Macca the parallels between you and Frank Lord over on SA is just so similar. At least he has now done the honourable thing and left the foiling topics alone to be discussed rationally.

Macca:
But how do you explain the design of BMWOs Dogzilla?
According to the designers they decided that a bendier platform is faster in certain conditions.
Alinghi was extremely stiff even up to a point where it was causing damage.

Read again, it is about stiffer is not automatically faster.
By what physics a beach cat should be faster, if it has stiffer beams?

And by the way, did you know that Gougeon 60ft Proa Slingshot weighted 1800lbs, build in wood 1977 or 1978. Compare this with a 40ft Marstrom x40.
For smaller boats wood is an excellent material, and if used correctly can be lighter than CFRP in some areas.

Cheers,

Klaus

Stiffer:- maintaining rig tension....

how did the slingshot go upwind? in waves?

Ever picked up a boom from an X40? its not so heavy for the amount of load on it..

Doug Lord was banned by SA. Nothing honourable about that. And things were certainly not rational when it came to his topics. When he tells the Moth world champ he doesn't know what he is saying, certain amount of delusion.

And stiff is good.

One the things Sailcraft of Canada did starting around late 70's was adding more bulkheads which increased sales by the way. One of many that made a huge difference was the one about 20 inches in front of the main beam. SoC had taken measurements and found the cantilever load at this location distorted the hull section. My T without the bulkhead toed in 2 inches, my friends with the bulkhead toed in 3/8" with the mainsheet full on. The beams were the same. Less toe in is faster.

Haven't we reached the point with Macca that often the threads aren't rational any longer to the common sailor but rational to Macca, one of the party has to be "delusional", in your words not mine. From experiance of some fifty odd years of life I can only say that very often world champions make poor communicators and have a poor understanding of the needs of those much further down the chain ( those who actually buy all the goodies and thingies which keep the world champion as world champion ), in Bora's case he has been very good at promoting and helping those involved in foiling.

On the subject of stiffness, yes any rig tension is good and maintaining that tension is a good thing. But to do that will have far reaching consequences, at some point we will have to admit that further " stiffness and that is such a terrible decription of what we are talking about ) will have no further gain or limited gains without harming the structure overall.

When designing the boat I built I always envisaged a central beam taking all the rig loads including the forestay and an x beam ( plus single tube rear beam taking the side loadings, the AC then started to use a Y beam with additional wires as support. My reasoning was that for the extra 4-5 kilos of central beam the reduced loadings on the hulls and beams would easily be compensated. There were other advantages taken from windsurfing of allowing the mast base to slide forward (and sideways to reduce righting moment ) on the upwind legs. Time limits and cost dictated that this was just an idea but perhaps this year I might have a go.

Wood can be just as good as carbon if it is built correctly. It will never be as stiff and light as a composite carbon / glass structure in my opinion but I have seen many a discussion on this on the internet with arguments for and against such that if you take all things into account such as cost and availability, in small boat building it is a very good material to use, take the many Blade projects within the F16's as an example.

Firstly there is no such thing as over stiffness in a catamaran platform. Any one that sails hobie 16s at the top level will tell you that. The h16 platform is bendy no matter what you do to it but it has been proven to death that a stiff 16 is a fast one. Don't bother rocking up to an Australian h16 nats if your boat is not glued together and your tramp is not as tight as you can pull it. You'll be lacking boatspeed if you do. Basic lessons about catamaran sailing need to be learned by a fair few of you guys.

Secondly comparing macca to Drug Lord is just stupid. Unlike druggie Macca can walk the talk. What druggie and Macca share is that they are both characters. Every sport needs characters or it would quickley get boring. I put forward the opinion that anyone who doesn't think very carefully about bagging out macca is being Irrational.

Got any proof of your claims that are not anecdotal? Would be very interesting but I dont think you got them.
Nice of you to say that multiple olmpians and world champions of multihull sailing need to be get some basic catamaran sailing lessons. Perhaps you better pull your head out of your butt and realise that you dont know it all?


Characters have redeeming character traits. All I see in macca pacca is a FIGJAM offering nothing but abuse and bad PR while indirectly pushing the AHPC product.

Yep, there is no proof that a stiff (glued & super tight tramp) H16 is faster than a soft one.... so why do people bother? I think NASA should do a study on the subject.

I'm not aware of any multiple Olympians or world champions in multihulls that would say that a stiff boat is not faster than a soft one. Got any proof otherwise? The only World champ I know from the H16 said that you should always have a fresh boat for a nationals (ie, dont take a 2 year old boat to a nationals because its not as quick as a new one..) Maybe they get too stiff over that time and hence slower???

As for me offering abuse, I think you will find that I am staying relatively calm in a face of outright abuse from people such as yourself resorting to name calling and labeling.

First of all, are we taking advice on boat design from Hobie 16 Single Manufactorer One-Design sailors ?

Many designers still scratch their heads over the "unique" design choices made with that boat.

Other then that your example only explains that a badly designed platform with unbelievable amounts of flexibility is not what we are looking for. Not that "overstiffness" is impossible.

In fact ORMA tri designers and those of larger offshore multihulls tend to disagree with you and your H16 sailors. Now, please don't make the error of putting up the strawman argument that these designers are saying to lots of flexing is good, they don't. They are mere saying that overdoing it on the other side of the spectrum is not desireable either. As so many times in life the optimal point is somewhere in the middle of both extremes.

Other then that your argument resembles the situation where a man who is exhausted from thirst is best helped by thowing him into a large lake. I dare wager he will die either way. If one thing is "not good" then chance are that 100% of the opposite is not good either.

Wouter

Are you really claiming credit for admireable personality traits after having been the main abuser yourself for years ?

