San Juan 21 Class Ruling - Loose Footed Mainsail

Mike Chesser, Chief Measurer - 12/20/10

There has been a great deal of discussion through the years on the issue of whether a loose footed main should be allowed. Proponents of the loose foot main prefer the ease of installation of the sail on the boom. The majority of opponents to the loose foot main are concerned with the potential for an unregulated foot dimension resulting in increased sail area.

In discussion with several of the Class’s sail makers, it is clear that the costs associated with fabrication of a loose foot main will not be any more than the current boltrope main. Likewise, it is clear that there is no compromise to the boom integrity with a loose foot main in use compared to the standard boltrope foot main. There are neither identifiable competitive advantages, nor disadvantages associated with use of a loose foot mainsail. Furthermore, after considering the typical dimensions of the foot shelf commonly found on the boltrope mains, it appears that the class can easily control the sail area with an easily measured foot roach dimension.

Therefore, I am recommending to the Executive Committee that the Class modify the Class Specifications, Section 3.5, Article V: Sails, 2.0 Mainsail, to allow the use of a loose foot main with appropriate changes to also control the foot roach. Attachment of the mainsail to the mast will remain the same for either type sail. Attachment to the boom for the boltrope foot main will remain as currently defined. Attachment to the boom for the loose foot main shall be by way of the existing tack pin and slug attached to the clew of the mainsail. Maximum Foot Roach shall be 4 inches.

Click here to view a revision-marked copy of Section 3.5.

3.5 Article V: Sails.
  1. General: San Juan 21's may carry mainsail, jib, genoa, and spinnaker, as shown in the sail plan and as herein specified when racing in Class Association races. Only two suits of working sails with genoa and spinnaker will be approved for use by a contestant in National Regattas.
  2. Mainsail:
    1. The luff of the mainsail shall be attached to the mast and boom by arrangement of its boltrope (or slugs attached thereto) in the grooves of the spars. Loose-footed mains are prohibited allowed. The foot of the mainsail shall be attached to the boom by either its boltrope in the grooves of the spar, or if loose-footed, by the tack-pin at the tack and a slug at the clew.
    2. Luff and foot measurements shall be controlled by the band system.
    3. Sail measurements shall be made with sufficient tension to draw the cloth smooth and taut. The leech chord, measured from the aft corner of the headboard, shall not exceed 24 feet 6 inches. The girth, is measured at 90 degrees to the luff chord, at 6 feet 0 inches, and 12 feet 0 inches down from the head. At 6 feet 0 inches down from the head, the girth will not exceed 3 feet 11 inches. At 12 feet 0 inches down from the head, the girth will not exceed 6 feet 3 inches. All measurements will include the boltrope. Maximum foot roach is 4 inches.
    4. Battens shall divide the leech chord into equal sections with 2-inch tolerance to avoid seams on all but the top batten. The aft top corner of the top batten pocket will be a minimum of 56 inches from the aft corner of the headboard. Maximum batten lengths are: upper - 24 inches, two middle and lower - 36 inches.
    5. Hollows in leech between battens are not to exceed 3/4 inches in roach.
    6. Headboards shall be triangular, with the upper side of the triangle not exceeding 4 inches in length.
    7. The mainsail shall be made of 3.5 oz. or heavier woven material. Mylar or other film construction is prohibited.
    8. A Cunningham or sail control grommet is permitted.
    9. A reefing zipper on the mainsail is not permitted to be used while racing. Roller, slab or jiffy reefing is allowed.
    10. Windows in the mainsail are permitted.

San Juan 21 Association Class Rules

These manuals are in PDF format.

US Sailing Resources

San Juan 21 Executive Committee Meeting Minutes

The San Juan Executive Committee meets via conference call every three months (or so) to discuss the current state of the Class Association and where we are going. Minutes of those meetings are now published after approval. If you have any questions/comments, please don't hesitate to contact one of the committee members. (Click on a date to show/hide the minutes for that meeting.)

November 7, 2017, 4pm PST/7pm EST

Attending: Bob Abelin, Mike Chesser, Robert Booknight, Kris Barker

Regional reports

  • East coast report - Rob Booknight (Eastern Vice Commodore)
    • North American National Championship - 22 boats participating. Light winds but got in 2 good races. Link to results posted on the National Association website.
    • Not much discussed at the nationals meeting but regarding the Eastern Nationals next year, Mike Chesser is going to check w/ the Fishing Bay Yacht Club (Deltaville, VA) to see if they will host that event next summer as part of their One Design Regatta the weekend of August 11, 2018. There is no fleet there, but Mike is a member and there have been SJ21 boats at other events. He'll contact them after the first of the year to see what's possible.
  • Midwest report - Bob Abeline for Jay Sawyer (Midwest Vice Commodore)
    No midwest national event; popular regional events are posted on the website.
  • West coast report - Bob Abelin for Sean Randle (Western Vice Commodore)
    • Western National Championship (Huntington Lake, CA) - 15 boats, got in 5 races. Link to results posted on the National Association website.
    • Coos Bay has volunteered to host North Americans next year - tentative date is 7/27-28/2018.

Exec Committee reports

  • Chief Measurer - Mike Chesser
    • We've been trying to get a set of keel and rudder drawings for several years. Mike works with a guy who has offered to help. In 2011 we approved $150 to offer someone to help. Mike asked if that offer was still valid. Committee says yes and proposed that the amount be increased if needed. Mike will start there and see how it goes. We'd ultimately like to get not just a set of acurate measured drawings, but eventually ones that can be used in manufacturing.
    • Kris mentioned that Stephen Jensen (San Juan Sailboats) has asked about use of materials other than fiberglass and wood - specifically plastic - for rudders given recent issues with finding fiberglass manufacturing options. Mike mentioned that drawings control dimensions, but there is some latitude on materials. Kris to talk to Stephen about submitting a proposal that can be evaluated by Mike and the committee. In most cases, safety is the prime issue.
  • Treasurer - Bob Abelin for Cal Guthrie (not present)
    • Current balance: $10,839 ($9,351 carryover + $1,488 new memberships)
    • 71 paid members
    • ~$1,250 in expenses yet to pay this year
  • Web - Kris Barker
    • This year's national results posted to website

National Association Officers for 2018

Bob proposed the following:

  • Eastern Vice Commodore - Robert Booknight
  • Midwest Vice Commodore - Jay Sawyer
  • Western Vice Commodore - Marc Vander Schalie
  • Chief Measurer - Mike Chesser
  • Treasurer - Cal Guthrie
  • Webmaster - Kris Barker
  • National Commodore - Kris Barker
(Bob magnanimously agreed to continue participating as Past National Commodore.) A motion was made to accept the proposed roster. The motion was seconded and approved unanimously.

New Business

Rob brought up a couple of things:
  1. There doesn't seem to be too much web presence on the east coast. He'd like to find a way to encourage participation and communications among easter sailors and fleets. There was discussion around a Facebook presence, participation in existing forums, and posting of information on the national site. Kris mentioned the key is always finding ways to generate new/interesting content.
  2. Wondering about the possibility of a fleet-owned SJ21 for use:
    • Bob mentioned that we'd received an offer to donate a boat from Bill Cox in Ohio and forwarded that email to Rob.
    • Mike mentioned that one issue that often comes up in trying to do this is insurance which is typically a requirement.

The meeting was adjourned at ~5:00pm PST/8:00pm EST.

San Juan 21 Manuals

These manuals are in PDF format.


The JibSheet is a publication of the San Juan 21 Class Association and is currently edited and published quarterly by Calvin Guthrie.

Mini Aids

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