Kaplan, Sargent and Goodman 
reporter is here, and they found a school in Devon with 20 boys and 
for the sum of £ 500 they have built a 24-foot sailing hydrofin which 
in my opinion will win the £ 2,000 race next month financed by 
Player's cigarettes (footnote D). Iam sorry if I have been advertis- 
ing and I realize now that I have. Would you please edit my remarks 
before they appear in the Journal. 
DISCUSSION 
Peter T. Fink 
Untverstty of New South Wales 
Australta 
It is, of course, marvellous to have a transfer of an advanced 
control technology concept into this field and obviously a lot of success 
has been achieved. What we are dealing with seems to be a very so- 
phisticated kind of curve fitting and I wonder if Mr Kaplan is aware of 
one thing that was mentioned at the IUTAM meeting on manoeuvrabi- 
lity and control in London in April. After a discussion of a very im- 
pressive Ph.D. thesis from MIT by Lt. Hayes of the United States 
Navy, in which he was adapting similar concepts to the evaluation of 
a vast number of coefficients describing a deep submergence rescue 
vehicle, and I think pretty successfully, the discussion after that by 
Mr Nils Norbin of Sweden revealed something which I found very di- 
sturbing and which I think must have a bearing on this sort of game as 
well. He was discussing the question of what sort of law to fit to a yaw 
rate rudder response curve, say y asa function of x and he took 
first of all the sum of a linear term, with an x modulus x2term. 
Then he did it again taking a linear term with a different coefficient, 
plus an x3 term. He achieved very nice coincidence of the experim- 
ental points with both of these curves, but in one case the linear coef- 
ficient was 50 per cent different from that obtained for the other case} 
So it looks to me as if a very great deal depended on just how you 
chose these powers, and when you get to much more sophisticated 
systems like those Mr Kaplan deals with, it must be much harder to 
D. Iwas wrong but only because the British entrepreneur had to 
make do with existing moulds for the floats. The British climate is 
inimicable to the private entrepreneur. 
1692 
