Why is the Tornado so fast, its an old design yet still manages to beat the competition.

Whats so good about about it? is it just that it attracts the best crew being an olympic boat, or is it something about the boat itself, length, beam, sail plan etc.?

Gareth

In my opinion:

1: 30 years of refinement of the platform
2: Olympic-class development of sails
3: Olympic-class crews
4: Olympic-class research on how to sail the boat fast

No doubt, many boats could have been as fast or faster, but they have not been subject to the same intense research as the T. It doesn't hurt that the design was fast from the start as well, even if there are faster hull shapes today. The 10 foot beam is a 'must' when the wind increases.
I think it could have been even faster with daggerboards instead of centerboards.

Edit: A more interesting question for me is "what could make the Tornado faster/better"

Yep, I would agree with all that.

Some expirements with daggers have been done and the boat is quicker up wind, but no-one decided to jump and make a hull with just daggers. William Sunnocks has a set of inserts to make a standard T box take daggers !

Fully agree with Rolf.

But, in addition I would add that as a design, RM-D managed to come up with a boat that, right from its earliest days, was fast, sweet to sail and beautifully balanced. This allowed some fairly radical sailing techniques and/or rig adjustments that you possibly couldn't have got away with on another boat.

I agree

I would like to stress:

The crews have excellent sailing technique. All thos little things make a big difference For example watch how they trap going to weather, it's textbook.

The current Tornado's, Marstroms, are strong. You can push them hard without worrying about breaking anything. It makes a difference in the way you sail.

Yep ,agree with Rolf also and as others noted particularly the calibur of sailors on them .

Place these teams on any type of cat --{like f-18hts for example} --in any event --{little AM Cup } in Italy --and they sail them faster than ever previously recorded at higher speeds around the course.

The only negative aspect I,ve heard about the T from T sailing teams is the tendancy of the narrow knife like bows to dive into waves when overpowered with the added spin .

This makes perfect sence as the original design intended a main and small jib only , and the class wished to maintain the original tolerances for hull design ,which was often in wood or stressed skin plywood method of construction in previous decades.

I would like to see more innovation in rigs -sail plans -etc in the 20 ft size range ,--The Marstom 20 seems a beautiful functional lightweight design as well .

Real innovation will best develop if there are more open racing type events and classes available for the innovators ,-the speed sailing trials are always fasinating for example .

In the 20 ft range there are numerous cat design choises now .The new H-20 is supposed to debue soon ,-the Ventilo 20 designs seem excellent -the Marstom of course -and several others seem comperable to the T or potentially faster with the same calibur sailing teams on them .

CDR

New H-20? what is this?

My opinon is that Tornados can sometimes be faster than other 20' cats because of weight and width. Tornados are lighter than many other 20 footers and also wider than many.

GARY

Hey Jake

hope I,m not continueing rumor of a mythical new H-20 version Fox -
A lightweight larger beam version may be exactly the modification the base design needs .
it was on this thread --you noted people are only guessing --rightly so -http://www.catsailor.com/forums/showthreaded.php?Cat=&Board=Test&Number=50431&page=2&view=collapsed&sb=5&o=&fpart=1

Well it would have to come from EU. It's my undestanding any Hobie Cat produced in the US has to have a comptip. Can you imagine a carbon mast with a plastic comptip... makes my head hurt just thinking about it. (joke)

Now if Hobie makes a carbon rocket oh say made in China, and delivers the boat all up for 19K... All other 20 footers are toast! If it's to be yet another 30k dollar multihull, I just don't see much demand, especially when the M20 and Eagle have been available for a couple of years now.

Dave

Hi Dave

Didn,t realize the Marston or Eagle were 30 k --whew !

Wow -I,m gettin old ,-I remember{way back} buying my first then brand new state of the art H-18 for about 25 hundred --

The comp tip is a disaster ,-{another old sailing recollection} --they need one of these little faces with a long grey beard on it --After racing a Hobie 21 with 33 ft mast with comptip we were packing up ,---about half way down in lowering the mast the base slipped out and one of the crew tryed catching it ,--it was so heavy it broke his wrist ..--

Rather than China building it maybe just one of the smaller excellent build shops here ,---or perhaps some brilliant chemical engineer can develop C F or similar lightweight method of const. material that does not conduct electricity for H-US . Or best solution ,-import it just as the Tiger and market the new larger beam lightweight version FOX as a HT Formula 20 Class cat .Believe there is a set of rules outlined that the Morreli -Melvin design Ventilo model fits into among others .
http://www.morrellimelvin.com/page29.html


For 30 k catsailors might just as well go all out ,put a racing group of 3 or 4 togetherb--split costs ,-trade off as navigator helm and spin crew at events ,spend a little more and get the 33 footer . Mike at SAILMAX is attempting to put together several of these for next season .
R-33 sailing video --realtime player --zztop music
www.r33.com/video/R33.mpg

Granted, we don't have much to go on - but my brief impression was that this 'experiemental' fox, whatever the configuration, is not a production model.

Not a fan of it but, plastic comptip. I thought it was epoxy-glass lay up.

It's really all about the beam width. There are other boats with similar hulls, sail area and weight but lacking the T's beam width they are proportionately slower. The P19 is a perfect example. Hurricane 5.9 is another.



True, and this is one area where newer boats like the P19 have improved over the T's original design. Though a tiny bit shorter (P19 is actually 19' 3") the P19's hulls are much 'fatter' forward of the front beam than a T. They exhibit a high resistance to nose diving because of all that extra buoyancy in front where you need it. You have to make some big mistakes to get a P19 to dig in badly. I have sailed along for miles solo reaching with the tip of the lee bow a couple of inches under water without a care(I was too light to keep the boat balanced even hiked out with my toes on the transom). And the P19 is still a 'flat top' hull like the T. The really modern boats have elliptical cross-section hulls like a u-boat, so are happier than a seagull at a landfill sailing with a hull buried.
But without that extra beam width, you just don't have the righting moment to keep the heel angle down to a reasonable amount, especially upwind, like a T can. So you never really get to take advantage of the sail power you have.

Jimbo

Not to get too far off topic but I'm pretty sure it's a fiber (glass) reinforced plastic (not epoxy or a polyester variety).

Hi Grob
a follow -up question along the same lines on catamaran sailors ideal 20 ft cat -it's design and features sailors would like to see -

Improvements from the standard benchmark Tornado design of a 20 ft cat may be a good place to start as the length and beam ratio seem close to ideal at 20 and 10 ft .

Here are mine -

Weight --as light as modern tech allows consistant with strength to race in surf and extreme conditions --
There are no standard stantlings for cat design loads -they vary with each designs various specifications .

Sail Area --the trend towards larger flat top mainsails continues ,-this is good . Some design sails per the rating measurement proceedures which rates this type of high aspect sail configuration faster ,which is correct ,-but it is a shame to add sail area where it is less effective to meet a rating rule .

Suggested a pure rating system for cats that uses only actual L B W SA measurements in a TEXEL type base power formula with a P handicap feature and same SIMILAR NUMBERS in P scale of relative time to distance traveled added to this basic pure design measurement number .--The only thing needed then would be top ranked T sailors of equal ability to spend a week or two switching boat types and racing each type to record comparative times, and we would all have a near perfect rating system .
sorry --off topic -

With the basics of L B W and SA established -that leaves specific features -
SAILS -jib no jib --preference -small self tacking jib
SPIN -higher aspect ratio -set further out on an extended pole -the longer luff dim .and higher angle is more efficient and creates more lift ,--via Aussie 18 type kites
A mid pole snuffer or snail type spin retriever --and would like to see a winch handle type devise used in the spin system to ease ware on hands and increase ease and speed of sets and spin take downs .
An internal type spin halyard system .

Would like a reef system for the mainsail -

Mast -CF LIGHTWEIGHT -in as areodynamic a section as possible --check out the current A Class cats --whew

Hull shape --canted hulls --deeper bow sections --eliptical top decks forward .

CROSSBEAM -radiused -higher off the water -in eliptical shape to avoid wave slap --the H-18 -designed in 77 is a good example -

BOARDS - canted -type --would not mind for and aft boards to help balance the spin --the forward boards angled to assist lift w spin --semi foiler type .

