Class rule official interpretation 2 - rule C.9.7

Use this section to ask any questions over current class rules or to make suggestions over new rules that may be worthy of consideration.
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Class rule official interpretation 2 - rule C.9.7

Postby paul manning » Mon Sep 05, 2016 3:25 pm

Rule C.9.7 STANDING RIGGING (a) MODIFICATION, MAINTENANCE AND REPAIR
(4) Standing rigging may be replaced and shall comply with the following:

(i) Construction shall be 1 x 19 stainless steel wire rope.
(ii) The forestay, shrouds and lower shrouds shall be of a minimum diameter of 2.9mm and a maximum diameter of 3.1mm.

The class IM confirms that dyform wire does not comply with the class rules and is not class legal
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Re: Class rule official interpretation 2 - rule C.9.7

Postby duchonic » Tue Sep 06, 2016 7:22 am

49er class rules 2016:
C.9.1 (h) blabla,
(i) Construction shall be 1x7 stainless steel wire rope
blabla

According to serveral sources the 49ers
were sailing with dyform at rio olympics.

Don't know the hassle about this issue.
Specially if i see that the professionals
really don't care about this one!

Maybe put this issue in the annual survey and let the sailors decide!

see you,
SUI 470

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Re: Class rule official interpretation 2 - rule C.9.7

Postby skiffer » Tue Sep 06, 2016 9:22 am

duchonic wrote:49er class rules 2016:
Don't know the hassle about this issue.
Specially if i see that the professionals
really don't care about this one!


Why would you want to use dyform?

It is more expensive to buy, it is fragile as it can be damaged in transit, it is less available and worst of all if you hit it during a pitch pole it will cut you up ...

Seems to me dyform offers no advantage why would we want to allow this to be used in the class?

We all have the same stuff, why would we want to allow people to change to a more expensive and worse option? In fact why would anyone want to use this stuff?

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Re: Class rule official interpretation 2 - rule C.9.7

Postby duchonic » Tue Sep 06, 2016 9:53 am

I wanted to start a objectiv conversation about this subject.
Maybe i better go sailing instead.
See you

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Re: Class rule official interpretation 2 - rule C.9.7

Postby skiffer » Tue Sep 06, 2016 11:19 am

duchonic wrote:I wanted to start a objectiv conversation about this subject.
Maybe i better go sailing instead.
See you


I have given you my reasons why I don't think dyform is a good idea.

Perhaps you could tell me why you think it should be permitted?

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Re: Class rule official interpretation 2 - rule C.9.7

Postby Daniel Henderson » Tue Sep 06, 2016 4:53 pm

ooo this sounds heated. I dont think there is any advantage with dyform. I think high end dyneema is an advantage purely on cost and ease to change.
GBR557

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Re: Class rule official interpretation 2 - rule C.9.7

Postby skiffer » Tue Sep 06, 2016 5:10 pm

Daniel Henderson wrote:I dont think there is any advantage with dyform.


No heat from Skiffer ... just asking what the advantages of dyform are ??? I can only see disadvantages. :( you seem to agree ...

Daniel Henderson wrote:I think high end dyneema is an advantage purely on cost and ease to change.


Isn't that rope?

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Re: Class rule official interpretation 2 - rule C.9.7

Postby GER170 » Tue Sep 06, 2016 5:20 pm

Standard literature suggests that dyform is a higher performance product. 30% higher breaking strength, 25% lower Stretch (for 3mm)
http://www.rigshop.com/site_pages/produ ... /wire.html

btw, dyform seems to be 1x7 in sizes up to 4mm and 1x19 above that.

I think we should also seperate the different stays that we have on the boat: shroud, forestay and lowers. The differing properties of Dyform from Standard 1x19 (and dyneema for that matter) have a different effekt in each location.

@Nicolas,
are you suggesting to allow the use to make peoples lifes easier as some shop only carry either 1x19 or dyform?
Or is there another reason?
Which stays are you suggesting it for?

