36" Class - Proposed Rule Change There has been a proposal by Dave Kent to amend the class rules and the MYA Technical Team under Roger Stollery have been asked to prepare a report on the subject. The proposal is to remove the restriction on spar material in rule F.1 A copy of the Technical Teams Report is attached for your consideration. Registered owners wishing to make comment are asked to do so on the MYA Forum, and there is a section set up ' Rule change Carbon Masts' within the R36 section. We are allowing 2 weeks for discussion to say 1st February, and any useful comments will be taken on board by the Technical Team. Following this we will be conducting a vote of the Owners as to whether they wish to make this rule change. This vote will be conducted by e mail. Details of the Proposals are being put on the MYA website, and if you are aware of any owner who has not been e mailed please ask them to contact me. Peter Moore Class Captain 16th January 2017 36" class rule review - remove spar material restriction? - Technical team review The revision of this class rule in 1991 rule added the restriction on the materials for spars to aluminium or wood. In the objectives for the rule review in 2004, removing the restriction was considered, but it was rejected. At that time carbon spars were used on all the other classes apart from the IOM. It must have been considered then that the extra cost would not be in the best interests of the class. Since then the price of carbon has dropped considerably and carbon tubes no longer attract a cost penalty and are more readily available from many sources. As there is almost total freedom in the class rules, apart from the requirement to fit in the measuring box, isn’t it now appropriate now to reconsider this question? Dave Kent has put forward a proposal to remove the spar material restriction in the 36” class rule F.1 and this is what has prompted this review. There are many considerations to be taken into account and some of the advantages and disadvantages of carbon against aluminium are listed at the end of this document. You need to decide what you want from your class. Currently, it is at a low ebb with a few more radio boats being registered than vane boats. It is a fun boat to sail, not very stable and needs a lot of rigs to compete in all conditions. The most important feature is the design freedom with the chance to experiment in rig design, with almost total freedom outside of the measuring box. In a world of boring one design and more restricted open classes, opening up the freedom in the 36” class may attract more designers wishing to develop ideas for more performance and push the class forward. The use of carbon in the rig throws up more opportunities than just replacing aluminium tubes with carbon tubes, because wing masts and wingsail rigs could enhance performance in stronger winds and make the boat more exciting and even more fun than with the current restriction. Comparing the advantages and disadvantages there are a lot more advantages to the use of carbon, so shouldn’t we consider very carefully restoring the original 1930s rule and remove the relatively recent, but now outdated restriction of 1991? Before considering the comparative advantages of change etc in the table below, Graham Bantock provided some useful comparative information. For the record, SAILSetc carbon tubes have a material stiffness of 190-210 GPa, whilst the commonly available tubes are typically 80-100 GPa. To put the above figures into context; aluminium alloy has a material stiffness of 70 GPA and a density 70% greater than carbon. The inference is that cheap carbon tubes are twice as good as alloy, top quality carbon tubes four times as good as alloy. Cost wise a 1 metre length of IOM spec aluminium 11 mm tube is in the order of £8, whereas a basic carbon 10 mm tube from Carbon Profiles is £7.56 and SAILSetc’s stiffer 10mm carbon tube is £39.50. However, with relatively short rigs in the 36" class, unlike tall rigs for Marbleheads, the extra stiffness is probably not needed. This review document is for an owner discussion on the MYA forum. After a two week period, any useful comments will be taken on board and a voting paper sent out to all owners by the class captain, Peter Moore. Roger Stollery on behalf of the Tech Team 2016-12-23