Rudders --larger -possibly a thru hull stern type design to help eliminate the cavitation problem .T foil shapes seem popular but have yet to sail with one .

TRAMP --more open areas for racing in seas --more storage areas and areas thought out for tools flares-extra marine radio -food water etc along with hardware leads and placement options .

Hardware --leads for control lines lead aft to stern trap crew positions -downhaul -rotator -etc
Forward location for spin blocks -center main sheet -
added cleats for temporary holding on spin sheet or others

built in electronic compass location on spin-pole

there are numerous other options -preferences and design aspects catsailors would like ,-sure I,ve not thought of numerous features and ideal options for a twenty footer - --Carl

It's here already. It's called basalt fiber; ~80% of the strength/stiffness of carbon (e-glass has about 50%), electrically and thermally non-conductive and oh yeah, it costs only a little more than e-glass since they mine it rather than synthesize it like carbon fiber.
Right now carbon is still sexy but some day soon some bright new company will figure it out. It's about the performance/cost, bang/buck however you want to slice it! If we go through another carbon fiber "shortage" ($$$) like back in the eighties, it will probably happen sooner rather than later.

Jimbo

It would be interesting to read what John Forbes would have to say. If anyone knows why the old boat is fast, he would be the man.

hello,
you can't really compare the tornado with production 20' boats. the stifness of the tornados these days is the main difference. they used make tornados more flexible in the beggining. $2600 for a brand new boat imported from England. H14 was $1195 by comparison. the stiffness/low weight thing is the main reason tornados cost so much more than say an I20, and the main reason they are faster.
all the other stuff people wrote is true too.
As for carbon, the shortage is already here. Our suppliers told us no new carbon for 3 years. the military gets it all. that basalt fiber should be getting real popular. if anyone has a replenishable source for carbon i'd sure like to find out where it is.

Is the Tornado especially low-weight for a 20 footer? Between 130 to 145kg's platform weight (sans mast/standing rigging) to be class legal. What does e.g. the I-20 weight?

Perhaps I should ask, is plywood really that good as hull materials (the T was designed for tortured ply construction)

My crew tried to puncture my hull with her trapeze hook about 3 weeks ago. Resting on the hook with her 55 kg weight and for good measure she started by slamming into the deck and then compounded by slowly sliding of the hull dragging the hook with her. Result : over about 50 mm the paint has been scrapped of the hull and over about 100 mm you can see/feel a very shallow depression (the track made by the hook). The single layer of class is fine and only the force of the scrapping is revealed by the fact that some fibres are curved in the direction of the hook moving. No loose fibres or other damage, just some small repositioning. Epoxy coating is in tact, timber (4 mm thick in that area) is fully in tact, glass layer (only on the deck between the beams on my boat and a single layer of 150 grams). damaged area and the area around it are completely in tact without any secondairy damage. No delamination (hardly possible on my boat as I hardly have an glass on my hulls), no cracked zones, no buckling, no large dent, no what ever !

Actually the damage is purely cosmetic. A touch of paint will cover the area that was scrapped bare and then only a very small depression (the 100 mm track of about 5 mm wide) will bear witness of what happened. I can live with that.

In my opinion, if this happened to a foam sandwhich hull then I would have had a punctured outer shell and a glass repair job on my hands instead of a small "touching-up" paint job.

I'm now a full believer of marine ply as an excellent catamaran hull building material !

Wouter

Ply is a brilliant material for rigid low-weight construction - especially when combined with epoxy. My '84 trials boat was constructed from 4 and 5mm tortured ply reinforced with epoxy and locally reinforced with woven rovings and epoxy. It was stiff and fast and came in so light that we had to have 'heavy' centreplates made as we had run out of allowable maximum correctors!


The added beauty of a varnished boat is just a bonus

John, those old wooden T's are incredibly beautiful! And I agree with Wouter that wood is still an excellent material. Wood fibers are superior to glass when testing on repeated cyclic load. (The glass doesnt fail, but the matrix often do, I believe).
Wouter, I do think that plywood (if that is what you used) can delaminate..