@Dan, have you tried dyneema on the MPS? Which stay would you put it on?
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Re: Class rule official interpretation 2 - rule C.9.7

Postby paul manning » Tue Sep 06, 2016 5:49 pm

1x7 is dyform wire, so the 49er class sailing at the Olympics are all complying with their own specific class rule because they are only allowed to use 1x7 dyform.
Also, as all rigging must be bought from the builders and comes with an authentication label the 49er class doesn't have the problem.
If we rememember our class also required all sailors to buy all rigging from the builder but owners felt this was not practical. The class rules were changed accordingly.
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Re: Class rule official interpretation 2 - rule C.9.7

Postby paul manning » Tue Sep 06, 2016 5:55 pm

I think it's worth getting this into a bit of perspective.

Regarding the elongation differences between 1x19 wire and dyform wire of 3mm diameter is worth doing the sums. Note, on the lowers, the difference when loaded past the breaking load of the original 2.5mm wire is less than 2mm...
So in a normal sailing situation you are unlikely to see a difference in extension of more than 1-1.5mm
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Re: Class rule official interpretation 2 - rule C.9.7

Postby sutho » Wed Sep 07, 2016 3:53 am

Hi All,

I tried dyform back when we were breaking 2.5mm lowers it worked and did not break. The only difference was I had to change to slightly less tension because dyform stretched less. As Paul indicates it was pretty much the same as when we went to 3mm lowers - less stretch & breakage. As I recall the reason I went to dyform was that I could not get 2.5mm 1x19 its easier to get dyform in good boat shops. My conclusion is it really does not matter in terms of performance, or cost if we use either, its just one of those rules from an era when it did matter.

I think Dan and Iver opened the subject of Dynema, certainly to me it would make sense and reduce cost to allow the use of ropes such as Dynema or the like for the standing rigging. The forestay to me would be the best candidate, and it would save us replacing them so often due to corrosion on the section for the boat breaker. It would also allow us to clean up the forestay of various pipes, tapes etc that protect the boat breaker and adjuster.

Probably the best solution for cost and practicality is make rigging open, for rope or wire, its not going to make the boats faster.

I know other classes are using carbon rod rigging but I suspect the cost of that right now means we should not open up to that extent yet.

Chris Sutherland AUS 511 (looking forward to summer sailing in 3 weeks)

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Re: Class rule official interpretation 2 - rule C.9.7

Postby paul manning » Wed Sep 07, 2016 5:38 pm

Following the discussion to date, I've done a bit of research today, please see below

Retail cost
3mm Dyform £3.28/m
3mm 1x19 £1.80/m

PBO forestay for Int. Moth £91.00
1x19 forestay for Musto Skiff £44.95

I've spoken with one of the sponsored Int. Moth sailors that I work with and they use dyneema, but the boats have less rig tension, the rope creeps (even SK90 pre-stretch), so you have to adjust it and it wears out quite quickly.
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Re: Class rule official interpretation 2 - rule C.9.7

Postby duchonic » Wed Sep 07, 2016 6:28 pm

Let's do some math with the lowers (and it's just about the lowers!):

1 x turnbuckle blue wave for low shrouds = 104£
2 x 1.8£ = 3.6£ -> total 107.6£ (the cheap solution)
2 x 3.28 = 6.56£ -> total 110.56£ (the expensive solution)

So you save 2.6% of your money just for material.
Going for the cheap solution on both lowers saves you a beer (5.92£)

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Re: Class rule official interpretation 2 - rule C.9.7

Postby duchonic » Wed Sep 07, 2016 6:50 pm

paul manning wrote:PBO forestay for Int. Moth £91.00
1x19 forestay for Musto Skiff £44.95


You compare cable weight less than 20g and diameter of 1.8mm
to cable weight of 200g and 3mm!

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Re: Class rule official interpretation 2 - rule C.9.7

Postby duchonic » Wed Sep 07, 2016 6:53 pm

I'm out, heading for Dongo, Musto sailing!
Have a nice week.


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