Juniata sentinel and Republican. [volume] (Mifflintown, Juniata County, Pa.) 1873-1955, 1894-11-28
DOCTORING SHIPS.
PARASITES THAT SEND OCEAN YES
SELS TO THE HOSPITAL.


No Sure Protection Tor Iron bulls Has
Been Found-yi.e Old and the New Man
rers Of Construction-Somethi About
Drydocks end Their Uses.
The seq is q grand and yet treacher-
Gus mother to the thousands Of ships
that sail over its broad expanse, and aft
er buffeting with its storms tho ships
must go to their hospital for repairs.
This hospital is the drydoclz, and the
doctors arc the army of careful work
men who look over carefully and repair
every faulty scam or broken rivet.
Salt water is teeming with parasites
of plant and animal life that cling to
the bottoms of ships, cat slowly yet
surely through wood and iron alike or
rust it away, while they act as O 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 cat 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 the water all pump
ed out; then the workmen, with prac-
ticed 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 pCll her
this way or that until she rests evenly
on the keel blocks Then shores, or
heavy wooden beams, are brcced frcIn
siiIe sides of the dock to the sides of tine
ship, and as the water is pumped away
the ship stands ''hiSh and dry" vor-
liable fish ont of water,'' the bottom,
which was below the water line, cover
ed with seaweeds and parasites that
hide the defects they have caused.
Then the workmen scrape and scoar
the unwelCoino burnaclcs and grass
away, the seams and riyets are all eX-
amined and repaired, fresh coat Of
paint goes on again, and rs the dock is
again flooded the ship rises from her
hospital bed, and the wooden supports
are knocked away until she floats out to
sea again, healthy and strong,'' TO
bat with the wind and sea and the
enemies of the flag she proudly flies.
When wood was used almost exciu-
siveiy in building ships, a very easy and
convenient means vas found to protect
the under water POI lions Of the ship
from the insidious attacks Of barnacles
and parasites of plant and animal life
This was done by covering TIE whole
bottom of the ship with 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
tery, wherc the copper became tho mega
tive pole and was slowly yet constantly
eaten away, the particles, as they fell,
taking with them the barnaclcS 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 draggins the bar /
naclcs and yards of seaweed through tie !
water. Yet even then the copper need /,
ed repairs; faulty timbors rottcd and /!
crUmblca away, 50 that every few years I
the ship had TO go into drydock and be ,
thoroughly Overhauled, each faulty tim :
Der roylaced ard rusty bolt repaired un-
til 20 lcophole was LETT for the sea to .
woTk 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 a waterproof layer of |
wood, which was then coppcred as be-
fore, but wherever there was any me-
tailic 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 ''shcathing" 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 I
the bottoms with protective paints have
been tried 2nd are used i'll all of the /
cruisers of our navy. The skill of hun
dreds of chemists has been exerted to
find paint that would act as the cop
per does and throw OF the barnaclcs and
seaweed. Great prizes have been offer
ed, and fortune awaits the successful
discovercr Ct such 4 coating for ships,
yet so far nc-,c hes been discovered that
acts completely, AID the iron and steel
ships which start from port with fresh
ly painted sitlos .2d bottoms return il a
few months coated with barnacles and
sea weed, wi.icil, as il trails in the wa
ter, very MAI aterialiy cuts down the speed
and power of the ship. Then she must
be pat IN tho t',y dock and scrubbed and
and rcpaiuted. Still wOrsc than
the barnaclcs and the aeawecd is the
water itself VIXEN it finds -. entrance,
BE- it ever SO snail, through tho paint
to the steel below. Slowly bat surely
it rusts ont 4 littIo pit, which extends
sometimes almost through the plate be-
fore the paint sc-!c drops OF s,:.l dis
closes the defect, which c-a O.. II t.i.n
only be seen by putting { :.,-i9 !. tlry
dock and cz:uui-irg : ;----'a fcot
of her bottc,n pla::-..
This all Shows To- ;;..2s--.r..,.-,- Is Is fcr
the ships to 20 to their Hospital" ard
how careful her 'doctU-5'' ai-Cul5 b.,
for millions OF dollars worth of property
and millions of priceless lives ere car
ried every ycar On these ''rlczscngers OF
the sea- Tho greatest docks i'll the
world are thoGe of the great shipping