Found this on a website :



Forte Reinforced Tubular Structures, Inc.
194 Riverside Ave
New Bedford, MA 02746 508-991-4828
Mailto: Mtdilemma@aol.com


Forte RTS is willing to market in Europe the carbon beams it produces making use of the filament winding technique both for A class and 18HT catamarans. The beams have been engineered by Pete Melvin and are very light and very stiff.
The well known Gunboat, the Javelin 2 of Peter Johnstone, is fitted with RTS Forte beams.


Description: Structural Spars A Class Strikerless ;
Overall diameter 82.55mm in area of attachment
A class Forward beam ; Weight Kg 2,750 ; Price USD 299,72 ex factory
A Class Aft beam ; Weight Kg 1,650 ; Price USD 255,36 ex factory

Description: Structural Spars 18HT Strikerless Forward Beam ;
Overall diameter in the area of attachment 97mm ; Weight Kg 4,100
Description: Structural Spars 18HT Aft beam -
Overall diameter in the area of attachment 95mm ; Weight Kg 2,750

Price for the set: USD 883,28 ex factory

*********

(wouter) as comparison a 95 mm by 2 mm 18HT rearbeam in T6 or T7 aluminium is about 4.0 kg and costs about 100 Euro's = 130 US$ This beam with dolphin striker as mainbeam will be about 7.0 kg. However a big section like that is not need as the mainbeam. You can do it for 6 kg without any noticeable loss of stiffness. With respect to carbon beams such a setup may well be stiffer. That Striker setup does really lead to alot of stiffness in the vertical plane. Note how these weights are all excluding any additional fitted like mastfoot and endplates. The same applies to teh carbon beams. Both sets of beams will therefore come out heavier.


All you F16 sailor please note that you may have carbon beams but you may not glue them to the hulls. Sorry.


Wouter

But if the boat is near to min weight with alum beams, and lets say you save an extra 10lbs off the total weight with carbon beams, you wont be legal anymore.

Correct?

It is something to watch.

Yep Robi,

And then you have to add lead corrector weights to get back up to min weight again.

You have just discovered one of the smart F16 class rules dependencies that limit the attractiveness of expensive parts.

By making alu boats close to min weight we take away much if not all of the benefites of things like carbon beams or masts.

Thus a builder and home builder end up with the situation where they can spend a few 1000's U$ more and still end up with pretty much the same boat. What do you think they will do ?

It is the best answer against an arms race without limiting personal freedom to modify and change a design. Make the gains far too small for the additional costs.

Besides I like nothing better then to see a 100.000 US$ boat getting beat by a 10 years old Timber/Epoxy boat of 10.000 Us$ sailed by a crew that spend his money on holliday time to practice (and enjoying) racing !

Wouter

Good point.
another reason why we all must sail F16's

Now wouldnt that be a perfect world?

You can't save more weight than the things weight to start with. They have not made the material yet that is going to take 10lbs off of what the current F16 boats are made with. 1-2 maybe?

I said 10lbs as an example value.

Matt, Please email me at tbohan@strato.net re: the Blade and entering it in the Sailing World Boat of the Year contest. Thanks. Tim

Hi all,

the interesting thing, with Carbon beams bolted in would be how much stiffer it would be than using the AHPC A class alloy beams I have on Altered. She certainly flexes a bit compared to a Mosquito. I guess having such narrow decks makes for more unsupported beam as compared to a Taipan or Blade, the back beam is 2m. between hulls. And yes the main beam rigged weighs 6kg.

Regards Gary.

Gary,
I am using 80mm with 2mm wall on the Blade prototype and the tortional measurements I have done compared to other boats indicate it is quite stiff.
I am not using high temper beams. I'll pick up some of the stiffer Aluminium beams from AHPC in a couple of weeks.
Given the stiffness I'm getting with the softer beams
you may not get the improvement you want by fitting carbon.
Also I understand they didn't really get the returns from carbon until they started gluing them in.
If you do decide to go carbon please measure the tortional stiffness of your platform before and after.
It would be interesting to quantify the outcome on your platform.

