Actually you said:



Busted doing what exactly? stating a fact?

Wouter you have continually attacked my credibility and knowledge of matters that I have extensive aquired knowledge.

Macca,

You are a well known and well respected sailor, who until a few days ago had only posted in the F16 forum a few times,

In fact 17 posts (I think, I may have slightly miss counted) since 19th Dec 2005, until 10 Feb 2008.

Over the next few days, you come into the F16 forum and post 52 posts of a total of 75;

Now, I agree that you and Wouter have had a bit of a slanging match about 3DL sails and seams and it appears some harsh things have been said via PM. Perhaps time it's to agree with Wouter that it might be a good idea if you don't play in the same bit of the playground.

But you have also been hammering along about the same thing (the weight of the F16) and people who sail the boat keep replying that they are quite happy with the boat at the weight it is.


Now, I think it is time that the current owners of F16’s to agree to disagree with you.

You want the F16 to get all lardy and difficult to drag around the boat park by us single handers (does your vision of the F16 even contain the single handed option?)


We, the current owners, whom have the right to vote on class issues, want the all up weight to stay the same.


time to call it to an end, you want one thing, the owners want something else

being a troll and being a reasonable sailor aren't mutually exclusive...

If I have to be a muppet then I want to be Beaker!!!

You gotta to love a puppet that can't help but blow himself up!!!

Allthough, one has to love the shrimp too.

lol

Actually Tony, I think you are fundamentally wrong in two lines of reasoning.





That is the same as arguing that spinnakers don't use "broad seaming" because here the edges are now glued together rather then stitched when of course the identically designed spi's of 8 years ago and older did use "broad seaming" as they were the last ones to use stitching.

Incidentily, there are are many examples of descriptions becoming to include more general situations then the one that gave them their meaning initially. For example welding. Was defined initially only for steel, but now includes all kinds of other metals and also plastics. In the latter case the proces doing the joining is significantly different from metal welding, although both methods achieve fixation by locally smelting parts by heating.

Interestingly enough a weld on a thin sheet of plastic is called a seam again. Think of any inflatable rubber boats were many people easily say things like : "The skin ruptured on the SEAM". Your argument would even have it that the use of the word SKIN is wrong here as only animals have skins. Another example of an identifier covering more and more general situations AND having been accepted as such by many many many years.

The core intent of broad seaming is to introduce more cloth locally where a flat sheet has to cover a longer distance from egde to egde when forced into a 3D shape. The usage of stichting is not a key part of this, it is just a way of fixing the panels together out of a series of alternatives. Using a different method of fixation like glueing doesn't chance in any way the intent and result of broad seaming. In that sense Rolf initially used this identifier and he was totally right in doing so.

Actually, this practical reason is the same as shaping as only a shaped sheet of material can follow a 3D surface in a smooth manner. So shaping was the intent here because of the practical need to have it follow a 3D surface smoothly and it was done by a method that as good as everybody calls .... .

Hence my earlier argument, does a rose by any other name smell less sweet.






Again, the erronous corellation is made between something being expensive and something being more performant.

To this reasoning I gave the counterexample of a kilogram of aluminium (or lead) weighting the same as a kilogram of gold. The fact that gold is much more expensive does not in any way make it perform better or prefered or even a precursor to an arms race.

In fact both gold and lead have very similar ballastic properties, yet we all shoot lead at olympic contests and not with golden slugs ! That is without the gun classes having any rules against the use of gold in slugs.

The F16 rules work in the same manner. Mister Bartelli can have his beams made of gold or platinum if he wants too, just as his shower taps are, but when staying within the set of F16 rules these beams won't preform any better then cheap aluminium ones. Now, Mr Bartelli is not stupid and so he won't even try. If any other fool does then the only result he will achieve is wasting alot of his money.


Additionally, some people are great sailors but that does not in any way make them equally skilled or knowlegdable engineers or scientists. The same works in reverse of which I'm a good example myself. You will not see Micheal Schumacher telling his engineers how to do their job and not be laughed out of the stable. Making suggestions is all fine, but persisting at making obvious fawlty suggestions is making a fool out of oneself.

Wouter

Gohh, dont feed the troll Wouter, or we will never see the end of this muppet infestation. He has no credibility left so let him die from lack of recognition.

Wouter,

Lets stick to the 3DL question. Broadseams or not?

I'm replying to Tony, Rolf, and not Macca.

Tony can not by classified as a troll by a long shot.

Wouter

Aww come on Wouter, I still want to play!

You know how to make me go away, just show me the Broadseams in a 3DL sail and I will never return to the F16 forum <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

If I'm gonna be a muppet I might as well have an avatar to match <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

Wouter:
You got me on the spi's glueing thing!
I guess the definition of the word "seam" depends of the context of where it is used.
This is what the dictionary says about it:
"Seam: joint consisting of a line formed by joining two pieces ".
For me there is no further debate on that word, that's final.

