Evening star., 1942-08-09
Launching a Battleship

Keith explains Pressure factors will
be altered and it may mean altering the
length or slope of the ways, or changing
the amount Of water ballast computed
for inside the vessel"
Again, the original plans may have
called for installation of machinery
before the vessel is launched. Sud-
denly it's foul1> that the machinery can't
be delivered in time-so the craftsmen
who have figured out the center of
gravity on the first basis, have to chuck
again to figure an entirely new distribu-
ton of the ships weight.
The most common method of launching
ships is stern-f1rst although for some
types of vessels, side launching tech
nique is employed, especially by ship
yards OF the Great Lakes and narrow
rivers.
In the sterr-first method, the vessel
rides backwards down the ways in
structure of steel or timber that is called
a cradle" This extends about 80 per
cent of the length of the craft.
'It's like putting her in box and
letting the box slide" says Keith, but
there's far more to it than that.
Besides supporting the vessel against
tipping, the cradle also includes fore
poppets" and after -poppets," rigid
bodies of timber and steel placed at bow
and stern that hug the hull snugly and
are held in place by straps known in
yard lingo as "bellybands."
The forepoppet is particularly impor-
tant, because one of the biggest problems
the launching planners have to consider
is reinforcement of the bow during the
take-off. When the vessel is released,
the stern enters the water first, and
when it begins to rise, the bow Is still
on the ways, with the result that 20 to
Is per cent of the vessels weight is
transferred to the bow section for a
few tick1ish moments.
When you think in terms of vessels
the size of 35.000-ton battleship, you
can see why the forepoppet must be
tough customer, and also why even
veterans like Keith admit that they
always have launching day filters"
Keith says the ship doesn't rest In its
cradle until short while before launch
ing time Before that, 1t is supported on
the ground by keelblocks, snoring and
"bilge cribs" the latter being "log
cabin arrangement of big 12by12 tim
bers, one of which takes five or six
men to handle"
Beginning soon after dawn on launch
ing day, workmen hustle around the ship
like colony of ants, carefully removing
these supports, stage by stage, until the
great weight is transferred to the cradle.
Its like taking the foundations away
from big building, and letting it down
onto rollers to move it away" says
Keith.
Greasing the Ways.
Greasing is the first operation after
the stationary ways are constructed. The
later-day ship launchers even used soft
soap to lubricate the timbers, but Keith
declares that one of the main advances
in r1odern-day launching has been the
development of petroleum products that
can be used at five degrees below zero,
and at 95 above, as we'll as at ordinary
temperatures"
Ripe bananas also have been used as
lubricants. and Keith grins: why not?
and maybe the peelings could be used
as well!'
You could grease a lot of cars with
the stuff on which a Warship slides into
the future, because Keith says the
launchers use about three pounds Of
lubricant to the ton of shipweight. For
example, the aircraft carrier Lexington,
which was destroyed in the Battle OF
the Coral Sea, required 7e,85o pounds.
The average initial pressure exerted
on the lubricants is about 2 tons q square