What about the shape of the beams? I noticed Perf. Cats stopped using round aluminium tubes a few years ago, went with the more D shaped tubes so there is a flat surface to attach the hulls to. Can this be done with carbon beams or would it run the price off the charts? I think the real reason you have "wiggle" is the round beams attached to the hulls via two bolts and nothing else, no flat surface to screw it down tight. The guys racing the Tybee on Inter 20's go so far as to add a bedding compound under their beams to glue them to the hulls and keep water from entering through the bolt holes.

Is bedding compound alowed in the F 16's? Are the Taipan beams round or flat on bottom?

I will be honest about it , I fully expect alu beamed F16's to be stiffer to way stiffer than any carbon beamed A-cat.

I refer to the (vertical) stiffness data that was presented on the various boat makes a while back. I know the stiffness data on the F16's as well and also they came out significantly better than Tigers, Nacra F18 and other designs. Personally I believe A-cats are very much hampered by the low minimum class weight. They need to cut down on weight everywhere; this immediately translates into either less stiffness or the use of increasingly more expensive parts. The only real advantage of carbon is it weight savings.

I will give you all a great example :

A 80x2 round carbon tube of 2.5 mtr length weights 2.15 kg and has 100 % stiffness
A 80x2 round alumi. tube of 2.5 mtr length weights 3.39 kg and has 67 % stiffness => weight loss 1.24 kg
A 80x3 round carbon tube of 2.5 mtr length weights 5.09 kg and has 100 % stiffness => weight loss 2.94 kg
A 92x2 round carbon tube of 2.5 mtr length weights 3.90 kg and has 102 % stiffness => weight loss 1.75 kg

So dumb designers increase wall thickness of an alu beam, smart designers increase the outer diameter. Note how dependent stifness is with respect to outer diameter !

An alu beam that is at 67 % stiffness is only 0.5 kg lighter than one that has the same stiffness as the carbon beam. Who of us is willing to pay 700 US$ more for boat that is equally stiff and that is 0.5 - 1 kg lighter overall. That is when there is NO minimum class limit on overall weight. As that would make the whole comparison mute.

Of course this all holds true only when the beamlandings are made strong and stiff enough to transmit this stiffness to the hulls. We know know full well that this is not always the case. I refer to the Blade F18 data when compared to the other F18's. The Blade was almost 4 times stiffer than its nearest F18 rival. Its beams are certianly not 4 times bigger or heavier. I also refer to Jake Kohls experience that het wrote down in a post a few weeks back. His reseated his beams on his F18 so there was a proper and tight fit and immediately got an noticeable increase in stiffness.

Eventually it all comes down to proper designing and proper building technics. Watering at the mouth over carbon is for believers, not for engineers who know a thing or two about the mechnics of materials and structures

And normal sailors must learn to see the A-cats for what they are. An one-eyed king in the land of the blind.

They are so good, as are the Tornado's because 90 % of the builders simply don't give a damn about proper designing a catamaran. They are only interested in profit margins. That is why certain 17 foot singlehanders are build using F18 optimized parts. In some cases they use a cut down F18 mast that by that action is way to stiff and heavy for its new use. Other components like daggerboards are not even adjusted and make the design badly behaved. What do we expect when they are pitted against A-cats that arguable are fully optimized for their use ?

However we must not make the mistake of attributing all the difference in performance to the superior design of the A-cat. Superior designing, yes, but not to the perceived superior design. As good as halve of the difference is caused by the other side not doing his best.

What about the comparison between A-cats among themselfs ?

Well, this is a very difficult area. The A-cats are really extreme in certain import performance ratios. They are also extreme in the class limits. 75 kg for a 18 foot platform is not a whole lot. So here every 0.5 kg counts. Also each year alot of things are changes on the boats. Who is to say that all the speed increase is caused by a single factor like carbon beams ?

