R22 Discussion Group

On Aug 7, 2025, at 9:26 AM, Ric Stott <ric at stottarchitecture.com> wrote:

Hi Todd,

My OEM standard mainsail had 2 rows of reef points.  The picture shows a fully battened mainsail that I had built for me.

Yes, any sail loft will be able to add as many reef points as you wish.  My 3rd reef was added after I’d had the sail for awhile.  I wanted it for Great Lakes sailing.  For inland lakes, you could probably get away with 2 reefs.  Of course, you would need to add the required hardware on the boom for every reef point you add.  If you have existing reef hardware; then, that determines the location of the reef points on the sail.  You would specify the location of the reefing hardware on the boom to your sailmaker.  If you are adding reef hardware; then, the reef points can be anywhere you want.  I would stay away from batten pockets and don’t put a reef point tack grommet near a sail slide.  My reefs angle up for the sake of luff tension and also to provide a little more head clearance under the boom.  My boom topping lift is rigged to a cam cleat on the clew end of the boom.  If I want to have less leech tension while reefed, I just trim the topping lift.

As far as where to locate the reef points, there are 3 factors in play.  The 1st is sail area.  For this, sail can be treated as a triangle, making the area easy to calculate.  Remember, the wind force goes up as the square of the wind speed.  ie, Doubling the wind speed results in 4X more force and the force is proportional to the sail area.  The second factor is that reefing the sail causes the center of pressure to be lowered, resulting in less heeling moment.  The 3rd factor is the center of pressure also moves forward when the mainsail is reefed.  This results in less weather helm when heeled over.  By reefing the mainsail, you can leave more of the genoa flying, resulting in better sail shape and more boat speed.  Even if you heel over, the helm will remain balanced and you won’t have to use much rudder, resulting in less drag and more boat speed.  It’s also much less tiresome for the helmsman.  The reef point locations in the photo seem to work pretty well.  So, feel free to scale them off the photo.

In the photo, note the curvature in the foot of the sail.  When rigged, this curvature results in a very full ( ie deep draft ) sail shape.  This shape is appropriate for light air.  When the wind speed increases, the sail shape needs to be flattened.  Another reason for the slant in the reef point locations is to remove the deep draft from the belly of the sail.

In the photo, I have a yellow tape measure stretched from the head of the mainsail to the clew.  You can see how much roach the sail has.  Note, this much roach will require a fully battened sail.  Also, this much roach required the static mast tilt to be adjusted such that my mast has almost zero degrees of aft rake angle in order to adjust out the weather helm when the mainsail is fully deployed.  All the extra roach sail area is in the extreme aft part of the mainsail, where it wants to cause weather helm.

Roger Pihlaja
S/V Dynamic Equilibrium
1976. Sanford, MI
Sent from my iPhone

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ROGER PIHLAJA

Shortening Sail