Folks,
Just wondering if the profile of the Tornado mast was changed when they went to carbon.
I'd be interested in the the major and minor axis dimensions of each mast.

Just curious as going carbon was a good opportunity to take a careful look atthe profile.

Also any pics of the carbon mast.
I hear they are a work of art.

Regards,
Phill

Ok- I found what I was after.
Minor axis 72-73mm and Major axis 134 - 135.5mm

From this it looks like they kept the same profile.

mast base

That's correct...no changes in profile for the carbon stick. But it is much lighter, stiffer and better controlled as far as flex characteristics. The spreader arms look like airfoils in shape and the diamonds are rod rigging, not stranded cable.

And the bend properties between masts in static tests are really close (les than 5mm variance) but in dynamic use... big differences. <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" />

What do you mean with "dynamic"?
/håkan

Dynamic, like in use.

The mast bend on the test bench shows them to be very similar. I think the first 200 masts were within 5mm bend with 50kg hanging off them.

But there are some big differences in the way the masts react when sailing. The differences are not as big as we had with the alloy masts but there are some marked differences between masts.

Some of us are less surprised about this then others.

Wouter

The move to carbon masts made the situation better for the sailors compared to the aluminium mast, or? If I have correct information the carbon mast is lighter, stronger and has less differances between each mast.

But the sad thing is that the this is the last Tornado Worlds with pro sailors....

/hakan

I think you would be in a very small minority...

It's possible to order a Finn mast with less than 1mm variance in bend from spec in both static and dynamic use.

So why exactly is a Tornado mast different to the finn mast in that regard?

Well, let's take a quick look:


Seems to me that the Finn mast is a circular, maybe tapered pole with one small sail on a boat with low amount of beam to counter heeling forces. Should be a lot easier to engineer flex characteristics within a given range than a 30', teardrop section with a taper and diamonds on a 10' beam double trapped cat.

When you introduce fittings for the spreaders and diamond hounds...there will be variation in their precise location. This likely accounts for some of the differences between masts. I've also heard the rod rigging of the diamonds is not always uniform & consistant in size between batches...that's another source of variation. Marstrom also changes the type of cloth being used on the masts at some point.

So what's the problem with some variation in the carbon sticks, dynamic or otherwise? You've stated the range is less than with alloy...and that was the whole point in the first place.

The original proposal was to have a one design mast and that the masts were to be identical (or as close as possible) the expectation was that the scenario the Finns enjoy would occur. A finn sailor can order from one of several builders a mast with exact bend properties and get it.

A Finn mast is actually harder to build with those properties than a T mast. The Finn mast is not circular as you say, but is much more wing like than a T mast or even a A class mast.

Finn sails are amongst the most carefully built sails in the world, luff curve alterations of 1/2mm are common. Having less righting moment actually makes the mast more critical and getting the bend right even harder to do.

How do I know this? Well I coached the Aus Finn team...

The problem with variations in the carbon masts is that it put us in the same spot we were in with the alloy masts! We used to have different mainsails for different alloy masts and now we still have to make different sails for carbon masts.... It would have been much better to be able to take sails to each boat (masts) and have no difference between them. Also would have been cheaper....

Macca,

So are you saying that Marstrom quality control is not up to the Job?

I'm saying that the masts behave in a way that was not expected.

By whom ?

Any properly educated engineer is taught or knows from experience that producing perfectly identical components by intent is a fallicy. Especially when components are very elongated, complex or even bulky.

The Tornado class has been on a OD-design fallicy ride. The "minority" has been on recieving end of scorn for a long time, but I bring back to memory the common industry solution to this problem as was presented to all when the Tornado carbon masts were proposed.

The sprockets used in rear axle differential coupling in cars and trucks are component that require to be very accurately produced for proper operation (low wear). The general geometric shape is such that this is even harder to achieve then with normal sprockets. Hard = prohibitively expensive.

Solution : By understanding that variations in the end product are statistical in nature (as all variations in real life are) one can produce a large number of these sprockets using pretty inaccurate means and then just measure all of them and combine complementary parts into the finished product. Here the inaccuracy in one direction is offset by an equal and opposing inaccuracy of the other part.

This way highly accurate finished products are made using pretty cheaply produced and relatively inaccurate basic components.

Working on this principle it is actually CHEAPER, to have a batch of 40 masts made and have these measured and have one selected to fit a given sail best then to try to produce a sufficiently accurate carbon mast in one try for the same given sail.

This was the way of doing things when Alu masts were still used and it appears that the same procedure is best followed with the new carbon masts as well.

This needs not be a bad thing either. Best any producer can do is just produce a batch of masts and measure them all and have each crew bring a sail (that will all have significant variations as well) and have them select the best mast from the batch. Due to the sail variations it is high probable that each crew will favour a different mast and in the end a very high percentage of the batch of masts will be sold. The remaining masts can then be sold at discount prices to recreational sailors thus earning back the investments.

Industry does this in an overwhelming manner where the components can not be adjusted after they are produced for technical reasons or economic reasons.

Why did anybody believe that the Tornado masts would ever be any different in this respect ?

Wouter

Thanks,

I will let the Finn mast builder know they have been wasting their time and they should in fact be mass producing masts and then just sort through them to find the right one....

Or how about they continue to build masts to spec and save themselves a whole heap of time and money??

You haven't read my post properly. It is actually CHEAPER and quicker for industry to NOT do things in that way.

Just producing masts and pair them up against normal variations found in the other parts, like sails, is the cheaper and easier route.

And it is also the way competitive laser sailor approach the problem for a fraction of the cost.

Actually, when using a sufficiently large "population" (statistical term) you can achieve practically identical combo's. Something you can not achieve EVER in the way the Finn class does it.

That is just the way things are irrespectibally whether the Finn class maybe considered smart of dumb in this respect.

Wouter

Macca

please don't goad the Wouter - we will have to up his medication.

I know it is hard to do for some here, but doesn't anybody entertain the thought that "Wouter without medication" could bloody well be right in these matters ?

A selection of the noteworthy cases involve the LR2 A-cat performance, full foiling (C-class) catamarans, Fosset/playstation short lived round the world record and their snubbing of Jules Verne organisation and the French, 16 footers performing on a par with F18's.

And now we can add the Tornado carbon mast to the larger listing as well.

Does anybody recognize a trend ? <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

You guys can keep stumbling about in the dark if your love for hating that bloody Wouter demands it but you will only end up hurting your own toes, knees and chins.

Wouter

DAMN IT, HE'S RIGHT!

All Hail the 'WOUT"!!! <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />