KnowledgeForm theory of sailing physics

Lars Bolle

 · 15.03.2009

Knowledge: Form theory of sailing physicsPhoto: YACHT/A. Hoppenhaus
The crab claw sail and how it could be used on a cruising yacht.
Why are modern cruising yachts rigged the way they are? About the difficult search for the perfect rig

The current sailing plans, dominated by slop rigging, are only of limited use for cruising yachts. The major YACHT focus topic deals with the causes of this evolutionary result and shows surprisingly effective alternatives - especially for cruising sailors.

There really is an ideal sail arrangement and shape. But ideal means something different for everyone. One person wants to sail for trophies, the next wants to sail around the world, the third just wants to sail across the Kiel Fjord. Many other factors influence what is considered ideal. The budget, which determines the choice of material for the rig and sails, plays just as much a role as the crew size, which determines the degree of complexity.

The area and the preferred courses are essential. For example, a ketch rig can be ideal for a circumnavigating couple because the sail plan, which is divided into several smaller areas, can be operated with less effort. For the young family, on the other hand, a top rig with a huge genoa can be the perfect solution, because the little ones are more likely to do without a cross anyway and the large headsail pulls the yacht calmly behind it on room-sheet courses even in strong winds, making it less prone to rolling. Such characteristics, on the other hand, will drive the regatta sailor to despair, because for him the race result is decided on the cross, at least on the most frequently practised windward-leeward courses around the marks. He wants to reach the wind with maximum height and be as fast as possible, these characteristics offer him the widest range of tactical options.

And last but not least, contemporary tastes influence the cruising sailor in his choice of rig and the shipyards in the configuration of their range.

It is therefore all the more astonishing that the slup rigging has become so widely accepted. After all, there are alternatives. Studies show that the gaff sail, a supposed wind energy destroyer, can stand up to modern rigs. In addition, the exotic crab claw configuration of Polynesian fishermen is said to be superior to them. Have the rig developers neglected the special needs of the cruising sailor? Answers to this question are now available at the kiosk.

In the focus topic:
Evolution The top and 7/8 rig
Bionics The theory of bird flight
History The strengths of the gaff
Performance The success of the crab claw
Physics The trend towards the "fat head"
Aerodynamics The weaknesses of the ellipse
Development The time of the two-masters

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