Hi all,

I've been lurking here and in a few other forums for a while, trying to learn what I can about cat sailing. I sailed an 18' cat in the mid-80's, and would love to get back into it sometime.

One thing I'm curious about is the relative physical robustness of various classes. On the US Tornado web site I read the following (http://www.tornado.tc/articles/tstory.htm):

"The natural technological evolution of materials, plus the push for the sailors for stronger boats at the same weights, has allowed the Tornado Class to increase its competitive life dramatically during the past ten years. While it had a reputation as fragile and short-lived back in the 70's, the modern Tornados have racing lives of 7-10 years. Many of the world's Tornado sailors, who actively race in other catamarans, know well that the modern production boats have top-level racing lives of 1-3 years."

However, my impression is that these "modern production boats" have a rather stronger following in the catamaran community than the Tornado. So my question is how true the above statement is. What do people consider the expected lifetime of, say, a Nacra or Hobie to be? And in what ways do these boats degrade over time?

A related question is how does the strength of the lightweight classes like the F18HT and A Class compare with boats like the F18? How are those lower weights achieved? Are the hull materials or construction methods different, or do they sacrifice some robustness for the sake of speed?

Mark.

It all dependents on the guys designing and making the boats.

In the F18 class there are many builders now some 12 of them and some have longer competitive lifes than others. The top F18 design currently have many years of competitive platform life. It is however not as easy as equating top boats to big manufacturers. You find good designs made by small and bigger builders and sometimes a big builder gets it wrong.

I general however I can confirm that quite a few modern boats are not really that much an improvement over earlier versions. It is true about the tornado that they have progressed over time. In other classes you have to look at each individual boat and determine wether it is better build than the boat it is intended to replace. THey are all however faster than their predessors.

Boats degrade over time in stiffness (beam landings), hull flexing and general wear. Although the last is often not of very big importance.

With regard to lightweight boats.

A well designed F18 will have a competitive lifespan of many years. Trully well designed F18's are incredibal stiff and I know of two indepent first hand accounts of two different (small builder) F18's that put the hull impact resistance at very high levels. One was using a screwdriver on a peice of control layup and was despite of outside (gelcoat) damage unable to puncture it. The good designers in the class use the full (overweight) 180 kg;s of the F18 to make the boats as stiff and tough as possible and considering the margin they have they succeed at that.

Lightweight boats like A-cats are designed differently and nowadays are more durable than some 15 years ago. As the A-cats are so very light they are less robust but this doesn't make them "fragile"

The next step up in weight are Formula 16 (Taipan 4.9, Stealth, Javelin 16); they get their strength from a large extend by virtue of smaller dimensions and smaller rigs. They regain their speed by being low drag as well.

Example. Imagine you have two sticks of equal length. one being of a smaller diameter than the other. Clearly the stick with the smaller diameter breaks more easily. Now shorten the stick and try breaking it again. You will find that it becomes harder to break the stick with a smaller diameter when the stick is made increasingly smaller. The diameter and material of the stick didn't change, your strength didn't but the way your strength is translated in internal stresses did. Quite a few of the break principles in cat design are dependent in a kwadratic or even 3rd to 4th order way. Meaning that when an element is reduced in length (leverage) by say a factor of 2 that than the loads required to break that element must be 4 times as large as the same element on a non reduced platform.

The next weight saver in the lightweight boat design is the way some elements are designed. For example the boom with webbing on A-cats and F16's and now too on the Hobie tiger can be much lighter than the older booms that featured a car sliding over a rail. The webbing setup transmits the leech tension directly to the mainsheet instead of passing it on to the boom which in turn passes it onto the mainsheet. This puts the boom under alot less load and allows it to be less bulky.

Than of course their is a huge difference in the weight of boards, rudders and stocks. For example the guy next to my P16 has rudderstocks made out of 0,8 inch square tubes. It is significantly stronger than me P16 castings and weights alot less. Even in the F18 class you have builders making boards at halve the weight as those of other builders. Up till now their doesn't seem to be any difference in strengh. Actually two weeks ago a fleet of 5 F18's (Cirrus F18, Nacra F18 and Tigers) sailed over a submerged jetty at full speed in a race and all broke their daggerboards no exception. However the lightest boards of this little fleet suffered the least damage. It could have been luck but not always are the heaviest or even strongest elements exactly what you want. With boards you may want to have it break of a tip rather than the whole board splitting right open from top to bottom. Some builders make REALLY heavy castings and boards.

The next step up in lightweight are the M20 (115 kg; just remeasure by Texel) and F18HT (130 kg)

These boats don't reduce in size and leverage so these make use of thicker layups (increase in weight) or in case of the M20 of higher quality materials. Both use more carbon in their designs. Apart from that they make use of the same tricks like a webbed boom and sorts.

In the end of the day it all comes down on how well a particular boat has been designed.

I know of lightweight designs that have yet to have a single major failure and other heavier designs that have several major failures already. Yes there is a correlation between overall weight and robustness but it dependent to much on particular design choice to say that lighter boats are always less robust.

To give you a good example

A hobie 16 weights in at 150 kg's but is much more robust than a say a nacra 5.5 of 170 kg's

Wouter

The boat that won the last Hobie 17 North American Championship is 18 years old.

