The National tribune., 1908-01-09
SHIP MODELS.

Mathematicians proudly claim that
every action and the resultant of all
forces can be accurately calculated by
means of their splendid science, put
there is nothing that throws them INTO
confusion like the simple problem OIL
the form of a ships hull. 1t would seem
that, to men who can calculate the
course of comets and the movements OF
the stars, such a thing as modelling
ships hull for the swiftest passage thru
water would be as simple as a, %, C. IL
is not There is the widest diversity Oh
opinion among them, as shown by the
years of struggle between the caicu-
lators of the highest skill in providing
q model to contest for the American
Cup. 1t will be remembered that the
contest between the American and BTU
ish designers of swift yachts was dlf-
ference of view as to the spoon shape
and cutter shape" The BRITISH de-
signers built cutters with sharp pows
and long, slender lines, which sat deeply
in the water The Americans following
the schooner plan, which had peei
found SO serviceable in our waters
claimed that water becomes denser ana
more difficult to forge thru in proportion
to its depth Therefore, broad, shal-
low vessel which sat lightly on top OF
the lighter surface water would make
greater speed than one which had TO
forge its way thru the deeper water. a
number of contests and trials have DEM
onstrated that both were right and both
wrong, and that the swiftest vessel is a
compromise between these two ideas.
Consequently in the later contests LOT
the cup both models have approached
each other.
Not many years ago the chief designer
and craftsman for the Russian navy
put forth the startling proposition that
lust SO much water had to be displaced
in accordance with given weight, and,
therefore, as a circle presented the least
surface in proportion to the weight, a
model nearly circular was likely to give
the best results. Admiral Poppoff car
ried out this idea in the construction OF
a number of circular monitors, and ne
built a superb yacht for the Car on
something of the same lines. HIS sue
cess, while being far from as great as
he had calculated, was still much great
er than his opponents had predicted
The circular form was far from the alb
solute failure that had been predicted,
and marine architects began to again
study the forms of fish life, inclining to
the belief that the shape of the turbot
might after all be the best for ships
lines. Still the builders of the ocean
grayhounds'' clung to the belief that a
swift ship had to be in the shape of a
column; that is, breadth of from one
tenth or one-eleventh the length. Again,
1t was found that the skin friction of
this great length went some way to
counterbalance the advantages gained
by the wedge-shaped bow. The great
Cunard steamers, whose performances
have recently attracted so much atten-
tion-the Lusitania and Mauretania-I
have embodied the latest Ideas in ma
rine architecture, and their beams have
been broadened much more than those
Of the competing fast ships across the
Atlantic. The Lusitania, which has
given the greatest satisfaction, has
beam of S8 feet to length of 790 feet,
and her performances have been SO sat
isfactory that it is likely the next great
ships will have a still wider beam.