2010 Crew Weight Reply from Frank B

A reply from Frank Bethwaite to Alistair Murray's letter on the crew weight rule

To        Alistair Murray,

Copy    Chris Parkinson,

WTC Exec Sec Julian Bethwaite

From    Frank Bethwaite.                                       

Re Tasar Weight Rule Dear Alistair,

Thank you for your thoughtful argument in favour of abandoning the weight rule. I agree with you that the present rule is not perfect, and that it can and ought to be replaced with a better rule.

I agree also that an open debate will be helpful.  Please feel free to use these comments as you see fit.    At root, your argument rests on one observation from which you have drawn two conclusions - 1.  You have observed that , other factors being equal, crews of total weight of 136kg (300lbs) to 140kg (309lbs) tend to sail faster than crews of any other weight over the normal range of wind and sea-state conditions encountered in dinghy racing. So you argue that - 2.  If the crew rule were abolished, there would not be any adverse effect on the race performance of any crew, nor on the pleasure that women enjoy from participating in Tasar sailing, racing and social activities. and - 3.  That more women would be prepared to sail because their weight would remain private. I do not agree with you.   I think your observation and conclusions are correct for the two of the four scenarios you have observed, but that you have not had the opportunity to observe the fourth scenario, which is the one which destroyed the harmony within the NS14 class in the years 1970, '71 and '72. Let me explain - In 1969 Mark Bethwaite, my elder son, designed a fine-entry, near triangular hull which he named Medium Dribbly.   When fitted with my recently developed adjustable wingmast rig this became a true "breakthrough" marque with a performance level significantly faster than any previous design.   Mark won the 1969 Australian Championships and Julian and I won the 1970 100-boat NSW championships with a series of firsts (we discarded one second). One consequence of the boat's higher speed was that on broad reaches these new boats, WHEN LIGHTLY CREWED, could plane fast enough to bring the apparent wind forward of the beam and in this way could plane earlier and faster. and also sustain the plane through the lulls.   Because of this capability a big performance difference developed between the generally 300lb man-woman adult crews who had always supported the class, and an influx of new owners who joined the class but chose to sail with adolescents chosen to achieve the 250lb minimum crew weight called for by the class rules, and in this way enjoy the new speed. A surprising observation was that not all of the light crews were able to sail faster. In 1971 the adult women for whom the class had originally been developed began to leave the class in numbers because they were beginning to be deemed "too heavy". We clearly had a major problem.   To find out exactly what it was, I did not enter and sail the 1971 Australian Championships on the Hume Weir at Albury.   Instead I timed every boat around every mark in every race, measured and kept constant track of the wind speed, and analysed these measurements. What we learned from that exercise was that when the wind speed was 7 knots or less  -  i.e. in conditions when nobody planed  -  the first five lightly crewed (250 to 260lbs) boats to finish in each race had sailed their races about one minute faster than the first five heavily crewed (300 to 310lbs) boats.   But when the wind speed exceeded 8 knots, the lightly crewed boats planed sooner and faster and sailed their races on average about 9 minutes faster than the "heavies". * From this 1971 work we learned the performance dimension of the problem. * From my 2000 work with the sailing simulator we later learned the handling dimension of the problem. What we can now see is that we were looking not at two, but at four different scenarios -

1. Heavy crew, and Natural handling technique. At present, these would be 95 to 97% of every fleet.   They set their sails perfectly so achieve target speed for some of the time.   They do not coordinate tiller and sheet.  They use the rudder for everything except immediate balance for which they use body movement.   In gusts they luff.   In stronger gusts, they luff higher.   Because they do not ease their sheets in gusts, they do not increase the drive force to compensate for the greater aerodynamic drag, so the boat slows.   Because they cleat or clutch the sheet or the traveler and hold it immobile they regain target speed only slowly after losing speed in gusts and after any other check in speed. Light crews who sail this way slow more in gusts than heavy crews, which is why you observe, correctly, that slightly heavier crews tend to sail faster.

2.  Heavy crew, and Fast handling technique. At present these would be Rob and Nicole Douglass, Jonathan and Libby McKee, Craig McPhee, Shane Guanaria  -  say the three or four per cent of the fleet who consistently finish with very low scores. They set their sails perfectly, scarcely move their bodies, scarcely move their rudders, control heel and speed with small COORDINATED movements of BOTH SHEET AND TILLER.   Sails are eased slightly in all gusts to increase drive force and so maintain target speed.   Sails are eased whenever they sense that their speed s not up to target speed.   So they consistently sail at or closer to target speed than the Natural sailors who do not coordinate.   This is why they win.

3.  Light crew, and Natural handling technique Handling technique similar to heavy natural.   Competitive up to about 8 knots.   Above that they struggle and fall back because they are so slow in gusts to windward, and so slow to regain target speed after any check in speed.

4.  Light crew, and Fast handling technique.  Forty years ago, in 1971 and '72, these were the crews who consistently finished two legs ahead of the heavies.   To windward they flattened their sails a little more, which reduced aerodynamic drag, and they eased sheets to increase drive force in the gusts and so suffered almost not at all to windward as compared with the heavier crews.   Offwind their more lightly crewed boats developed wings as they planed sooner and faster and so spent more time sailing deeper in the gusts, and also used their greater speed to access more gusts. These are the crews you have never seen because they do not now exist. Their effect on the psychology of the NS14 class was devastating.   At a time when the popular culture was "women don't sail" the class had been created to provide "most fun and highest performance within the strength of a man and a woman". For ten years the men had been providing more fun with progressively higher performance afloat. The women had been providing more fun by providing mature support and companionship both afloat and ashore.

But within a few months they were being told, bluntly "You're too heavy.   If I sail with the kid down the street I have a chance of winning, and I value the chance of winning more highly than I value your companionship" Women started to leave the class in numbers. Faced with this challenge, and supported by the class' elders, I was able to use technical skill to create a new boat even faster than the lightly crewed NS14s, and administrative logic to write the world's first performance equalization rule.   The rule safeguarded the new class from any repeat of the recent devastation.   In this way we created what soon became the Tasar which, forty years on, lives and thrives because it offers a unique blend of outstanding performance and mature companionship. I am proud to have contributed to the outstanding performance.

The mature companionship was restored, and has been secured over time, by the crew rule. I invite you, Alistair, to consider my comments, add them to what you now observe, and to reconsider what you think would happen in the years ahead if the Tasar class were to abolish its crew rule.


Frank Bethwaite Designer