.

[Suijin]

Originally Posted by Jim Cate

Agreed! I think he got it backwards...

And if it is convenient, move the lead outboard as you move it forward while coming onto a reach... sure helps on our boat!

Jim

Doh. Yes my dyslexia strikes again!

[sandy stone]

Originally Posted by Jim Cate

And if it is convenient, move the lead outboard as you move it forward while coming onto a reach... sure helps on our boat!

Absolutely. When JAM racing I carry snatch blocks and temporary sheets for that very purpose.