Mike Firth’s Blog – Mylar v Dacron

I recently visited my sail maker – as in McNamara – and
discussed both Mylar and Dacron. He had equivalent rolls of material of each in stock and I can confirm that the Mylar ‘felt’ marginally lighter, As a raw material the Mylar costs the sail maker between 35% and 40% more than the equivalent amount of Dacron, I was given to understand that the labour and skills involved in manufacture were similar.

I was advised that in comparable circumstances, as in dinghies and small keel boats, we should expect the Mylar to have approx half the life of Dacron. To be more specific Mylar is particularly sensitive to abrasion and flapping/flogging – they call it ‘wragging’ -. The growth of Mylar on the dinghy scene is associated with the growth of the new generation of bow sprit skiffs – euphemistically some times referred to as lollipop boats – where the latest materials are ‘derigour’ and the ‘image’. The self taking jibs on these craft are heavily supported by reinforcement and battens, whilst the majority of mainsails are fully battened. Plus they are rigged on shore, where the carefully rolled mainsail can be fed up the mast, where it will be supported by the battens thus eliminating a degree of flapping.

With the Flying 15, in the case of the foresail/genoa, the consequent overlap causing abrasion on the mast plus furling, means that Mylar is an unsuitable material. In the case of the mainsail, which is not fully battened and hence less supported, one also has to consider all that Mylar ‘scrunched up’ in the floor of the cockpit prior to hoist. This is where a substantial amount of attrition will occur, in addition that on the race course.

Two significant other established dinghy classes have adopted a Mylar option for their Mainsails, the Fireball and The GP14. In the case of the Fireball, a class that was significantly under pressure from the skiff type craft, the members voted for the for the option because they believed it would update the image of the class. The average retail price hike between a Dacron and a Mylar mainsail on the Fireball is 22%.

In the case of the GP14, the council made the decision to allow a Mylar option, there was no vote invited from the membership. The GP14 situation is quite similar to that of the Flying 15, where just a few sail makers seem to have developed a bit of a monopoly – cartel is perhaps too strong an interpretation – nevertheless some members of the GP fleet were bemused by the decision towards mylar. In the case of the GP14 the average retail price hike is just over 19%.

So there we have it, Mylar costs more and sails made of this material will have a weight benefit, but unless correctly supported, will have a shorter life. Currently sailmakers are charging substantially less for a complete sail, than the increase in the cost of the raw material used. Is this because they are trying to establish a new market segment or do they expect to make twice as many sails long term?

Non Dom

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