Regarding foils on Tornados: According to Seahorse (british racing magazine), Marstrøm are tinkering with a easy replacement kit for replacing the centerboards with high aspect ratio daggerboards.

The class would of course have to approve with the usual 2/3

Kevin: It is always interresting to hear about operations like yours. Building your own autoclave is awesome !

I believe that William Sunnocks has a set for his UK T.

As for the Carbon T, my views are :

1, It is NOT a carbon Tornado per se...Its a Carbon 20 Foot cat that happens to be 10 foot wide and look like a Tornado.
2, If you want to race it, so be it - If you were Euroupe based, it would be measured and allocated a Handicap based on the measurements. No problem.

Basket Case,
I have not built an entire boat yet using this material. There were two hurdles to cross. First the cost of Nomex is steep for an amatuer builder. But I found a guy with crates of surplus aerospace honeycomb selling for less than 1/10 retail cost. Needless to say I scooped up over a thousand square feet of core. The second hurdle is difficulty in building tooling the size of a boat hull to process the prepreg/honeycomb material. For builders like Marstrom the tools are a major capital investment. I have a mostly finished F-18 mold but ran into difficulties with porosity of the mold. This can be cured but I am taking a break from the project until the frustration level dies doun and interest picks back up. By the way the, mold has over 600 lbs of glass reinforcement, is over two inches thick, and uses epoxy that can resist 450 degrees heat. It's a very hard thing to make! I have built lots of stuff with prepreg composites and have those techniques down pretty well.

Kevin

****! In order to head off another frenzy of replies, let me state I understand your class rules and why you can't switch materials without making everyone's existing boat obsolete. Not advocating that - just making a point about unintended effects of rules. These issues have been part of the sailing sport since 1870s.

Kevin

Kevin: That is a very interresting point you make with regards to the price of the boat.
I never tough about the tooling cost, and assumed it was materials and working hours + fittings that made the boat expensive.

That would explain why Gøran Marstrøm broke down sobbing when he accidentaly broke one of his moulds while moving it into the autoclave (this was while Marstrøm was quite new in the market)..

With the current production methods and weight limit the Tornado's really last a long time. Would you say that they are overbuildt and that a skilled homebuilder can build as stiff and lasting boat as Marstrøm in his garage within the class rules ?
(I'm not out 'trolling' here, just want to hear your opinion)

Rolf

Hi Macca,
The proof of speed is in the demonstration. I don't see anything as fast as the Tornado in this latest crop of "new designs". Look at Portsmouth Numbers for an unbiased source of relative boat speeds. The point is that good engineering and good design do not get old. I have been a part of catamaran design and performance for about 25 years. Over that period the only boat that was ever issued a PN lower than the Tornado was the Supercat 20. There was a time when the standard SC20 was 62 and the SC20TR was 60 while the Tornado was 64. These are the only 20ft boats to ever be rated faster than the Tornado. Today there is the ARC22 which is the SC20TR with the hull stretched 2ft in the front end; same mast and rig and boards and rudders as the SC20TR. Today that boat has a PN 2.7% lower than the Tornado with spinnaker. This PN diference also has within it the fact that the ARC22 is sailed by good/average sailors and the Tornado, best data, is sailed by Olympic caliber sailors. That effect itself could easily cut the PN difference in half.
So Macca, there aren't many new design ideas out there waiting to be incorporated into a Tornado beater. I remember when the TheMightyHobie18 first came out and it was touted to be a Tornado beater. What a puff of hot air that was. The M20 is 140 pounds lighter in weight than the Tornado with a more efficient sail plan and high aspect ratio boards and rudders and the best it can do is sail even with a well sailed Tornado. Isn't that 140 pound weight reduction of the M20 worth something??? What's going on here? What's wrong? I guess good boat design and good engineering just doesn't get old. Maybe it is something like a good piece of art work where form is function.
Bill

kevin,
i have heard that the guys building open 60 monos are building the molds from carbon. i am not quite sure why they do this. pretty sure it could be done with a good epoxy and lots of 10 oz.
there was an interesting story in pro boatbuilder a few years ago by henry eliot. he was building an a class mold and found it porous. i think he drew vacuum on the tool side as he applied more epoxy to the back side of the tool. this seamed to work. oh ya, he bagged the tool laminates on the the plug.
i would like to pick your brain a bit more, later. in the next few weeks i am going to be starting work on the new open 60, spirit of canada.
thanx.
keith

Basket,
They build the molds from carbon so the thermal expansion of the mold will exactly hatch the part (hull) being molded. This is not an issue at meduim temps but can become important for 350 degree cure prepreg. It is depends on mold shape - a complex shape that has reverse curves and acute angles can produce residual stresses when cooling down. These can damage the mold or part or cause the part to get stuck. shouldn't be a problem for a simply curved mold like a hull half.

Kevin

Kevin

thats what i was thinking, but it still comes down to the resin matrix. if the tg on the resin is high enough, there should be no problem. you can also get a low temp prepreg that cures at about 160.