Now Carbon has one advantage. It allows beams of similar specs as an alu beam for less weight and a little smaller dimensions. In the A-cats all weight sayings can be put into other components that are very much on the edge as well. For example; and extra layer of glass on the highly loaded points. Their low minimum weight makes changes like these very attractive. The true question how ever is wether such a thing is still attractive when the basic design was already sufficiently reinforced in these area's ? Compare it too double glasses to save energy costs. When you go from single to double glassing the gain is serious, however when going from double glassing to triple glassing the gains are as good as neglectable.

This is exactly where nearly all sailors go wrong in their appreciation of the A-cat setup. They think that when carbon beams are better in the A-cat class that the same gains can be transposed to other classes when they go for carbon beams as well. These guys will all be proven very wrong. And actually the Blade F18 has proven them wrong allready indeed.

I think Altered problems are more related to the fact that he can't increase the outer diameter of his beams OR improve on the design of his beamlandings. Don't you think it is telling that :



The A-cat design from which Altered was made was supposed to be such a superior design right ? How come the alu beamed Mosquito kicks its butt in the stiffness department ? Both use alu beams as far as I can tell so the cause can only be found in the design of the hulls. In the beam landings specifically.

I know the stiffness specs of the Blade F16 and yes that one too beats F18's and Marstrom Tornado by a significant margin. Blade F18 is still better but than again they had the room to improved the beam landings even more. Blade F16 is actually closer to the Blade F18 in stiffness than it is to its nearest rival that is the Mastrom Tornado. Other F18's could not hold a candle next to the Blade F16.

So again it all comes down to a class stimulating proper designing of the platforms.

I haven't seen any stiffness data on A-cats yet but I fully expect them to be inferiour. Those 30 kg less overall weight do hit them very hard. Especially now that A-cats have doen aways with the dolphin strikers. These things do add alot of stiffness to a platform. Sure you make carbon beams stiff enough to be compare to dolphin strikerless beams but only at the expense of adding alot of weight to the beam, thus decreasing any weight advantage you had before.

Gary ?

Would you do us a favour and measure you vertical stiffness of Altered one time ?

You are in the unique situation to answer some questions permanently for us. Mostly because I have data on a very comparable platform to yours. I have thus the opportunity to filter out the contribution of one very specific factor.

Measure it as follows.

Lay your boat up (about level) on 4 saw horses. Two under the very sterns, as close to the sterns as you dare. And two under the bows. Maybe use a waterlevel stick to get them lined up properly. Than ask your friend to lift one bow still the other bow rises of its saw horse as well. Than slightly lower the lifted bow till the other bow just kissed its saw horse again. Now you measure the distance between the lifted bow and its saw horse. That is all, well expect that you need to make sure your bolts are in tight and the tramp is tensioned. Thus making sure that we get the best read out.

Will you do that for us ?

If you prefer you can send the data privately to me. I will use it to learn and maintain the equalness of the class and when requested will keep the supplied data secret.

Wouter

Tim,

You are asking the right questions.

Can it be done with carbon beams. In theory, Yes. Practically, no. In order to get them you have to go for a custom production job with probably hand lay-up and the production of a specialize mold. All adds dinero ! I don't know how much it would cost. Your guess is as good as mine.

Bedding compound is allowed in the F16 glass as long as it doesn't glue the beams into place. You must be able to take the beams off and re-attach them without breaking stuff.

Taipan beams are both square and oval. Of course Oval shaped have sort of the same resistance to wiggling as square ones. Having said this I know from a proper comparison that two perfectly round beams resulted in 60 % flexing when compared to two non-circular beams. So this makes a very potent counter argument.

Now I'm sure that in principle non-circular beams are stiffer to circular ones for the reasons you describe HOWEVER its effect may be dwarfed by the results achieved by other approaches like improved beam landing design. The above named example suggests as much



Wouter

The box/round front beams that Perf. uses now also have a support running inside the tube, so it is more like an I beam, round on the front but flat top and bottom, I would like to see that tested against their old round/hollow beams. I'll bet the new ones are stiffer, and torque flex less, which is why they put them on. They also must be a bit heavier because there is obviously more material there.

The F16 class as an education

This may sound like a weird phrase to begin a post but it is true.

