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ISAF Cat 4 and Class Racing rules - Sails

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George Isted View Drop Down
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Joined: 08 May 2009
Location: Solent
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Posts: 375
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    Posted: 25 Apr 2013 at 2:52pm

Hi all,

I was just helping a new owner with a question around sails, the class rules and the ISAF requirements having measured his boat earlier in the week and I thought he same info may be of interest to other owners.   A question came up about this at the Cruising seminar a few weeks back so this may be a timely clarification for skippers that race.


For info, the Class rules have always required that boats conform to Cat 4 and this required all boats to carry a No 4 jib (which qualifies as a ISAF “heavy weather sail”).  So this IS NOT something new that has come in following the rule changes.


I hope this is of interest.


All the best.


George Isted

Co32 Class measurer



From: George Isted
Sent: 25 April 2013 14:30
To: *******
Subject: RE: Contessa Measuring




You have made me go and check the rules to confirm my understanding and check for changes, which is a good thing as the rules are updated every few years.  I have also been comparing the requirements for Cat4 against the full Cat0 rules.


For Cat 4 you need to carry what they called a “Heavy Weather Jib”, Class Rules also state that a No 4 must be carried.  It is therefore convenient that a Contessa No4 is the correct size for a ISAF “Heavy weather Jib”.


For Cat 4 you DO NOT need to carry what they specify as a “Storm Jib” or a “Trysail”, these are only necessary for Cat2 racing and above.


It is just the Storm jib that must have a “highly visible colour” patch or be made from similar material.   (I had Peter stick an orange blob onto my storm jib). So a plain Dacron No4 is just fine.


One ISAF requirement of note is…

for each storm or heavy-weather jib, a means to attach the luff to the stay, independent of any luffgroove device. A heavy weather jib shall have the means of attachment readily available. A storm jib shall have the means of attachment permanently attached


What this means is that IF the sail is designed to go into a foil such as that on a roller-reefing system it must have a separate means of attachment to the forestay.  A common but not easy to use solution is to have grommets (holes) down the luff such that short lengths of rope can be loosely tied around the forestay every couple of feet or so.   The reason for this is that under high-loads it is not uncommon for a luff-tape to pull out of a foil/furling system.


For info.   My No4 and Storm jib are set on an inner forestay that simply uses hanks, this does not require a secondary means of attachment because hank-on sails are pretty fool-proof.

George Isted
Contessa 32 "Concerto"
Co32 Class Measurer and ex Class Captain.
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