I am wondering a bit tough, as the T was a plywood design. Are todays composite mass produced boats heavier than a ply design would be? Are they no stiffer than a ply boat (with comparable beams)? Are the glassfibre boats just a economical question?

Yes.


Wouter

I agree with you that a glass fibre foam sandwich hull would have faired much worse. Two anecdotes:

(1) On a light air day in between races I thought it would be really funny to push my crew in the water. As I helped them back out they tried to pull me in and dragged me across the deck. The hook of my harness punctured the glass/foam construction deck of our Tiger - duhh!

(2) A friend of ours tells a great tale about losing his footing on an I-20 and swinging in to the side of the hull such that his harness hook went right through the hull and left him stuck to the side of the boat as it began to heel over. Could have been rather serious! Again, glass/foam construction.

Ply/Epoxy or cedar strip construction rulz for robustness...

Chris.

"My crew tried to puncture my hull with her trapeze hook about 3 weeks ago. Resting on the hook with her 55 kg weight and for good measure she started by slamming into the deck and then compounded by slowly sliding of the hull dragging the hook with her "
Wouter, tell her she wasn`t trying hard enough - you know what my crew did to my hull (4mm ply, no cloth), lost her footing, slammed into the boat and hey looky, 25km from the beach, and a 200mm long tear in the hull. I think what made it puncture was that it was right next to a bulkhead, so the wood could not flex at all and just cracked. I also think she hit the boat side-on, and it was the stainless steel spreader bar, not the hook, that did it.
You`ll need to take your crew out again and practice that move if you want to put a hole in it .
Nicest thing about plywood is the DIY repair option, low tech repair, did it myself and I`m no handyman., and you can hardly see it.
Steve

Back to the question at hand : Why is the Tornado so fast ?
That`s easy - it`s because it`s really just a scaled-up Mosquito !

That is a beautifull T .

Locally here in MI is the Gougeon Brothers West System epoxy ,-there are excellent books and resources available from them as well as expoxy and related filler and boat building products .Wood is a wonderfull renewable engineering -building core material.
http://www.gougeon.com/

Became interested in cat sailing by reading Reg Whites books on the early days of C Class cat racing and what became known as the Little AM CUP ,-their preference was wood const .
wow --just searched a copy of his catamaran racing book for 3.95
http://www.alibris.com/search/searc...mp;qsort=r&cm_re=works*listing*title

Catsailors were building 150 LB A class cats from stressed skin ply and epoxy in the 80s locally and 18 sq meter class cats latter ,--the local builders/ sailors of them after numerous successfull A class designs went to foam and honeycomb core materials only due to the curve limitations 4 MM Marine plywood has ,--that is they wanted hull shapes that had flatter forward hull sections with sharper curves at the waterline than the ply material would allow though the positive aspect of ply was its inherant bending limitation forced a more uniform mathimatical curve as it folded up ,-it is almost impossible to fold up a slow hull shape due to this .

-It would be impossible to build an inter 20 type hull shape from ply for example with its pinched bow sections and very flat harder chined hull shape ,--but the Tornado type hull is ideal with deeper narrower hull and gradual math curves in hull shape .

--The Inter 20 weight is 390 LBs --the Tornado class weight is 376 ,-sounds like yours could have weighed 340 ,-the stressed skin ply version can weight much less or any 20 ft similar hull design can weigh much much less nowdays due to much lighter componants also being available --lighter hardware --sheets lines sail materials mast rigging boats rudder assemblies etc --
believe a 20 w ply const. could weight under 300 all up -possible 250 w spin and all .

Hope that helps inspire some to build .
thanks again for the pic
best regards
Carl Roberts

Carl, and Rolf, thank you for the compliment. (about my old T)

It's so long ago now that I can't remember the exact weights involved, but I think the max correctors figure was something like 5Kg and we needed about 8Kg so because the boats were weighed with all gear on board we had a pair of centreplates specially made with LOADS of reinforcing that came out so heavy that when fitted we were able to put only 4.5Kg of correctors on the main beam

One other thing I would agree with - my boat COULD HAVE BEEN BUILT LIGHTER even back in the early '80's! So with modern techniques, knowledge etc. it should be easily possible to get a 20ft cat under 300lbs if built in ply.

