Interesting essay about the HISTORY OF MULTIHULLS (author: Michael Kingdom-Hocking)

...just like to share two short, interesting essays written by the author Michael Kingdom-Hocking about the HISTORY OF MULTIHULLS

Such historical reviews give me a good feeling about where we are today. It's a more easy understanding about the boat constructions we see nowadays floating around as the modern contructions mostly are a following up (not in the sense of a revolution but as an evolution) on the basis our sailing ancestors created as pioneers.

Sailing Catamarans & Trimarans (part 1 of 2)...

As we saw in Sailing Boats Through the Ages, the big problem with sailing boats is that they operate on the boundary between air and water, using the water to support the weight and the wind (movement of the air relative to the water) to provide the motive power... [ 974 more words. ]



Sailing Catamarans & Trimarans (part 2 of 2)...

The ocean-going catamaran entered the western world in 1936, when Eric de Bisschop built Kaimiloa in Hawaii in Hawaii... [ 768 more words. ]

 

The earliest introduction to catamarans in the West that I know of is Heresshoff's Amarsis

 

Apparently the Ancient Greeks had catamarans, and in 1662 William Petty designed one that was somewhat in the flavour of a ship of the day, but not a mono.

 

Love that footage of Manu Kai! The early CSK boats looked beautiful and seem to have sailed beautifully. I've never been able to find much independent information about their performance against contemporary tris and monos outside the Transpac and Southern California. They really do seem to have gone well, though.

The only CSK cat I know of in Australia or England was Golden Cockerel, which never seemed to really perform to the same level. Was it the conditions, the sailor or the boat?

 

I dont know a lot about Choy, Seaman and Kumalae designs, better known as C/S/K Catamarans.

There is an archive website with the ~150 designs... maybe you get there the infos... http://www.choydesign.com/design/legacy.htm

And there is another thread here in the forum: http://www.boatdesign.net/forums/multihulls/csk-polynesian-concept-catamaran-26908.html

The CSKs seem to be interesting boats in the 60ths.... another historical review about Catamaran and the early days here

46 foot Aikane - Rudy Choy design


The Huka Makani Cat...

 

The thing about the CSK boats is that (as Steve Dashew says) history was written by Rudy Choy, and Rudy simply left out stuff that didn't make CSK boats sound invincible. Trying to find out any objective information about their all-round performance is pretty difficult, although they obviously went well in the downwind Californian races.

 

