Sunday, April 29, 2018

Reducing friction in single-line reefing

New system at luff
New system at leech






Rings atttach to leech via Dyneema loops.  The crossover
is at the far side of the ring, as shown with the black mark,
so that the loop is reinforced with the seizing















The friction in my reefing system was making feel not confident that I could reduce sail in a blow.  With the reefing line on a winch, in moderate winds, the resistance led me to bust the block at the base of the mast which turns the line back toward the cockpit.  I believe I have solved the situation by attaching low friction rings at each of the mainsail's six reefing cringles.   A test of my new system in 15kt winds on a narrow reach showed significantly less resistance with an ability to pull it in by hand.

Rings attach to luff with webbing. Sewn and seized
The friction in the system occurred where the reefing line passed through the rings pressed into the sail, one in the luff and one in the leech for each reef.  At each pressed ring, the line is forced to make a low-radius, 180 degree turn around a non-smooth surface.  Low-friction rings allow the line to be turned over a smooth surface with a larger radius.

The webbing attachment uses a ring while the Dyneema
loops are built going through the leech cringle
Before going with low-friction rings, I had actually bought blocks that I was going to attach at the sail cringles. In my perseverations about the weight I would be hanging from the sail, I learned about the option of using low-friction rings from the Justine Owners Facebook group. My local sailmaker, Tim at Sailcrafters, helped me figure out how it was probably done.


I attached the low-friction rings to the leech with Dyneema loops.  These are easy to do, clean looking and strong.  I got the advice to make the loops 6" long (when collapsed) from Jaimie at Sailing Totem.  Six inches is about as short as you can make it using 6mm Dyneema line.

Dyneema loop before the ends are trimmed and drawn into
itself.  This has been floating around our house for months.













There are good videos on how to make Dyneema loops.  Bury 6" on each side for a loop made with 6mm line (whatever the diameter of the line in mm, you bury that much in inches).

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