Sail Material specification change needed??

[Jeff Kent]

To fellow TC members,  i have been contacted by Rafal Sielicki  P-254     Commodore of Polish DN Fleet  with the following letter;

Dear Jeff,

Hope you are well.

As a Commodore and active competitor of DN class I want to share with you my thoughts about Karol Jablonski sail cloth proposal.

First of all the DN class rules should be clear with no room for overinterpretation.
I know that TC is working on that already so I think that’s good time for clarify sailcloth specification too.

Today’s specification is :

Sail (specifications)

1. The cloth must be made with high tenacity polyester (dacron) yarns. Sail cloth
   must be made with either of the following cloth constructions: 6.5 oz. cloth
   with 220 denier warp and 440 denier fill yarns or 280 grams/square meter
   cloth with 250 denier warp and 410 denier fill yarns.

 1.Sail ( interpretations)

1977: It is not legal to use two ply Dacron 6.5 oz cloth for the top panel and bottom

panels for reinforcement.

9/1/99: It is legal to use Contender 6.5 oz. Polycote cloth in the construction of the sail.

Which means we have two sailcloth suppliers with different weight ( 6,5oz is not exactly 280grams) and also different arrangement in denier warp and fill ( Contender 200x 440, Polyant 250 x 410). These are not the same products, but I’m completely sure that this difference has no any advantages or disadvantages to one of them – just look at the results of top sailors using both types of cloth.

That’s why I agree with Karol that to keep denier warp and fill in the sailcloth specification is pointless. Moreover all producers in the world doesn’t matter if they produce sailcloth, textiles or other materials they produce with specified accuracy, which means that there can be and for sure there is batch to batch difference  in weight as well as denier warp and fill, which means that two sails made from different batches of sailcloth are not the same, but again it has no effect on the sail performance at all.

As long as the grammage of sailcloth can be measured in workshop conditions, then to measure weft and warp is impossible.

Another think comes to my mind: what if somebody will find new sailcloth (e.g. in China)

which will be cheaper but with slightly difference in construction or weight – 275grams for instance, from DN class point of view this is good to have cheaper equipment which allows to acquire new sailors, but this type of sailcloth is illegal due to class rules.

Summarizing: we should get rid out of denier warp and fill and specify the tolerance +/- 5 or 10%. And in my opinion TC could decide that change directly without the ballot, because most of the people are not aware of that issue at all.

As I know following topic was added immediately  to class rule without ballot :

9/1/99: It is legal to use Contender 6.5 oz. Polycote  cloth in the construction of the sail 

Jeff as a Chairperson of Technical Committee how do you see the way to implement these changes? In my humble opinion it should be done asap, that in coming season everything will be legal.

Waiting for your reply.

Kind regards

Rafal Sielicki

P-254

Commodore of Polish DN Fleet

As TC chair    i acknowledge that out specification can be confusing but at the same taime ove r the decades the sailmaker have done a good job working with them. to my understanding  the materials do change from roll to roll and selective inspection has been done to get best quality fabric to meet their requirement’s.  the rolls still met the class specification within the specific allowed denier counts   but the sailmaker might not liked the quality or some other aspect of a specific roll of product.

In my opinion the class does not have a real big issue here to deal with.    some sailmakers are requesting to open the specifications to say a specified  areal weight cloth only similar to what we use currently,    However no warp and fill counts. Specified.  this will open sail material to many variants on 6.5 oz  cloth . Currently the ones we specify are nearly a balanced weave  warp x fill     with their suggestions  a warp oriented cloth could be used satisfying the 6.5 oz requirement but it is a totally different material.  with these material  full radial designed sails would be legal.   honestly not sure if they would be be better or not  that would be for the sailmakers to persuade  us  the sailors.

Again my opinion,   they would look cool as compared to our simple crosscut sails , possible could have better control to get a better designed shape. . I do believe they will be more costly though as they are considerably more seam etc..

being on the board  i ask you to read the above letter and consider what direction the TC  should go on this.

the class may be be calling for this change  . so far I have only heard it from a very few.

I look forward to you responses

 

best,

jk   TC  chair

[Peter Hamrak]

I think sailmakers have pointed out this issue several times. The current rule has certainly unnecessary regulations. I agree to change the rule. I would let all dacron sail materials legal.

I would go even further as I would let laminate sail materials to use with the restriction to only polyester based reinforcements.

This would be a small change in specifications and a huge one for making the class look more acceptable to today’s standards.`

[Jeff Kent]

Does the rest of the board have any opinions to this?

[Richard Larsson]

Thx for asking!

First i think we should make some change. I find two pretty good ways of doing that.

Now we handle this issue by specifying specific types. If i understand correct we have two brands to choose from. If there are some other cloth that we want to make available we could just put it in next to the others.

The other way is to make max and min of the three parameters. Thickness/wheight, x denier warp and x denier fill yarns.

If we skip to limit the denier we increase the risk of change how the sails are made in the future. Maybe the sails are good as they are.

Rafael make o good point

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