One of the things that make me very proud of this class is that it is so much based on engineering experience. It is not apparent from the class rules but they a fully written on these experiences. Their working core to garantee equality is based on them.

We and most I personally gether data from other classes and the F16 class and re-evaluate the rule set on these. I've done this for 4 years now and we are still very much at the orginal rules set. The rules have not change in any significant way since 2002 and even back then the adjustments (limiting mast height for example) we rather tame.

This class and it class rule do really demand of the sailors that they open their eyes and minds and learn. They will learn that choice of design or cut of sail rather equalizes things than give rise to inequality. That choice of material is only an excuss to mask poor design skills. That a well designed alu mast will beat to crap out of any standard carbon mast. That Carbon hulls are COOL but not any faster on the water. That well designed 12.000 alu platforms put red on the cheeks 13.000 to 20.000 a boat big names in cat business. That sailing skills will overcome any inequality in designs or crewweights. That a competitive spirit is the garanteed way to true competitiveness. That an obsessive focus on equality in design is just another form of unfounded fair as walking in the woods at dark is. The creatures of evil are the make of our own fearful mind much rather can creations of the universe. We'll learn that the enjoyment of sailing comes from being inclusive and welcoming and the joy of improving ones own skills rather than winning 1st spot and excluding everybody who doesn't think the exact same way as you do. We'll learn that high tech boats have weak spots and that when these are exploited to the fullest that their advantages are much much reduced. I hope that a few of you will learn of the discussions that are had on this forum and the data that I and others give.

And I hope or rather trust that the fact that all major components in this class are F16 sailors themselfs will make the class all she can be. Matt doesn't want to race a bad mannered boat himself, his wife simply won't have it. Phill will not design a boat that doesn't sail well in both doublehanded and singlehanded setup, it will not suit his way of sailing it. I won't allow any unacceptable inequality in racing these boats, coz I'm not about to my own Taipan F16 alu beamed and alu masted platform I worked at for over 2 years obsolete ! Tony McKenzie, AHPC and Stealth Marine will not make their carbon components any more expensive than they need to be, it is driving their sales. And so on and so on. He all have very much invested interest in this class and non of us will do anything to upset the balance or to cause any other end result than a large international class with level first in winds racing. In doing so we cover a large area of optimimal designing AND the true importance of sailing skill in relation to design factors.

That in itself is very educational.


Wouter

Tim,

Remember the old Nacra beamlandings with the straps ? Now that was bad. That allowed alot of independent rotation. So yes the new beams are an improvement.

With respecy to the inside webbing. That is only there to prevent the bolts from sqeeshing the top and bottoms sides to one another. That is bad as well. Round tubes however are more resistant to that effect.

I'm quite sure the new beams are seriously better. However what I was trying to say is that we must not make the mistake of thinking that sqaure tubes make a platform better than a round tube platform. There are some very convincing counter arguments to that false transpose of a theoretical case.

A great example it this.

We all feel that 1 kg of lead falls quicker than 1 kg of feathers, however a normal sized cube of 1 kg lead falls slower than a compressed smaller volume of 1 kg feathers. We must always take great care to not uncritically transpose a certain result of a stricktly defined situation into a much more general appreciation of things.

It is unbelievable how often this is done in cat designing.

Wouter

I agree with you Wouter, I was just trying to solve the beam twist problem, not that it is that much of a problem...I never heard anyone come to the beach and say "My beams were twisting way too much..." I doubt you'd ever notice twist anyway.

weezy,
Who is stupid enough to believe the garbage you spew?

You are not a structural engineer, or a materials engineer, or a metalurgical engineer, or an aerospace emgineer,
or an aeronautical engineer or a marine engineer, and yet you have the nerve to critisize REAL engineers and builders
who have more years of experience designing and building boats than you have been walking.

