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Doctoring Ships

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The sea is a grand and yct a j ous inother to the thousands of shipg that sail over its broad expause, and '. er buffeting with its storms the ships mnst go to their hospital for repairs. ! This hospital is the drydock, and the doctors are the anny of carefnl workinen who look over carefnl ly and repair i every fanlty seam or broken rivet. Salt water ia teeming wisth parasites of plaut and animal life that cling to the bottoms of ships, eat slowly yet surely tbxongh wood and iron alike or rust it away, while they act as a check on the speed by vastly increasing the resístanos and friction of the water against the ship. The "gods of the storms see every where'' and piek out eaoh weak seam or fanlty rivet and slowly and surely eat into the vitala of the ship, so that every few months it becomes necessary to examine and repair the vessel. To do thia she must come out of the water. The drydock is just a great box of wood, iron and stone, oonnecting with the sea by a great gateway. When the ship is ready to enter, the gate ia shut and the water all pumped out; thea the workmen, with practioed skill, place the blocks at the bottom of the doek for the keel to rest upon, taking the dimensión from the plans and drawings of the vessel. These in place, the doek is flooded again, the gate oponed, and the ship hauled in. The gato is now closed again, and while the water ia slowly pumped out and the ship settlos clown 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 dook to the sides of the ship, and as the water is puinped away the ship stands "high and diy, " a veritable "flsh out of water," the bottom, which was below the water line, covered with seaweeds and parasites that hide the defects they have caused. Then the workmen scrape and scour the uuwelcome barnacles and graas away, the searns and rivets are all examined and repaired, a fresh coat of paint goes on again, and aa the doek is again flooded the ship rises from her hospital bed, and the wooden supports are knocked away until she floats ont to sea again, "healthy and strong, " to battle with the wind and sea and the enemies of the flag she proudly flies. When wood was used almost exclusively ia building ships, a very easy and conveniont means was found to protect the under water portions of the ship frorn 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 Balt water upon the copper was to convert the ship and sea into a vast battery, where the copper became the nogative pole and was slowly yet constantly eaten away, the partióles, as they feil, taking with them the barnacles and seaweed as fast as they formed on the ship, thus keeping the ship's bottom and sides always clean, so that the speed was not cut down by dragging the barnacles and yards of seaweed through the water. Yet even then the copper needed repairs; faulty timbers rotted and crambled away, so that every few years the ship had to go into drydock and be thoroughly overhauled, each fatilty timber replaced and rusty bolt repaired until no loophole was left for the sea to work upon. But with the advenc of ii'on in the j building of ships the oid mea:is failcd, for where copper was placed over iroa the iron becamo the negativo of the great battery and was aten away quickly, 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 coppered as before, but wherever there was any metallic connection between the copper and iron the whole force of the battery acted there, and holes were eaten in unexpected and inaccessible places, bringing in au 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 of ten than ever to the drydock. Then the variousmethijis of paintin the bottoms with protective paints have been tried and are used in all of the cruisers of our navy. The skill of hundreds of chemists has been exerted to flnd a paint that would act as the copper does and throw off the barnacles and seaweed. Great prizes have been offered, and a fortuno awaits the successf ui discoverer of such a coating for ships, yet so far none has been disovered that acts completely, and the iron and steel ships which start from port with freshly painted sides and bottoms return in a few months coated with barnacles and sea weed, which, as it trails in the water, very materially cuts down the speed and power of the ship. Then she must be put in the dry doek and serubbed and scraped and repainted. Still worse than the barnacles and the seaweed is the water itself when it finds an entrance, be it ever so small, through the paint to the steel below. Slowly but snrely it rusts out a little pit, which extends sotuetimes almost through the plate before the paint scale drops off and disoloses the defect, which can even then only be seen by putting the ship in dry doek and examining every square foot of her bottom plating. This all shows how neecssary it is for the ships to go to their "hospital" and how oareful her "doctors" should be, for millions of dollars worth of property and millions of priceless lives are carried every year on these "messengers of the sea." The greatest docka in the world are those of the great shipping Dort of


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