The star. (Reynoldsville, Pa.) 1892-1946, 1894-07-25
DOCTORING SHIPS.
PARASITES THAT SEND OCEAN YES
SELLS TO THE HOSPITAL.

NO SURF iTotection TOT iron nuns Aius
Been Found-Tho Old and the New Man
ncrs of Construotlon-Some About
Drydocis and Their Uses.
The sea is a grand and yet treacher.
Gus mother to the thousands Of ships
that sail over its broad expanse, and aft
er buffeting with its storms the ships
must go to their hospital for repairs
This hospital is the drydocll, and the
doctors are the army of careful work
men who look over carefully and repair
every faulty seam or broken rivet.
Salt water is teeming with parasites
Of plant and animal life that cling to
the bottoms of ships, eat slowly yet
surely through wood and iron alike or
rust it away, while they act ms check
on the speed by vastly increasing the
resistance and friction of the water
against the ship. The "gods of the
storms see everywhere" and pick out
each weak seam or faulty rivet and
slowly and surely eat into the vitals of
the ship, so that every few months it
becomes necessary to examine and re-
pair the vessel. To do this she must
come out of the water. The drydock is
just great box of wood, iron and stone,
connecting with the sea by great gate
way. When the ship is ready to enter
the gate is shut and tho water all pump
ed out; then the workmen, with prac-
ticei skill, place the blocks at the bot
tom of the dock for the keel to rest
upon, taking the dimensions from the
plans and drawings of the vessel. These
in place, the dock is flooded again, the
gate opened, and the ship hauled in.
The gate is now closed again, and while
the water is slowly pumped out and the
ship settles down the dockers pull her
this way or that until she rests evenly
on the keel blocks Then shores, or
heavy wooden beams, are braced from
the sides Of the dock to the sides of the
ship, and MS the water is pumped away
the ship stands "high and dry" n ver-
liable "flsh out of water" the bottom,
which was below the water line, cover
ed with seawceds and parasites that
hide the defects they have caused
Then the worllmen scrape and scour
the unwelcome barnacles and grass
away, the seams and rivets are all ex-
amined and repaired, fresh coat of
paint goes on again, and as the dock is
again flooded the ship rises from her
hospital bed, and tho wooden supports
are knocked away until she floats out to
sea again, healthy and strong" to
battle with the wind and sea and tho
enemies of the flag she proudly flies.
When wood was used almost exclu-
sively in building ships, very easy and
convenient means was found to protect
the under water portions of the ship
from the insidious attacks of barnacles
and parasites of plant and animal life.
This was done by covering the whole
bottom of the ship with a plating of
thin copper, for the galvanic action of
the salt water upon the copper was to
convert the ship and sea into vast bat
terry, where the copper became the mega
tive pole and was slowly yet constantly
eaten away, the particles, as they fell,
taking with them the barnacles and sea-
weed as fast as they formed ON the
ship, thus keeping the ships bottom
and sides always clean, SO that the speed
was not cut down by dragging the bar
naoles and yards of seaweed through the
water. Yet even then the copper need
ed repairs; faulty timbers rotted and
crumbled away, SO that every few years
the ship had to go into drydock and be
thoroughly overhauled, each faulty tim
ber replaced and rusty bolt repaired un-
til no loophole was left for the sea to
work upon.
But with the advent of iron in the
building of ships the old means failed,
for where copper was placed over iron
the iron became the negative pole of the
great battery and was eaten away quick
ly, riddling the bottom of the ship with
many leaks. Many devices were tried
the under water portions Of the vessels
were covered with waterproof layer of
wood, which was then coppered as be-
fore, bit wherever there was any me-
tallic connection between the copper
and iron the whole force of the battery
acted there, and holes were eaten In un-
expected and inaccessible places, bring.
ing in an element of uncertainty and
enforcing great care in ''sheathing" the
vessels, as the coating of wood is called,
and the ships still had to go more often
than ever to the drydock.
Then the various methods of painting
the bottoms with protective paints have
been tried and are used in all Of the
cruisers of our navy. The skill Of hun
dreds OF chemists has been exerted to
find a paint that would act as the cop
per does and throw on the barnacles and
seaweed. Great prizes have been offer