From Jim Young:
Kenumema
I KNEW BOB HARRIS in the U.S. was early involved in multihull design around the same time as I was, also British dinghy sailor Ken Pearce and Hawaiian Rudy Choy. A decade later in 1970, at a most fortuitous time, we were commissioned to build a large 67 by 27-foot Choy-designed catamaran for a French owner, Jehan Morault of New Caledonia. He had tentatively ordered the boat from New Zealand Yachts just before the company went down, taking me with it, but after I set up again, Morault confirmed he still wanted me to build his cat, which was very flattering because he could have had it built by anyone. Perhaps it was because he knew I already had experience with catamarans.
We built the cat out of sheet kauri plywood, almost flat outside hulls and a half U shape on the inside, asymmetrical hulls in cross section. I learnt a couple of things from that boat: she had two rudders but they were no deeper than the boat, the reason being that when she sat on the ground the rudders were still free to move because there was no weight on them, but when sailing, by the time water passed along the hulls and reached the sterns, an eddy layer had been created over the 60 plus foot length which meant that the rudders had to turn 20 degrees before they began to touch "hard" non-eddied water. On an aircraft that sort of thing would lead to stalling and a crash, rather like the situation in the early days when knowledge of aerodynamics was not great, where the tail-plane would get caught in turbulence set off from the wing, causing the pilot to lose control.
In order to launch her on Takapuna Beach we dug a hole with a bulldozer deep enough for the truck and trailer to drive into, lower the cat hulls to level hard sand, then drive away. Later the sand was bulldozed back, leaving the cat waiting for the tide. A crowd of interested spectators built up to watch, Kenumema finally floated off.. Next day all evidence of her presence was gone. Today had we tried anything like this we probably would have been arrested!
Kenumema was very difficult to steer because she also had the same depth for'ard as aft – and any boat that draws the same amount of water there, always wants to steer by the nose. She kept swinging this way and that so badly that you'd put helm on to bring her back on course, and as soon as she started to turn back, you'd put the helm on the opposite way. There was no way you could keep up and therefore the wake behind you was never straight. For some reason the autopilot could make the boat steer a straight course because it would pick up the slightest movement off course much earlier and correct it before the wandering sequence began. But hand steering a straight course was near impossible.
A condition of the building contract was that the final payment would be made on delivery of the catamaran to New Caledonia. But there was a complication. We had borrowed from the bank to finance the construction with the catamaran itself as security, but once outside New Zealand territorial waters the bank had no legal rights. No-one had thought of this so after weeks delay the bank finally had to let the cat go just to get paid. Meanwhile the hurricane season was upon us.
When we finally got away, the expected downwind slide was not to be. Once we cleared North Cape the wind was strong and dead on the nose and freshening. It was a toss-up whether to tack left or right. For three days we were in storm conditions and even took all sail off for 24 hours at one point. Building the big cat, we had doubled the strength of the forward end of the bridge, but this was clearly not enough. The combination of very narrow fine ends and the weight meant there was enough inertia for the constant pitching to get out of kilter with the waves. The cat began to feel very heavy forward and on investigation we found the forward compartments of the eight foot deep hulls nearly half full of water. In spite of our own initiative in beefing up the forward end of the bridge between the hulls, beyond the structural specifications of the bridge, it had partially stove in, allowing water to flow down into the hulls.
Jim Dickson and I had to get inside the bridge cavity and repair it as best we could in order to stop more water ingress. Once the weather improved and we had pumped out, sailing changed to pleasant conditions under spinnaker and we made landfall at Île des Pins where, after a night at anchor, we sailed through reef-strewn waters to rendezvous with the owners' friends at Île Ouen, just off the South coast. They had come down in numbers in their boats from Nouméa to welcome the new craft.
The island sported a game fishing club with a large clubhouse and restaurant with uniformed waiters. In typical French fashion there was a celebratory meal with champagne. In addition to Jehan, his son Jeanno and his cook, Léopold, there we all were, a bunch of Kiwis: Don Mosely, Colin Pugh, Dicko, along with designer Rudy Choy and me. None of us spoke any French; it was a beautiful calm evening and there was Kenumema riding to her anchor in moonlight. They decided we must all go out and christen the new craft, so we all piled into the big dinghy as the waiters in their uniforms and cummerbunds, trousers rolled up, waded out with more trays of champagne. French panache!

 

Very interesting, thank you.

 

Prout Catamarans Ocean Ranger 45: 1965 £ 28,750

This was the first Prout 45 Ocean ranger built in 1965 she was owned by Dr Pugh who took part in the first ascent of Everest with Hilary. When she was built she was a ground breaking design superbly sea worthy and fast winning races such as the Crystal Trophy in 1968. She was one of the very first large glass fibre catamarans built and laid the foundations for the Prout range of 45 and 50 catamarans which proved so successful over the following 30 years.

http://www.yachtworld.com/core/list...nits=Feet&access=Public&listing_id=77572&url=

 

One thing about the asymmetric hull designs of those early cats,...they really lacked the load carrying displacement that multihulls already suffer from,...and it was more difficult to define the lateral resistance center(s) to balance the sailing rig over.

 

asymmetric hull design of Cats and Tris...

That evokes spontaneously a question into my mind. - I remember Norman Cross Trimarans of the 70th, e.g. the 46 foot Ketch which had astern a very asymmetric shape, see cropped extract from the fully pictures attached.

Norman Cross 46 ft. Ketch...


Norman Cross 50 ft. ....


I think the target of this design was to create on upwind courses "kind of natural weather helm" against leeway and on downwind courses "kind of directional stability", isnt ?

How about such extreme asymmetry of Amas (Trimaran outriggers) as seen with Norman Cross Deisgns ?

 

Hä ?
" Pix misinterpretation" , wa !

Where do you see asymmetric floats ?


pogo