Thursday, September 8, 2011

Sail Construction/Weight

Those of you who read this blog will know that I am preoccupied with light sailing equipment and this post deals with some sail related weight issues.  The common sail material used in our industry has always been mono film.  This material is cheap, effective, easy to cut and fairly resistant to UV and wear and tear.  It is not light however and if you need the material to be stronger you simply increase the thickness of the film, adding to the weight of the sail.  Brands like Gaastra and North use this approach and I have a huge problem with them because of it.  I like their designs (some of my best sailing has been done on their sails) but not their materials.  Their products are simply too heavy.

One of the ways to reduce weight is to use laminates which sandwich a high tech fibre mesh between two thin films.  Modern aramids such as Technora, Twaron and Kevlar provide massive strength from minute weights of material.  Materials such as Dyneema and PBO (a liquid crystal polymer with even better stability and strength than the aramids) are also used in sailmaking.  Severne for instance, uses quite thick material on the hard wearing bottom part of the sail, Dyneema and Kevlar laminates in the mid section and pre-preg Technora film above the boom.  This makes the whole sail much lighter than a mono film equivalent and improves the swing weight in gybes and other transitions (as you can imagine with virtually no weight above the boom).  To give a comparison, the Gaastra Savage 6.7m weighs 5.1 Kg.  Severne's NCX pro 7.0m weighs 4.2Kg - almost 1kg lighter!  In addition to being lighter and stronger, what these scrim materials also allow you to do is to engineer some stretch into the weave.  Severne have done this with the NCX pro which can stretch at the limits of its wind range, allowing the sailor to maintain control and keep the board on the water - very cleaver!  Have a look at Naish's site and compare their sail weights with Gaastra and North.  Naish sails are substantially lighter.  If Naish and Severne can produce superior products with laminates, then other lofts can do it too.  

I am really excited by the new Gaastra sail shapes but I would implore them to go a step further and use some cool laminates to make a limited run of super light versions of their top performance sails.  I would then ask them to take a further step and  borrow the mast specs from Point 7, produce a bunch of these masts and launch them together with the light version sails.  Send Arnon, Ross and Alberto to a speed strip and log some impressive speeds to demonstrate capability and we'd  have some seriously exciting stuff on the market.  No harm in dreaming.

The performance and feel of a light sail can also be enhanced with carbon tube battens (instead of heavy GF ones) of course.  If your kit is light, easy, balanced and comfortable you are going to be faster and happier with your sailing sessions.  A light sail with low swing weight is one of the elements to achieve this condition.   I will expand on the theme of comfort and balance in the next post.

No comments:

Post a Comment