Man, your FIGJAM complex really doesn't know any bounds does it ?

Truly unbelievable !

Wouter

"Perhaps you better pull your head out of your butt and realise that you dont know it all?"

Might be time to take some of your own advise buddy.

Wouter. When i sold my H16 it had significantly less flex than the "minimum wieght" F16s ive checked out.

I can quantitatively prove this but that would get me in trouble.

Tris don't need to be stiff to maintain rig tension or to keep their bows facing the right way.

I stumbled on this thread and initially thought it was just a p**s taking exercise. After reading it carefully and a few other threads on this part of the forum it seems there are some people who actually believe there are no speed advantages for stiffer OTB cat platforms.
Those with short attention spans please continue Twittering - for the rest grab a cuppa and I'll offer my views.
I come from a background of thirty years sailing OTB cats at regional, national and world level. I've built and refurbished both timber and foam sandwich boats.
I note the undercurrent of personalities here and provide the disclaimer that I don't know Macca but have sailed against his Super Taipan with Griffo as skipper.
I'll ignore the red herrings in comparisons with gliders and bicycles. The references to mast stiffness are also irrelevant as masts should be matched in bend characteristics, to sail shape, boat type, sailcloth, crew weight, usual sea conditions etc. That is where the beauty of carbon masts comes in. They can be laminated to suit the exact needs.
Platform stiffness though I believe has a significant impact on boatspeed, particularly on acceleration and through choppy water. Going back to basics, the platform is the structure which transmits the power of the rig to the lateral resistance provided by the hull and the foils in the water. Any bending or twisting in the platform absorbs energy which would have been applied to forward motion by a stiffer platform. The class I know best is A Class cats where stiff platforms are the holy grail. The sloppier platforms simply don't cut it - the stiffer platform just inches forward in each gust as the acceleration is more efficiently applied.The timber boats we built in the eighties just could not be built as stiff as foam boats and the last timber A to win a worlds was Billy Anderson in 1980. I agree that stiffening one area sometimes leads to showing up a weakness somewhere else. Simple - beef up the weak area - thats development.
As far as Tornados are concerned, if a cedar T is so stiff where are they over the last twenty years in the Olympics and Worlds. Haven't seen them winning there.
I agree with Aido about H16's. In the eighties the Metcalfe boys pretty much dominated World titles in 14's, 16's and 18's. They had a standard procedure with the supplied boats. It revolved around making the boats as stiff as possible in the short time available. Even to this day the local and very experienced Hobie dealer sets each new 16 up to improve stiffness over the standard factory delivery.
The recent AC saw Alinghi use significant structural bracing to get platform stiffness. Oracle mainly kept it's centre hull as it gradually morphed in to a cat so that it was stiff enough to limit forestay sag
It is true that building stiffer platforms has diminishing returns. However in a restircted development class you would expect people to keep trying for that extra bit. That's the beauty of formula development. Look at the F18's. Would you rather sail the latest C2, Infusion or Wildcat as opposed to the first Tiger with pinhead sail and fat boards and not so stiff platform.
Now, cuppa finished and off to the shed to do the winter maintenance on a bloody timber boat.

Cheers

There are so many arguments against the platform being overstiff outside of sailing, for instance why do rally cars have suspension, mtb bikes, its all about using the power from the rig, engine, human wisely and efficiently. Having an over stiff platform will simply transmit that efficient power into unefficient areas.

I do suspect however that the platforms of the past have been so poor in terms of stiffness that we are now playing catchup and learning that stiff platforms are good. Where do we go then, in design terms it would have to be the end of the two beam setup as just in engineering terms they will never be able to cope with the torsional loadings without being over engineered.

Agree we need to be more innovative in improving platform stiffness. I have two OTB cats designed in the 60's which have three beams which helps bow stiffness and forestay stability. Also larger cats often have three beams. The Alinghi approach with diagonal strengthening is interesting. We've been gluing beams in A's since the eighties and some recent designs have beams integrated with hulls. There must be plenty of ways yet to be implemented for extra stiffness. I tend to disagree that you can overdo it, cost and weight notwithstanding.

Cheers

Hello pot......

Oh, and well said ACE. I have never met a half decent OTB cat sailor that does not think stiffer is better. But let them believe what they want to.

That's a bit harsh Wouter. Some very good sailors have campaigned H16's over the years. They weren't reponsible for the design - the example was about how people with relevant skills were able to improve the performace of an OTB cat by stiffening the platform. I believe the "better" designs still have some improvement in them. There is still twist in the platform of the best A's on the bearaways going wild and I'm sure the kite boats get twist when bearing away wth a gust downwind. It would be good to utilise that lost energy. What is overstiffness and how do you measure it? I would think everyone would want to transfer the power of their rig to the water with no loss - we aren't there yet.

SOME stiffness is good. The stiffness of a component or complete platform is just like every other feature in a boat’s design; it is compromise for one feature over another. To universally apply “stiffness” as something that is better no matter what is a false premise, same as saying more hull volume, or weight or anything other item is universally better in all conditions.

A telephone pole stiff mast has a very limited useful wind range. Composites under load will flex some and if they do not then there are stress concentrations that will fail in time, unless the structure is just totally overbuilt for its conditions (read weight). There are a lot of water forces acting on a boat and not very many of them are in a useful direction to help our sailing. With a very stiff platform these are transferred to the rig. “Shaking” the rig disrupts the wind flow, which is bad for your performance. So now we dampen the rig or sail or something else to make up for the added “negative” forces imparted with a super stiff platform.

Do not get me wrong, I will sail on a stiffer boat given a chance, but it is not a universal constant that makes everything better.