Catamaran

James Wharram writes to us...

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"Dear Editor,
This week the prestigious English Sunday Newspaper, ‘the Observer', had this headline in relation to the upcoming French elections: " If the Left wins in France, a critical battle of ideologies must surely follow."
The French Left (I class myself as Centre/Left/Green) is revolting against the excesses of the world of bankers. This movement is comparable, in present day European politics, with the original French Revolution of 1796, which was against the financial waste and luxury living of the French (and European) aristocracy.
Many modern luxury products are an expression of the Present Day financial waste.
Many of the latest multihull designs pander to this market. They are boats for affluent Urban Man, so he needs to make no adaptations to be on the water. The boats have become holiday villas on the water, great in semi-sheltered waters, less great for more serious sailing. Their cost is now the equivalent of an expensive second home.
This week I received my copy of March Multihulls World, which on page 50 had the headline: ‘Ten innovations which have revolutionised the Multihull', by Emmanuel van Deth. In this article van Deth praises various ‘improvements' made to multihull design, implying they have made modern multihulls better boats than their predecessors.
Several points in van Deth article stress luxury and personal comforts as top achievements in latest multihull developments. Nowhere does he question the consequences of:
1)    how the usage of exotic materials, the addition of many gadgets and high tech hardware has affected the cost of the boats.
2)    how the increased freeboard has affected the windage, how these boats behave in gale conditions as a result.
3)    how the increased hull volume has increased hull drag, to be overcome with larger more expensive rigs (needing more expensive hardware to operate efficiently) and needing larger engines.
As a designer of very different multihulls I should perhaps keep out of this discussion, but the first photograph of the article, captioned ‘The development of the cruising multihull in one picture; between the Pahi with its slim hulls, designed in the 1960s, and the latest Sanya 57, there have been a lot of developments...',  has made it necessary for me to comment.
This caption is totally inaccurate, the Pahi 53 shown here was designed in 2000, not the1960s. This design incorporated our latest ideas of what makes a boat a good ocean sailing craft; slim fast hulls, efficient but simple sailrig design, low windage freeboard and excellent seaworthiness. These were not theoretical concepts, but had been personally thoroughly tested in a round-the-world voyage on our Pahi 63 (1994-98).
The Pahi 53 is not trying to be ‘the luxury villa on the water' pictured on the left of the photo, but is still a successful charter boat, used in the strong winds of the Aegean (see photo).
The rig on this Pahi 53 is the very successful and close winded Wharram Wingsail Rig. This rig was first designed in the early 1980s, has minimum mast turbulence and an adjustable ‘square head', i.e. a short, light gaff.  It was designed as a result of attending a Sail Symposium in 1977 run by Prof. Tony Marchai (author of ‘Aero and Hydro Dynamics of Sail'). The conclusions of this symposium were that if one can reduce mast and rigging turbulence and control twist and camber, one would be approaching the perfect rig. The Wharram Wingsail rig does all three. (see: http://wharram.com/site/node/127 )
This rig was many years in advance of the recent squareheaded multihull rig mentioned by van Deth. It is low tech and hence lower cost, as it does not require complicated/expensive ball roller cars, high tech battens, special sailcloth etc. It has been used successfully on several thousands of Wharram designs in the last 30 years.

Weight:
On page 51 van Deth raises the question of light-weight construction, claiming it was "inconceivable 30 years ago to get a 50ft cruising boat weighing less than 7 tons". Forty years ago I designed and built my 50ft Tehini. This ocean cruising catamaran, built in simple plywood, weighed just 5 tons. The Pahi 53, in the photo, built in ply/epoxy/glass, weighs around 7 tons including all its specialised charter equipment.
My 63ft Pahi, built in 1992 in ply/epoxy/glass and successfully sailed round the world, weighs 8.5 tons and has an ocean sailing weight of 12 tons. All these designs have made long ocean voyages and endured gales without any structural failure.
The need for superlight, high-tech, expensive materials only becomes necessary when one wants a luxury villa on the water, or a super light record breaking racing multihull."
James Wharram

www.wharram.com

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