The sun. [volume] (New York [N.Y.]) 1833-1916, 1914-04-12
CUP DEFENDERS WILL
MEASURE NEAR ALIKE
Differences In General Dimen-
sions VIII Figure Little
in Rating.
NEW RULE GIVES LATITUDE
Present system for Time Al
lowancc Allows for Variety
Of Design.
NEW RULE GIVES LATITUDE

II has been figured by many yachtsmen
that no matter what the differences
IN the general dimensions Of the three cup
defenders now building may be. when they
are measured for rating they will figure
abou, the same The present rule Of
measurement gives a designer lots OF lati-
tude. He can do many things In his de-
sign and each one will figure about the
same and go each OF the three designers
who nave worked out the problems for the
defence OF the Americas cup may have
adopted different method. hut under the
present system for time allowance each
will rate very nearly the same.
The present rule taxes driving power
and such elements that stand for speed
and puts a premium on displacement. II
takes into consideration length. sail area
and displacement. Length Is the distance
from the forward end to the after end of
the notaton plane. commonly called water
line length. In the defenders this is lin
tied to about T5 feet. The challengers
named Is feet as the water line length OF
the Shamrock w, and that length must
not be exceeded. The defending club in
sisted that it was not compelled to limit
the length of the defender. ana while they
may be more than 20 feet on the water
line Il is very doubtful II any one Of the
three yachts will exceed that length.
Length Is multiplied by the square root
OF the sail area and divided by the cube
root of the displacement This displacement
Is figured in cubic feet, and there are IS
cubic feet 10 a ton. This Is the bare rule,
but there are limitations to draught, quar-
ter beam length and other things. and II
those limitations are exceeded the excess
is aided TO the length. Draught is limited
10 10 per cent. of load water line plus
LIS feet Any. excess Is multiplied by
three and addei'to length. SO that should
designer figure that his vessel wants
more beam than Is allowed under the rule
ne will have TO pay dearly FOR that In
crease. For a vessel as feet on the water
line the limit OF draught is 1875 feet. A
all the defenders are fitted with centre
boards the designers have got over the
draught question without taking any
penalty
There Is limitation to the quarter
beam length. This length is measured
on a line parallel to the middle fore and
after vertical plane at n distance from i
equal to one-quarter OF the load water line
beam and one-tenth of this brea 18th above
the water line. II the vessel has a beam
" 20 feet the line will be measured two
feet above the water line and Ave feet
from line drawn from the bow to the
stem through the centre OF the yacht
This quarter beam IL also limited.
To find II the square root of the water
line length Is figured and that square root
deduc'es from 100. The result Is the
percentage that the quarter beam must
bear to the water line length. For the
sake NJ easy figuring take a vessel 60
'eet on the water line. The square root
vi 50 is =, and deducted from 100 is 90.
The quarter beam length Of this vessel ID
limited to 20 per cent o. "a, which Is
1FNs feet The cup defenders will be 10
feet on the water line and the quarter
beam length will bee limited to ss5 feet.
This method OF measurement is made to
prevent designers building vessels OF the
srow type or those having wide low after
ovtrhtngs which enable a yacht to in
crease its sailing length very materially
and carry much more sail than a sanely
designed vessel would. There Is "A penalty
II mis- quarter beam is too long. one
half the excess IL added to the water line
length. l; IL certain that the cup design
trs have accepted a penalty on this meas
urement, because the speed OF the mo1cl
can be much improved by So doing, and
tn cost H. not excessive.
Now having figured all these details
the designer has to determine whether he
can do better With large or small
vessel II the displacement is small then
ne has TO cut down the driving power, the
sails carried. and II 1t is large he can
put on large driving power.
II has been said that the defenders
when measured will all rate about SIS.
and that the allowance between them will
be very small. II Is said that the Nanit!e
WI, spread about 1900 square feet OF
canvas. n hcr general measure 'nents
are normal she viii then dlsplace about
lo' tons 10 make her rating Ss. This In a
og vessel for n feet water line. hut all
reports about the Nanite make her II biz
Nsssel She has about So tons o? lead
"a her keel. and the frames and plating
&c, VIII Increase her displacement 10 lo5
Or i07
IN order to make the figures Of the
rating more easily handled only is pei
cent Of the length multiplied by the square
root of sail area and divided by III,
'uh' root - dlsplrce is taken.
III iur Niultle measures 10 feet and tn,
square root Of sail area is 12l, figuring
Vat her displacement Is l07 tons, hei
rating viii be sS.
Another yacht. perhaps the Defiance
ma nr - feet long, spread 10000 squar,
ftct oi canvas and dlsplace 100 tons, He
A.ng unlcr the rule will be SS,74.
'ifl yacht may measure 10 feet length
. aleai $500 square feet OF canvas anC
9N1a" ~ tons, and her rating will b,
4b,ut IS.