Copyright 2018 - Woods Designs, Foss Quay, Millbrook, Torpoint, Cornwall, PL10 1EN, UK
  • home built Flica 37

  • plywood Romany 34

  • lightweight 14ft Zeta mainhull

  • Strike 15 trimaran at speed

  • 28ft Skoota in British Columbia

  • 10ft 2 sheet ply Duo dinghy

  • 24ft Strider sailing fast

  • 36ft Mirage open deck catamaran

You all know the phrase “it's not rocket science” meaning it's not the ultimate in technology and design. Well I say “rocket science is not rocket science, but yacht design is”

I understand the Russians are still using a 40 year old rocket design. When I visited the Kennedy Space Center I met a retired senior engineer who was in charge of the Saturn 5 rockets. I asked him what changes he'd make if going to the moon today. He said, “only the computer”. The rest was basically just a big fuel tank, while I was surprised at how small and simple the engines were.  The space shuttles first flew over 30 years ago, so were obviously designed much earlier. The supersonic Concorde aircraft was designed in the late 1950's

Now think of the changes made to yachts, and especially to multihulls since 1968

It is easy to design something static, like a bridge or a building. It doesn't have to move, the position of the centre of gravity is irrelevant, furthermore all the loadings are static and easily calculated. So you can put a steeple in a corner of a church and not worry about it falling over.

Once in space a space ship has no loads, no gravity and only one atmosphere between the interior and outer space. Even a stationary houseboat/floathome is harder to design – it has to float level for a start.

Harder still to design are moving things, like a car or plane. They not only have to keep their shape and support a load, just like a static building does, but they also have to move efficiently.

Hardest of all are what I call “interface vehicles”, like boats, that work in two mediums at the same time. Air and water in our case. Planes don't usually fall out of the sky, or break when taxiing on the ground. As they say, "flying is easy, landing is difficult". That is because a plane becomes a interface vehicle just as it touches the ground. Space craft have their problems on re-entry when they reach the interface of the atmosphere.

In many respects a multihull is harder to design and build than a monohull. That is because the Centre of Gravity position cannot be changed by adding or moving the ballast. That's why you should think very carefully before making what appear to be even small changes to the design.