Post deleted by jwrobie

Post deleted by jwrobie

theres a lovely "edit" button right there Jonathan

Maybe I can put the statement on the Tornado website in context.

The Marstrom Tornado is very stiff long lived boat compared to any production boat I have seen. (A best quality wood epoxy boat could be a little better but it will be a lot more expensive.) A life of 7-10 racing seasons is reasonable. The worst case would up and coming Olympic team. A boat would be the race boat for ~3 years, the training boat for ~4 years and then sold to buy the next race boat. These boats will be sailed HARD several times a week. A boat that is sailed less, will last longer. I have a 10 year old boat that, the boat at least, is still competitive in the top ranks. The rules for the Tornado allow just about anything in running rigging and controls so most of the controls that Wouter talked about could be adapted to the Tornado.

The early Tornado's were fragile and short lived. In hard sailing, structural failures were not uncommon. I saw a raced out early wooden boat disintegrate crossing a power boat wake. Marstrom was one of the people who applied aerospace engineering principles to how the boat was built to make it last. His boats are not uniform lay-ups. They are complex inside. They use different types of cloth, core, and structure to put strength where it is needed. Since puncture resistance to a screwdriver is not part of normal racing, the weight is put where it resists sailing loads. In simple terms these have become purpose built race boats. They expect 100% of the boats to be raced hard as compared to 20% of the production boats

Also don't think the comment about production boats was limited to catamarans, in fact it may have been directed toward Olympic boats. The boat that comes to mind first is the Laser. A Laser will last about 1 year as a race boat. It's nice boat but it is just not built to survive continuous racing. A Hobie Wave is a tank in comparison. However, it is cheap and replacement parts are available. Production boats that were originally intended as inexpensive water toys were never designed to handle the loads of day in day out racing.

My experience on production polyester glass catamarans is the life is 2-4 years hard racing 4-6 light racing. After that that the hulls start to flex. I suspect the life limits are caused by quality control. I hear and see delaminating problems caused by bad lay-up. This is unheard of in prepreg construction. Big voids show up quickly, small voids don't show up for years but can drastically reduce the life of a boat. The structural problems I have had with production boats were centered around previously unsuspected voids in the lay-ups. Some boats are built well and last a long time, others - ?

There is a big difference between race boats and volume production boats. Race boats are at best built in the hundreds per year. They can either be built by a small company or as a special line of a big company. They are built to race and practice day in day out at the worst conditions allowed by the race authority. Volume production boats are intended to be cost effective for rental fleets and schools, sailed occasionally by happy couples in nice weather on scenic lakes or bought on impulse at a boat show sailed 3 times and then left in the backyard for 10 years.

Guys, thanks for your responses. Appreciate all the good insights. Allow me probe just a little bit further...

Sounds like a lot of experience and maybe some inside knowledge would be very helpful thing for someone planning to invest in a new boat, in order to know who the quality designers and builders are. What's a novice to do? Is anyone prepared to share opinions about particular manufacturers of production cats? Or are there other ways that the reasonably intelligent buyer can form opinions about these things?

Are hard facts about construction techniques of different builders, or their quality assurance systems generally available (I'm guessing not)? Are there any established industry standards (e.g. ISO) that manufacturers can be measured against?

Thanks in advance,

Mark.

Wouter,
The first fiberglass Tornados, 1960s, in the US weighed 450 to 475 pounds. These boats were soft and rubbery and twisty and oil canned easily and made a 'buboink' sound as they did it and had a short life sailing in the ocean. In the early 1990s Mr. Goran Marstrom redesigned the Tornado from the structural point of view and began producing an excellent boat, far superior to any other Tornado built and at minimum weight, 375 pounds. The reduced weight and improved structural integrety of the Marstrom Tornado has kept the Tornado competitive and has saved the Tornado's bacon as far as the Olympics go. Until a new boat comes along with equal or better "QUALITY" than the Marstrom Tornado, the Marstrom Tornado will stay in the Olympics. Today there is no competition.
Bill

I don't think many serious racers have bought a Hobie 17 since the 80's. Dont get me wrong-it is a great boat-I owned one for a few years and enjoyed it. It's just not the same as saying an 18 year old Tornado won the worlds.

Thanks for the info Bill, like I said it mostly comes down on the designing skills of the designer/builder

Wouter

WHOA WHOA WHOA....easy there trigger! I would venture to say that there are a significant number of serious racers on the Hobie 17 here in the south east. I'm considering a Hobie 17, in addition to my 6.0na, in the near future so I can have a single hander with some serious, and relatively local, competition.

Just wait until Sam reads your post! (you should probably unpack your flame suit now )

I'm not a serious racer I guess

Division 9 which is where Jake and Tad fit into has always had a great class of 17's and the REAL Serious racers actually buy NEW 17s from time to time. It may not be the fastest or techie, but who cares when you can go to almost ANY Div9 regatta and sail against other 17s ALL the time, so the fastest and techie doesn't matter since your one design, except for Tad and his future rocket. Even if he showed up with a non stock configuration the 17 sailors would probably let him in the class anyway, because they don't tend to take themselves that seriously...unless he starts kicking butt which might change things