The New York herald. [volume] (New York [N.Y.]) 1840-1920, 1878-01-27

LECTURE TO YACHTSMEN.
A. CARY SMITHS TALK TO THE SAVANNAH

A. CARY SMITHS TALK TO THE SAVANNAH
YACHT CLUB ON NAVAL ARCHITECTURE.
Mr.. A. Cary Smith, at Demonico's last evening, do.
iyered the lecture Of tho winter series his
fellow mombers Of the Scawanhaka Yacht Club on
naval architecture. HIS subject the caculat IONS
that would show tho important elements Of u
yacht or vessel. as 10 ascertain what her
performance would DO by comparison with
other vessels Of similar size and dime siops
Mr.. Smith said that he for throe years of
crew Of the yacht Whitecap and yet he could not
tell why shc stored badly. Alter procuring her
model and making all tho calculations no ascertainsd
that tho centre OF tho lateral resistance OF her hull
some distance forward Of tho centre OF the lateral
resistance OF the yachts board. Nothing could be
done IN tho case but TO put deep skag on
her ait, but this would have the effect of decreasing
her speed. With this Introduction The lecturer pro-
cecded TO show how such errors could be avolucd
lie plans OF vessel ON tho black board and made
very elaborate calculation upon miny points. He
showed the transverse section Oh boat ana calculated
inc area In square iecL Then tho ruo was applied
10 the water line AMI IT'S area was shown IN
the same msnnor he then proceeded to
make calculation for the displacement
OF tho boat showing It's tons and dacnals. Such
measurements as were used akon to the outside
Of the plank il they had been taken 10 the OUTSIDE vi
inc ,noets tue result would DO called tne
the centre OF gravity Of displacement, alter
which he made the calculations OF the centre
O gravity OF the immersed and emerged
wedges at ton degrees inclination, or what the boat
rolls and lakes out at that angle. he said that it
very PLAIN that though the centre OF gravity OF
displacement may be all right when The vessel OH
an even keel yet If tho centre OF gravity moves ait
whom she heels over the vessel must BIO de-
pressed by the head and the centre OF
lateral resistance moves forward; the rudder must
DO moved 10 balanc. this or the vessel comes up
the wind. This explains why some vessels steer SO
hard when heeled 10 largo angle The best steering
vessels are thOsc whose centres oil gravity oil I'M
mersed and emerged wedges come very near together.
The Comet, OF the Now York Yacht Club had these
eghttcntns OF ono loot apart, and though she does
draw much water sue can always be steerod with
The lecturer then made tho calculations Of tho
lateral resistance, and found the OF gravity OF
the board when II is down. ccn,roboard should
always have tho centre OF lateral resistance nearly
line with the hull, or the boat will not turn
one pivot. Experience teaches that II tho
centres OF dispaccment, Immersed anu emerged
wedges and the lateral resistance not very
near each other, dsapporlionment IS sure 10
follow. and though good ooa,s may vary great deal,
they all resemble each other IN these points. A
vessel may nave = high sheer ait and look very
clumsy and, yet, beyonu the disadvantage OF useless
weight, the shape may be all that Is DESIRED. The
Old yacht Vision was case IN point All ner various
cenres wcre IN the right place, but superficial OBJ
server would not have thought so. Yet her per-
tormances show cd that these elements were correct
in every particular.