As with everything the trick is to make it hold together

After building and using a wood composite boat, I agree it is superior to glass in many ways. The main advantage of polyester glass over wood, is that it is cheaper. Wood epoxy is a lot more like carbon epoxy than glass polyester.

I pulled a similar trapeze hook stunt a couple of weeks ago. I meant to jump off and miss the boat. Instead the hook caught the deck. Result scrapped paint and no damage to the hull. This was a prepreg carbon Marstrom A.

I suspect, that you could build a monocoque wood/epoxy boat that would match carbon by cold/vacuum molding wood veneer over a plug. By investing in a bag type plug** and using carbon and kevlar reinforcement it could be a case of prepreg carbon trying to match you.



**Bag type plug - 1 version is a silicone rubber bag filled with .5mm steel spheres. The bag is molded to the shape you want and then a vacuum is pulled on the inside of the bag. The bag becomes very rigid. During molding the bags sticks out through what will become the access port. When you are finished, release the vacuum, pour out the spheres, and then pull out the bag leaving only the mystery of "how did they do that".

Well actually the biggest drawback of wood (marine timer) construction is the labour involved in folding up a set of hulls. It also requires a higher skilled workforce. As today labour is a very expensive cost component glass-vinylester wins in the economical sense when trying to make a living off it. Sadly marine ply + epoxy wins in the engineering department. So we are all faced with a choice.

That is unless we can get some cheap skilled labour force in some asian country and have the timber epoxy hulls produced there with a single (light) layer of glass to enhance impact resistance some more. THAT would be the ultimate hull. Thanks to Phills efforts we can make a little bit more complex shapes with folded ply.

Wouter

Hi Wout
Thought it may be helpfull to provide a link to Phil,s excellent boat const. oriented web site
http://www.geocities.com/phillbrander/

different related topic
--good effort on the rating system concepts and proposal,--it seems they all --all types of rating systems and design class rules ,inc Formula Class are all continually works in progress ,--constantly developing and refining over time and changes ,though much the same in intent through yacht racing history .-

Hope boat mfg will eventually get behind a Formula 20 category cat with common accepted basic specifications to go with the F-14 -F-16 F-18 ---f-20? concept in some form , perhaps based on the Tornado specs, which were the original B Class as defined ,-the T developed for selection trials in the B Class as Olympic class catamaran way back .
C

If you wanted to build a T out of wood epoxy, where do you find plans? The official T website shows a deleted link to plans, but no more. Google turned up nada.

Jimbo

I think the real reason a Tornado is SOMETIMES faster than most of the production 20's is the 10 foot beam. You can keep it powered up into a higher wind range than a boat that is only 8'6" wide. I don't know what the Olympic class weight for the T is but I would guess it's under the typical Inter 20 wt. of around 420#.

But, I think if you were to build up a custom I20 with 10' carbon beams, carbon boards and blades, lighten up what ever else you could to get it near the Tornado wt., it would be as fast or faster. The I 20 has very fat forward sections and a tall bow, you can really press it downwind very hard before you stuff it.

Jimbo,

There are Tornado plans at thebeachcats.com site. The text there claims that they are the Houlton building plans, but a few days ago I showed them to a guy that I work with that worked in Houlton's shop in the late 70's-early 80's timeframe and his recollection was that the plans shown were for an older Tornado design that Houlton worked from. Apparently he (Houlton) engineered a trusswork internal structure that was remarkably strong and lightweight to replace the more conventional ply bulkhead/stringer framework. My co-worker remembered lots and lots and lots of little gussets.

I'd love to see those plans. Although, considering the itch I have to build a boat, maybe it's better that I don't.

I was just over at the TornadoCat Yahoo group, and there are some pics of the Gougeon brothers hull structure. No bulkheads. Trusswork with diagonalized longitudinals. Sweet.

The set of plans that I built my T from were purchased direct from ITA. From memory, I believe one set of plans entitles the purchaser to build 5 boats, although royalties need to be paid on each boat built.

Our boat was built in a similar way to the Gougeon boat shown, with lots of thin bracing and trusswork. The plans don't show this but it is relatively easy to work out for yourself (to replace the re-inforcing shown).