You talk like the f16 class is somehow unique and unlike any other Class in the world, which it is not.
It is just another formula class, except you used the specs of an existing, successful, 16 year old design,
the Taipan 4.9, as the basis for your so-called "new" formula.
And for the hundredth time, the Taipan was originally designed with a spinnaker, long before you ever sailed anything.
The other Formulas had snuffers, self-tackers, curve tracks, raised cross-bars, etc, etc, before the f16.
The blade is just another rip-off of the Flyer design.
The f16 has been anything BUT a leader in design.

Name one single innovation fron the f16 Class.

The only thing unique about the f16 Class is that there is no true class organization.
YOU run it as your own little club.

Feathers falling faster than lead?
In what reality?
It is absolutly impossible to compress feathers into a density higher than lead.
I guess you never read about this experiment a guy did where he dropped two different size and weight cannon balls
off of a building and they both hit the ground at the same time.
His name was Galileo and the building was the Tower of Pisa.
But of course YOU are smarter than him.

You seem to think if keep repeating the same lies over and over again, they will one day become true.
NOT!!!

Ive had a bad day and needed to have a fool stick his tiny head-up.. tag your it..


The F16 was set up by a group of sailors, not just Wouter, across the internet.. Then if you had been around when the private emails were going around you would know this.. Name another class that has been so designed! If you cant name one its a unique class.

Sam the T4.9 is a far better boat than your country has designed and producted yes. Perhaps given a few more decades an American company will get it right.. (Isn't this the reason the F18 and F20 are so stupidly over weight?) But The T 4.9 its not the total basis of the F16 class. Fact is the T4.9 doesn't rate as a true F16.. (which you should know if you read the rules)..

Sure the T 4.9 was designed with a standard kite.. But so was the Yvonne 3 decades earlier.. and the Kittycat (which came out of a skiff class!) and the Manta.. But none were designed with an assy in mind.. The modern Assy was first used on AAMI closely followed by the one on the inventors hull. Any boat using an assy is ripping off brilliant Aussie skiff technology..

Self tackers were used on skiffs in the 60s.. So any class using them is again ripping off brilliant Aussie skiff technology..
Curved tracks were being used before any Formula class true.. I know skiffs had them in the 50s..

Phill can answer if the Blade is a Flyer design.. But then Bill Roberts has stated he was the first designer to use a wave piercer hull shape on cats.. So that would make the Flyer a Supercat ripoff. May I point out F. Bethwaite tinkered with wave piercers. So maybe the whole flyer design is really ripping off is just another brilliant skiffies idea.

I would point out my "Thing" wasn't based on the flyer design.. Proudly and unashamedly based on true blue skiff technology with a twist. Is that unique?

Sam why dont you name an innovation you think is unique? (One not based on skiff technology!~) Fact is nothing I have seen in the past 20 years is unique.. Just a refinement of a past design..

Apart from the F18HT all the other F classes are fat and heavy.. Yes the F16 is a little overweight in my pinion but required as we wanted to encourage home builders.. But it is not in the obesity league as the F18/F20.

It makes one wonder when three of use could pick up my old eighteen and walk down into the water carrying her.. She was much more of a machine than your beloved F18/F20 class.. She was lighter stronger wider and carried far more stress than the poorly build holes in the water you worship..

Finall Sam, why not stop taking shots at the F16 go ask the US based manufacturers to lift their game to Aussie and Kiwi standards..

Stewart.. (end of rant and takes tongue out of cheek and now can go play with the dog)

Stewart,
I make no apologies for the Blade being a wave piercer.
It is.
It was designed through literally hundreds of hours of building and testing. Possibly Sam can design a boat on the back of a coatser or rip it off a photograph but I can't.
Build, test, change, build and test.
At least only having to build and test 1/4 size models leading up to the full size prototype helped a bit.

Sam,
Once again I would like to thank you for your constructive input.

Seltacking jib were fitted to traditional Dutch working boats from the 1800-1900 era. That is a good 150 years ago. Actually the principle is much the same with a larg pully block sweeping the foredeck. Multihulls ? A 2000-3000 year old polynesian invention ? And the wave-piercer hull is remarkably similar to 1994 Dart Hawk, that is BEFORE Eigner came out with the German flyer.

Like a wise man said, better to well stolen then badly designed.

Wouter