1999 Designers Report

Designer's report to the 1999 World Council Meeting

The Unfolding Dream

Milestones in Light Sailboat Development - 1950 to 1999

My Starting Point: - Popular1950's dinghy classes such as Heron, Enterprise, Lazy E, Y-16

Principal Developments 1960 to 1975: - Key development programs were carried through by the Northbridge Group, and are reported in my book. Our object was "Most fun and highest performance within the strength of a man and a woman to handle in the water and out". Design criteria were set by the women for whom the class was being created. They did not want trapezes and they did not want complex spinnakers.

Some of our achievements were -

Hull - Structure - Development of foam sandwich hull - lighter weight

Finer entry - Faster through waves

Flat run - Controllable at high speeds

Consistency - Developed until fast in all wind and seastate conditions

Deck - Contoured for egonomics - comfortable to hike.

Foils - New sections - Laminar flow - very low drag

Rig - Flexible mast - Allowed sail shape to be adjusted

Controllability - Easy adjustability of sail shape (but not automatic).

Wingmast - High drive force and speed on reach.

This development thrust lead to the Tasar in 1975. It was 10 to 15 years ahead of its time. It was welcome in Australia. It was readily accepted in UK but unfortunately the key enthusiast (Paul Davies, Managing Director of Performance Sailcraft Europe) was killed. It was deemed to be too far ahead of its time and was not accepted in the conservative USA.

Class strength. The organisational strength of the Tasar class 1975 to 1999 has been due primarily to its regional structure. This ensures that several independent democratically elected regional councils need to exist, and all of them need to cooperate with each other. Organisational costs are trivial. This arrangement seems to require that about the optimum number of interested volunteers has the opportunity to represent and be creative. Their efforts keep the class vital and the general membership interested and aware. Never relinquish the regional class structure.

Principal Developments 1975 to 1999 Rig

Invention of asymmetric Spinnaker - Very high downwind speeds

Invention of single-line hoist and drop system - Simple, fast spin handling

Invention of flexi-tip rig -

More efficient de-powering
More efficient sail outline
Lighter rigs
Lower centre of pressure
Lower sheet loads
Easier rig handling

New rig materials - Lighter topmasts

Invention of automatic rig - Automatic de-powering

Reduction of induced drag - Faster to windward

Hull - Stiffer hull structure - Lighter hulls accept higher rig tensions.

Elimination of drag hump - Hulls which don't baulk at hull speed.

Elimination of bulkheads - Less air drag when apparent wind ahead.

Solid wings - Lower air drag

Fastest wingspan - Varies with expected turns per mile

Unobstructed deck + wings - Admits fast crew movement on skiffs.

New understandings

Sail Carrying Power to Total Weight Ratios for windward planing

Spin to working sail ratios for fastest downwind sailing

Integrated spinnaker system design for control and balance

Human fast-response limits - simple sailing controls avoid crew overload.

Crew age ergonomic limits - unobstructed decks need supple crews

Better industrial design - higher customer value for lower cost.

This is an impressive list of achievements. The evidence that they work is in the much higher performance and the different kind of performance now demonstrated by the 49er and the 29er classes wherever they sail world wide. Other designers may have achieved other advances.

The New Dream. The original object of the Northbridge group, "Most fun and highest performance within the strength of a man and a woman to handle in the water and out", still commands respect. The 1960 design criteria "We do not want complex spinnakers" is no longer valid in 1999. The asymmetric spinnaker with single line control is not complex.

I have been asked by the Tasar owners of my club, as a group, to trial an asymmetric spinnaker on a Tasar. They take the view that to get the information as to how well it can be made to work will be a service to the class, and not a mischief to the class. It is my intention to respond to this request and trial an asymmetric on my boat, and to develop it to the very best that I can do. However, my object goes beyond the Tasar.

It is self-evident that we can now dream of a light, simple body-swung boat for men and women with about the performance of a 29er or better. From my work on the Tasar I expect to learn much about the nature of such a possible new boat.

This will be a machine which will be sailed in a different way. There will be no processions. There will be a focus on "pressure" rather than shifts. I have no doubt that we can do it technically. The interesting question is whether sailors will love it or hate it.

My object in presenting this report is threefold:

1. To apprise the Tasar class of some of the extraordinary advances in sailboat design which have taken place in the years since the Tasar was designed.

2. To advise the class, as a courtesy, that I propose to experiment with an asymmetric on my Tasar.

3. To offer, if the class so wishes, to share what I learn with the class.

Frank Bethwaite