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Permitted sailcloth

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John Shelton View Drop Down
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    Posted: 11 May 2010 at 12:54
Forgive me if this has been done to death, but a discussion in the clubhouse at the Shoreham open got my grey matter moving regarding the above.
The newly formulated class rules specifically state that the sails shall be made of polyester and/or HMPE (or at least the ply part of the sails).
Now, on the basis that nothing else is explicit in the rules, then everything else must be banned.
HMPE is either Dyneema or Vectran (depending on who makes it).
Carbon reinforcing is therefore not permitted, so what sort of construction is available to us? For example, is the construction favoured by the Fireball class permitted?
 
I would be keen to see a sail construction which improved the longevity of sails, and my experience with mylar constructions in the past is that they keep their shape longer, before the onset of rapid decline.
I notice Mr Cooke has gone back to Dacron Wink
 
Thoughts?
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Tom Guy View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tom Guy Quote  Post ReplyReply Direct Link To This Post Posted: 11 May 2010 at 15:38
 
Interesting. The Meatballs do not actually stipulate the material only the construction. Our rules are split in to construction and material, but the F/B's only material but then goes on to describe the construction!
 
 
 
20.2 Material

Sails shall be single ply soft sails made of woven or laminated ply.

Looking at the P&B sails, they use Dimension Technora which is an aramid fibre-based laminate. Presumably these cannot be used for Hornets (not HPME or polyester fibre).
 
The Scorpions also do not specify the material only the construction - seems like we are misaligned?
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John Shelton View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Shelton Quote  Post ReplyReply Direct Link To This Post Posted: 11 May 2010 at 22:02
The penalty for adopting the RYA template it appears. In theory, we could have pure Mylar unwoven sails too.
Maybe it's worth trying to get a determination from the RYA. I think it would be useful to be able to piggyback off the Fireball/Scorpion technologies.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Steve Cooke Quote  Post ReplyReply Direct Link To This Post Posted: 13 May 2010 at 09:32

I went to Dacron after a long discussion with Alan Bax. The gist of it was that with the restrictions placed on the class by the rules regarding permitted materials in sails, there was no noticeable benefit to be gained by using laminate material in terms of either weight saving, longevity or shape retention, and the cloth is about 20% more expensive. My laminate sail had polyester fibres to comply with the rules, but because of this the fabric had no weight saving over Dacron as both are made from the same base material and there has to be a high minimum fibre content in the laminate to hold the strength. As has already been stated, laminate cloth is very stable for a certain period but then has "catastrophic" breakdown, which translated means that the sail maintains its shape for a reasonable working life and then suddenly goes out of shape, as compared to a Dacron cloth which stretches a little bit each time its used so the performance degrades over time. My laminate sail had a good shape generally so I had no complaint on the power side, but I wasn't too happy about the "fairness" of the finish, as there were noticeable ripples running vertically in some areas, and I couldn't get the head of the sail to hold shape off the wind in light to medium wind strengths - a result of the two very high top battens. I went for a new sail after noticing that the vertical ripples had got much more pronounced at the end of last year, suggesting the sail had reached that "catastrophic" point, even though it had only been used about 35 days in total, and as you know, I try to avoid strong winds! Alan was certain he could make a good Dacron sail, and having been pleased with the laminate sail up to a point, but really thrilled with the spinnaker, I had the whole lot this time, and I hope both Peter/John and Strangler/Pippa will admit the boatspeed was pretty good - the handling was not too slick in comparison which is where they gained! That's how I'd like to remember it anyway but it was the first showing so hopefully better is yet to come!

More power, more prizes, more pain, more glory
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John Shelton View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Shelton Quote  Post ReplyReply Direct Link To This Post Posted: 13 May 2010 at 17:27
Is there any interest here in pursuing a rule change to allow different materials? It seems pointless having Mylar with just HMPE reinforcement
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CLINT View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CLINT Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2010 at 14:32
I don't have any real objections. Just wondered what the price comparison is as we try and badge ourselves the alternative class with budget racing being a big part of it. Maybe the sails last longer and this offsets the initial higher outlay?
 
Cheers
 
Clint  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaveChiv Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2010 at 22:51
Hi All,

I think we have some misunderstanding here with regard to the rule format etc. The RYA format is just that, a layout into which each class puts it rules. There is nothing in it which means that classes have the same things.

Equally, there is no need to piggyback off the back of any other class. Decide what you want, and change the rules if necessary. Every class will want something different and there will often be oddities. The Fireball Rules certainly have them and their layout is way out of date.

Tom you quote the first part of the Fireball rule but then how strange of it to insist that reinforcement is woven irrespective of the material in the body of the sail.

I am puzzled by the Scorpion comment because the current published rules say woven material only so that does not allow any film of any type.

When the Hornet rules were re-formatted they were written to reflect the rules in force at the time which had several prohibitions such as aramids and carbon. Hence they are not allowed in the sails now except that the rules were required to have permitted items not prohibitions.

Polyester and HMPE covers all the woven sails and Mylar film and any combination of them. Mylar is a polyester material. HMPE is included because some of the Mylar film sails use Dyneema as the threads. Therefore you are allowed all the materials which you were allowed under the old format of the rules. Yes you can have the Fireball construction of a film sail with woven reinforcement as long as the film and its scrim is of the correct materials.

To sum up, the rules have not changed and the RYA format has had no influence on what was allowed. If you want to move to Aramids (Kevlar) and Carbon in the sails then it is a simple process of changing the class rules. There will be no objection from the RYA if the class has voted in favour.

If you have any queries then just shout but if you want the wording to allow anything then you would change G.3.2(a) to read: The ply fibres are optional. This would allow absolutely anything.

Cheers
David


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John Shelton View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote John Shelton Quote  Post ReplyReply Direct Link To This Post Posted: 17 May 2010 at 15:22
Ah, Mr Chivers, how good of you to drop in
 
My question is whether sails made of laminates similar to Dimension Polyant fit within the current definition. I think not, as those laminates normally include Technora, which is, I think, carbon. But most of the top sailmakers (P&B, Speed, North) offer that option, and speaking from personal experience, it's a good stable cloth, which lasts a long time in a given shape (however, you have to get the shape right to start with!).
Interesting comment about the Scorpions - are their definitions the same as ours? I notice many of the top boats are using Dimension Technora-based laminate sails, so I presume they measure.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaveChiv Quote  Post ReplyReply Direct Link To This Post Posted: 18 May 2010 at 15:43
Hi John,

Old habits - can't really stay away! Always happy to try and help.

Technora is an Aramid so would not be allowed in Hornet sails under the current rules.

The problem is that we would have to know exactly which cloth was being used. I don't know what the sailmakers are actually offering but Dimension Polyant produce variations on a theme. They do a cloth called X-Tech which has Aramid in it but they also do a cloth called X-PLY which is a polyester film with black polyester fibres and that would be perfectly legal. Because the fibres are black people often assume they are carbon.

I think the current rules allow good cloth but as I said before if there is a cloth which would be worth having then lets change the rules.

I see that there are photos of Scorpions with laminated sails and I am aware that their new rules should be out very soon. The current rules say woven only so I assume that there must have been a rule change. I would suggest that the sails with black threads may well be the X-PLY type of material.

Cheers
D
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