Waterbury evening Democrat., 1894-07-21
DOCTORING SHIPS.
PARASITES THAT SEND OCEAN vES-
 SELS TO THE HOSPITAL.

Been Found-The old and the New Man. |
 ners of onstrustion-somcthing About |
 Drydoci<. ss,d Their Uses.
 The sea is grand and yet n treacher- | ous mothsr to the thousands of ships | that sail over its broad expanse. and aft | CT buffeting with its storms the ships | must go to their hospital for repairs. | This hospital is the drydoclI, and the doctors are the army of careful work | men who look over carefully and repair every faulty seam or broken rivct.
 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 as a check on the speed by vastly increasing the resistance and friction of the water against the ship. The gods of the storms sec 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 a 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 dockCrs pull her this way or that until she rests evenly on the keel blocks. Then shores, or heavy wooden beams, are braccd from the sides of the dock to the sides of the ship, and as the water is pumped away the ship stands high and dry" n yer itablc fish 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 workmcn scrape and SCOUT the unwelcOme barnaclcs and grass away, the seams and rivets are all Cx- 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 the wooden supports are knocked away until she floats out to sea again, "hcalthy and strong" to battle with the wind and sea and the enemies of the flag shc proudly flies.
 When wood was used almost CXclu- sively in building ships, n 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 n plating of thin copper. for the galvanic action of the salt water upon the copper was to convert the ship and sea into vast hat tery, where the copper became the ncga- tive polo 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 tho ship, thus keeping the ships bottom and sides always clean, so that the speed was not cut down by dragging tho bar nacleS and yards of scawccd through tho water. Yet even then the copper nCCd- ed repairs; faulty timbcrs rottCd and crumbled away. so that every few years the ship had tO 20 into drylluck and be thoroughly OvcrhCul,Sl. each faulty tim Der replaced and rusty bolt rcpIircd un- til no loopholc was left for the s,a 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 tho | 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 q waterproof layer of wood, which was then coppcrcd as be- | fore, but wherever there was any me- tallic connection between tho copper and iron the wholo force of the battery acted there. and holes were eaten fin un- expected and iuacCcSsiblc places. bring ing in an element of uncertainty and enforcing great care in ''shcathing' the vessels, as tho coating of wood iS called, and the ships still had to go more often than ever to the dryduCk
 Then the various methods of painting the bottoms with protective paints have been tried and arc used in all of the cruisers of our navy. The skill of hun dreds of chemists has been cxcrtcd to find q paint tl.at would act aS tho cop per does and throw off the barnacleS and | etiNtfHu tHTtit lTlEtS nave th'tn CutT- ed, and fortune awaits the successful discovcrer of such a coating for ships, yet so far none has been discovered that acts completely. and the iron and steel ships which start from port with fresh
 ly painted sides and bottoms return in q few months coated with barnaclcs and sea weed, which, as it trails in the wa.
 ter, very materially cuts down the speed
 and power of the ship. Then she must
 be put ill the dry Jock and scrubbed and
 scrapcd and rcpaiLtod. Still worse than
 the barnaclCs and tho sCaweCd Is the
 water itself when it finds an entrance,
 be it ever so small, through the paint to the steel below. Slowly but surely
 it rusts out n little pit, which extend:
 sometimes almost through the plate be fore the paint scale drops off and dis
 closes the defect, which can even theI
 only be seen by putting the ship ill dry
 dock and examining every square foo
 of her bottom plating.
 This all shows how necessary it is fol , the ships to go to their hospital" anf !, how careful her doctors should be
 for millions of dollars worth of propcrt, and millions of priceless lives are car
 ried every year on these messengers O
 the sea" The greatest docks in tn
 world are those of the great shipping !, port of Liverpool. Washington Star. U
 I Will Take a Vote Monday.
 . LONDON, July 2l.-It has been arrange
 that n division on tho cvictcd tenants bll n will be taken on Monday next in tn :, house of commons
 @ Drowned While Baihing.
 IS AsBCRY PARK, N. J., July 21.-Henr