From the information I gathered it seems (no pun intended) that the shape of a panel used in a 3DL sail is not fundamental to the shape of the sail as a finished product, as the 3D mould is.
In theory there could be a 1cm gap between the panels and it would still work as a sail (a crappy one yes, but still a sail).

There is overlap between both manufacturing methods that causes confusion and debate but I am convinced they are fundamentally different.

Anyway, I would not refer to a 3DL sail as a "panel sail" as I would a regular broadseamed sail (eg F18 main).


About the rest of your post:
If I win the lottery I will get myself a gold F16! (should make for a nice insurance policy!).
I personally think that having stricter rules would leave less open to interpretation, there are still a few wars running about what a particular book says on something.
If for example aluminum is the best material for a mast, why not put that in the rules?
Maybe I am just either too thick or practical to understand these things, I will let you decide which it is <img src="http://www.catsailor.com/forums/images/graemlins/blush.gif" alt="" />

Actually even a perfectly flat (hard board) panel can work as a sail, the only difference being that it is less efficient then a shaped sail. So that criterium, being able to work as a sail, is not very useful.


Also, the shape of the panel (however you define that) is absolutely vital in determining the final shape of the finished product. How can I show this to you without having to use more arguing ?

This might work !

Think of the similarities between 3D sailmaking and the tortured ply method of building hulls. Of course the latter is also know as "stitch and glue building" but that is a sidetrack. Go to this link to see the 3D mould and the panel shapes :

http://www.catsailor.com/forums/sho...er=132859&Main=132040#Post132859

Note the similarities between 3D sailmaking using a 3D mould and the creation of these F12 hulls using again a 3D mould. Actually in principle there is no difference.

Now there are two mind experiments for you :

-1- You try to get flat panels to sit right in that mould without shaping the edges of the panels.

-2- You try to flatten any combination of two or more shaped panels that have been joined and taken from the mould.


You can't do the first without significantly curved egdes (broad seaming)

You can't do the second without rupturing or even totally distroying the connection at the seams.

The mould is only there to keep the panels properly curved and positioned relative to eachtother to allow the bonding (seams) to be created. After the bond has set (is finished) the mould can be taken away and the the internal material forces around the seams will maintain the overall 3D shape.

With regular sailmaking the sections are just pinned (or glued) together at the seam and bundled up while being moved under the sewing machine, much like our mothers did with our clothing ! With 3D sail making the sections are pinned over a 3D mould while being glued into place. That is not enough to qualify as a fundamental difference (between 3D and regular sailmaking).



This is the way things are when making 3D shapes from any 2D "ingredients"; as all sailmakers do because the cloth and monofilm suppliers all produce flat sheets/films; possibly bend over rolls or folded up for easy transportation.

The only way out of this stranglehold is 3D polymerisation (similar to casting metals) OR reshaping the panels by heating them and resetting the material structure to a new overall shape (similar to forging metals).

The first implies that the material is directly created chemcially in a 3D mould of the sail. As of yet there are no such machines and it is extremely unlikely that such a machine will ever be build for a sailboat sail (notice the singular as any you will need a new machine for every new sail design). Of course such machines are created for some mass produced elements like automobile parts and electrical wall outlets.

The second method has the problem of not being fundamentally different for thin sheets; look at it this way. Forging a thin sheet of material to a reflect a different contour is no different then simply cutting the resulting contour from an unforged piece of thin sheet. Different paths, yet the same final results. Of course forging pastics runs into several other problems that make it much less attractive then it is for metals. A very large portion of plastics don't take well to heating for example.

Wouter

Forget part of your post sorry,




The mast is actually one of the few elements were the choice of material is rather important.

This has mainly to do with the differences in how mast is produced. Aluminium masts are only viable when extruded and this leads to a constant stiffness behaviour. Carbon masts can of course be layed up using locally different distributions and directions.

Nobody is saying that aluminium is the best material for masts, nor that any other material is.

So how do we square this situation with equality under F16 class rules ?

First we must note that at no single instant does the F16 class rules rule on details. This was a fundamental choice we made at the beginning. The rule makers did not presume to understand what the future might bring. Something that is expensive today could be cheap tomorrow and visa versa. Basing class rules on such fluctuating conditions would only create future problems that are best avoided. The decision was made to ONLY rule on abstract design specifications that would remain invariant under changing societal conditions. Laws of physics are one such invariant abstraction. Hence the F16 class rules rule on dimensions and shapes but not on materials. In that respect we are fundamentally different from the F18 class.

In order to substantiate the claim that "Something that is expensive today could be cheap tomorrow" I present the following example.

For about a good century, the Royal French court (as others) dinned of aluminium plates using aluminium cutlery instead of golden versions as was the custom before the discovery of aluminium. This was because at that time Aluminium was more expensive as Gold. The electrolyse method of converting Bauxiet (Aluminium ore) to pure aluminium hadn't been discovered yet and the metal had to be seperated using a difficult chemical method. And that made it more expensive then Gold. It was also considered a magical metal for being so much lighter then any other metals known and didn't corrode. Right after the discovery of the other seperation method, aluminium became so cheap and easily accessible that we now only consider it as dining equipment fit for a camping.