Our main problem was getting access to the official IYRU (ISAF) measurement templates so that we could check shapes as we progressed. Fortunately a friend knew someone who had a set that they had made up themselves in ply rather than the aluminium of the official templates and they were good enough!

If I were 30 years younger, I'd do it all again

The plans and building tips on theBeachcats.com was collected and distributed by Jerry Houlton.
I have learnt later that Jerry bought the moulds for the Gougeons Bros. cold moulded T's, and your friend is probably thinking about the building of those.

If one builds a Tornado, they have to pay the ITA a building fee when measureing it. It will not be allowed to race or measured before the building fee is paid. The ITA pays Rodney royalties for every boat measured I believe (at least they did earlier, but I heard something about re-negotiation the deal with him).

The templates can be bought from ISAF, in mylar these days I think? They also supply the original plans, but I think Jerrys notes are superior.

If anybody is interested in building a T in plywood, they should join the T-cat list at Yahoo, as there are several possible modifications to the internal structure shown in Jerrys notes.

John: Was the wooden T on the picture earlier homebuildt? If so, whow!

Rolf, Yes (with the considerable help of a cabinet maker) and Thank You!

Many moons ago I help someone unload a Wooden T at Rutland before a cat open there. The boat was fantastic. The Black 911 Turbo he towed it behind was not too bad either !

And you spent a couple of years refining your design and most importantly - learning how to race it.

With the Tornado, there is a lot of detailed information on tuning the rig and how to set the controls. When you ask a question you are likely to get a very precise answer, like 25 cm inboard from ..... . Also you can buy sails with a tuning matrix that was developed by 3 Olympic Teams training against each other for 6 months. This makes it easy to have a fast boat from the beginning. With a 10 ft wide I20 you are starting from scratch. This is one reason the newer faster designs have a hard time beating the Tornado.

"Our boat was built in a similar way to the Gougeon boat shown, with lots of thin bracing and trusswork. The plans don't show this but it is relatively easy to work out for yourself (to replace the re-inforcing shown). "

John, if you have any photos/ sketches of how the cross-bracing works and what you fix it to on the hull sides I`d be interested in seeing that - The SA Mosquito`s are built a bit heavier than the Auzzie boats because we don`t get the lightest plywood sheets here, have to make do with what gets imported. If we can save a bit of weight on the internals I`d be keen to investigate further.
How much weight do you think that building method saved from the conventional method on the T ?
Most of our internal bulkhead are polystyrene except for the beam bulkheads, bridle bulkhead and daggerboard case stiffener, so not sure if we can save that much weight. Would only be worth building new hulls if I KNEW I could get 4kg per hull lighter. Not likely when they weigh about 21kg each though, although the Auzzies build them to 18kg or thereabouts, so could be possible ?

Steve,

I don't think I ever kept any photos from the build of 'Eric', but if I did, God only knows where they'd be now....

Essentially, where the plans showed bulkheads with lightening holes drilled in them, we built diagonally braced trussed frames. Where the plan showed 6mm, we used 5mm. For 5mm we used 4mm and so on. The re-inforcing under the beam trays was honeycomb paper and epoxy sheet (I've still got some in my garage ) and the longitudinals in the bows were balsa! Basically we tried to think lightness at every opportunity.

The deck beams were all shaved and shaped and were braced to each other before the decks went on. We did away with the gunwhale reinforcing on the tramp area of each hull and instead of aluminium track, we projected the deck out over the edge, re-inforced it from underneath, then drilled it to take the tramp lacing.

The area where we couldn't really save any weight was the centreboard boxes/main bulkhead re-inforcing just by the main beam.

The beam trays were made to an approximate shape for the beams and then finally shaped using microballoons and epoxy painted in and then the beams bolted in place with waxed polythene to protect them.

Once it all came together, even without the rig, if you lifted one bow the other followed after just a cm or so of movement!

Ah, how I miss that boat.....

One other point...the T is a moving target...keeps getting faster as new techniques/technologies are introduced. Not many classes allow this...newer Formula fleets, A cat etc are the few exceptions I can think of.