Measurers Corner

Measurer’s Interpretations and Recommendations

Topic:Control Lines
Question:Is the allowed purchase of the mainsheet 8:1 and can this be accomplished with a fine and coarse set of blocks?
ID Number:000004
Short Answer:Yes 
Answer:The Class Rules are quiet on this. The technical committee has agreed that 8:1 should be allowed and it may be comprised of a course and fine control. Changes to the Rules are in being proposed to make this clear. 
Action Date:2008-07-09
Wed Apr 17 03:26:23 2024
2007-10-27Richard RobbinsNormally the mainsheet is rigged with a 4:1 purchase. The "Blue Book" seems to be quiet on what is allowed but every where else that the purchase is specified it is up to 8:1. Some boats sail with 3:1 and others have used (or want to use) more then 4:1. I would tend to allow anything up to 8:1. As to the fine and course sets of blocks it could be argued that since they are not on the official plan it would not be allowed but I am open to ideas on this part of the issue.
2007-11-16Richard RobbinsRelevent Sections include: Section 4 - 6.4 Mainsheet Bail - A bail for the Mainsheet turning block shall be located 13 feet 3/4 inches from the after face of the mast. The turning block may be a double block. Section 4 - 8.1 Mainsheet Trim Arrangement - The location of a block and cleat on the boom for adjusting the mainsheet is optional. (See specification 6.1 and Section VII - Official Plan 2)
2008-03-04Kristian MartincicAsk any main trimmer who was at day 3 of the 07 Nationals: more purchase on the mainsheet would be a great thing! It seems that both the allowable purchase and the location of hardware for this system could be made much clearer in the blue book. I think that rule 8.5 (traveler controls) makes a good model for this type of rule, when it states that the arrangment and lines are optional, but limits the purchase to 8:1. A gross tune/fine tune arrangement would be very effective, and not difficult to add to the boat. My first thought would be to add an 8:1 fine tune to the 4:1 mainsheet, and lead the line to a small pivoting exit block (Harken 299) on the boom, in a very similar fashion to the current block and cleat assembly. If this were made legal, my only gripe would be that it came after I traded in the main trim spot for driver!
2008-07-30Richard Robbins8:1 with fine/course control adopted by Governing Board July 29, 2008. See July, 2008 Version of Rules.