Fairhaven herald. [volume] (Fairhaven, Wash.) 1890-????, 1892-11-15
LAUNCHING A VESSEL
OLD TIME METHODS ARE ADAPTED
TO MODERN CONDITIONS.


Poised ON the Ways.
The launch of a modern vessel does not
differ materially from one of older DAYS
except in detail and enlarged response
bility. 1t is now question of mathemat-
les rather than of personal experience. It
is now matter of applied science and not
one of fortunate guesswork The con
structor in these days does not fix the scale
of the inclined plane down which the YES
sci will glide by his experience in such
matters; does not smear the tallow on the
ways until it seems to be enough; does not
adjust the size Of the ways to suit his
fancy. Vessels that cost from 81 900, 600 to
100000 are too valuable for the running
of large risks, and hence the equation, the
formula, the methods of applied mathe-
matics, have supplanted old time ways Of
trusting to individual judgment and good
luck.
Three things are absolutely necessary in
launching a vessel in tidal waters-the
launch must take place on time, must be
OF moderate speed, and all strainiDg of the
vessel must be avoided. 1t is in this last
particular that the greatest responsibility
rests nowadays. A wooden vessel may be
SNpJcNNcu W Il great SlTdlIl, utF sedulS may
open and, as naval constructor recently
put it, 'she may almost be stood on her
head' and yet escape serious damage in
launching. The seams will close again
and the timbers and planks adjust them
selves. Not so with iron or steel vessels
If the plates are strained, the rivets bent
or broken, the injury is permanent and a
matter of the gravest Importance.
IlugW. L l..
fore the keel is laid. The incline of the
plane has first to be figured out. 1t gen
orally varies from one-half inch to one inch
to the foot. Vessels of large tonnage
have less inclination than smaller ones.
The City OF Paris had only one-half an inch
inclination when she was launched. The
cruiser Columbia, so long known as the
Pirate, and recently launched at Cramps
shipyard in Philadelphia, glided into the
water at an inclination Of thirteen-six-
teenths Of an inch to the foot She went
down the ways like race horse. Mr.. Nixon.
the constructing engineer of the Cramps,
planned TO have her in the water in thirty
seconds after she started. She made il in
twenty-nine. More vessels are launched
at an inclination Of three-quarters of an
inch to the foot, however, than at any other
plane.
The ways, as is generally known, con
sist of two parts, the ways proper and the
cradle. The ways proper are stationary
and firmly fastened 10 the ground. The
cradle rests on top of the ways and up
against the vessel and slides into the water
with the ship Between the ways proper
and the cradle the tallow is smeared. This
is generally spread five-eighths of an inch
thick and must be of the highest grade
That used by the Cramps is made in Phil
adelphia and costs from seven to eight
cents pound. About II 900 pounds was
used in the launching of the Pirate 1t is
heated in big kettles IN the shipyard and
spread on by nand. In the case of the
Pirate the weather was so warm that there
was serious danger that the tallow would
melt and run away. Mr.. Nixon therefore
mixed Is per cent. stearine with it. He
also played a hose on the tallow, and went
SO far as to sit up nights with the mixture
TO watch the effect of the weather on it.
The stearine hardened the tallow and the
launch was successful.
Perhaps the most important element to
be considered in the launch of today is the
buoyancy of the water and its effect on
that part of the vessel which is still on the
stocks after probably one half Of the vessel
is in the water. Recently one of the new
English battleships OF the l4,OOO-ton class
was wrecked at her launch. The buoyancy
OF the water lifted her up at the heels and
threw her immense weight forward on her
shoulders, crushing the frames and the
launching ways, and running the boat.
The modern naval constructor reduces this
question Of buoyancy to matter of mathe-
mates at once. He starts with the ques-
ton OF specific gravity of the vessel. II
there were no water for the ship to slide
into she would continue in the line of the
ways until the center of gravity would get
over the end OF the ways, and then she
would tilt. But the water keeps her from
dropping down and holds the vessel in the
line of the ways. This water is the safety
valve of the launch, but 1t must not be too
safe. While the moment of buoyancy
must always be greater than the moment
Of weight, it must not be so much greater
as to throw terrible pressure on the for
ward end of the vessel and wreck IL.
Having arranged all these things, day
and an hour are set for the launch, the