Similar reversals of fortune has happened in various field many times over the last 150 years. Who is not to say that carbon will become cheaper then aluminium somewhere down the line ? Or that a new material is discovered that replaces both ? Kevlar has already largely replaced carbon in hull construction because of economic shortages of carbon caused by booming airliner production.

Indeed, ruling on details such which materials can be used is not smart at all.

So limited by this fundamental choice we simply moved to equalize the masts made from any material to eachother. This resulted in the tipweight rule, F16 class rule 1.4.5 , adressing the enertia difference between masts of different overall weight.

That left only the inequality in local stiffness to be adressed. This "problem" was solved when it was found that an extruded alumnium mast, with constant cross section, could be fine-tuned locally in stiffness using a simple, lightweight and inexpensive method. A method much more suited to mass production then full carbon masts.

As it turns out now the difference between alu and carbon mast has not been found to be such that it was needed to further develop this new approach and it is in the refrigerator for now.

Interestingly, I pioneered the basic idea and worked on this mast design and it was likely to go onto the Aussie Blade F16. It is currently on hold as at this time not a large enough economic need is felt to implement it.

I won't publicize the details of this concept as it has some interesting economic potential. Also it can be used in the F18 class right now without it being easily spotted or be in clear breach of any F18 class rules. Additionally, this "concept" can be "retrofitted" to existing aluminium masts. So we can afford to wait this one out and see if the need to do so every arises.


Of course we also had a class vote on mast material back in 2002 and there is was afirmed that masts made of any material (specifically carbon) should be allowed. So as such it is a feature of the F16 class rather then a loophole that needs to be closed.


Summerizing :

-1- The F16 rules don't regulate on any materials due to a clear and fundamental line of reasoning
-2- Other rules are present in the F16 ruleset to equalize masts made of different materials
-3- Constant cross sectional masts as they are now are not making use of their full potential yet.
-4- The difference in performance between masts of different materials has not been found to lead to significant inequalities on the race course yet.
-5- The F16 class membership explicetly voted to allow masts made from different materials and in specific carbon.

Wouter

Still no sign of that Broadseam in a 3DL sail though...

Gee Wouter, you have time enough to write two essay's on your various theory's but can't find the time to prove your claim that a 3DL sail has Broadseams?

How about we excuse you from Essay duty whilst you reseach and obtain proof of the Broadseams in 3DL <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

This is becoming quite tedious-
I looked up the definition of broad seeming as anyone could.

"Broad seeming is when you build curvature into the sail surface, you do this by building the sail in panels, (see link above), only instead of a straight seam, that produces a flat sail, you fuse the panels together on a very, very slight curve.
Too much curve in a sail that is broad seamed results in a sail that will keep that shallow "bowl" shape even on the wrong tack, unless the wind is strong enough to punch it in."

Now whether this helps or not I don't know nor do I care but as to date this conversation seems to be about the definition of an English word when one person's first language is not English.

How about you two either get your own forum or call it half time and continue this conversation in Dutch and leave the rest of us in peace.

BTW:- If this has already been covered I still don't care. Instead of working on my new boat I think I'll go ride my bike.

I think Wouter perfectly understands the definitions,

His contention that the mylar film used in a 3DL sail consists of Broadseams, or any other seam with a sail shaping purpose is very well explained and shows that he clearly understands what he is saying.

The only problem with his claims are that they're just plain wrong.

Would it be beneficial to hold a vote of contributors and observers opinions on this? I suggest that before doing so voters be compelled to read North Sails' information on the process and structure of 3DL sails.
My understanding of this is that the mylar film panel overlap and shape is of little consequence to the form of the sail shape. The film acts as a carrier for the adhesive (pre-consolidation) and north sails quote the 'ADHESIVE' as being responsible for the bonding of the structural fibres. During consolidation under heat and pressure the film will deform and mould itself around the structural fibres and CONTINUOUS ADHESIVE MATRIX. The shape is dictated by the mould and the structure dictated by the adhesive matrix securing the structural fibres. Therefore, the shape is not dictated by the mylar panel seam shape so is not broadseaming. Forget any previous analogy with tortured ply as you would be comparing a pre-consolidated structural material (the plywood) where shape is paramount with a non-structural material(mylar film)where the film overlap seam shape is incidental.
Just to highlight the difference with broadseaming, I have Sobstadt genesis sails. These are panels which are broadseamed, as the structural panels (non-continuous fibre tows)are shaped at consolidated panel joints (seams) which are glued to each other to impart shape.
Anyone care to start a poll to canvas general opinion on this?

Cheshirecatman

Yet North state that they use "Mylar sections joined together with modest shaping to lie reasonably smoothly over the 3D surface of the mold". So is the argument here (and I agree with Phill that it's been pretty tedious to watch) over whether the shape of the seams dictates the final shape or only enables it?