Submitted on May 23, 2005 by Jim Kelly

Question: Please explain to me what the designation of 100% or 150% genoa means? We are new at this and have roller furling jib which extends back to the cockpit when fully extended on our 25 ft. C&C.

I use snatchblocks on the toe rail by the mast and by the the cockpit to adjust the length of the jib. Isthis the way its done?

Thanks,
Jim

Answer: Hi Jim,

The 100%, 150%, etc designations are expressions of the width of the headsail, measured on a line projected from the clew to the luff at it shortest path (perpendicular to the luff), as a percentage of the length of the foretriangle. This measurement is called the LP%. LP stands for Luff Perpendicular. The foretriangle length is measured from the front of the mast to the point where the headstay connects to the deck. That measurement is called the "J" dimension. Nobody knows why.

A 100% jib has an LP that is equal to the length of the foretriangle. In that case LP/J= 1.00, or 100%. A 150% sail is 50% wider than J, which means that it projects well aft of the mast.

It sounds like you are using your genoa tracks correctly. If there is a second track inboard of the toe rail, that will be a better place to sheet the sail when you are sailing to windward. The toe rail is better for reaching angles.

There are a couple of rough guidelines to determine the best position along the track. When you are sheeted in all the way, the headsail should touch the shrouds at the foot of the sail just before it touches the spreader tip. When the sheet is in the correct position, an imaginary line, projected along the sheet and extending all the way to the luff, should intersect the luff of the sail halfway between the head and tack.

Regards,
Dan Neri

Email North Sails with your question today!

Go BACK to Solutions for Sailors Main Page.