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VOL. 39. CLEVELAND, MARCH 11, 1909. NEW YORK No. 10 Facilities for the care of damaged vessels, which have culminated in dry- docks, developed gradually and in much the same manner as did those for the aid of wounded mankind. Prim- itive man received all the crude treat- ment given him for injuries wherever he happened to be at the time of the accident. When his descendant of to- today suffers dangerous cuts or bruis- es, broken or fractured bones, he is repaired in the surgical ward of a hos- pital. A shipyard may be considered as a vessel's hospital, of which the dry dock is the surgical ward, sought by the ship compelled to leave its na- tive element on account of its hull having sustained injuries similar to those mentioned. In olden times if repairs to the hull were needed and the vessel was in waters affected by the rise and fail of the tide, she was grounded at high tide to be exposed at the ebb, when repairs were commenced and hurried as much as possible before the tide 'again came in. If, however, there was no tidal movement where the ship happened to be, it became necessary to haul her on the beach and careen her in order to get at the injury. Although the largest boats of those days were insignificant in size, con- pared with an ordinary vessel of the Present time, it' was- an. exceedingly hard proceeding to beach them and our forefathers invented an easier plan. This was called heaving down and consisted of attaching ropes to the heads of the masts and to stationary objects on shore or to the deck of an- other vessel and then hauling the boat The Dry Dock. BY: T.-M. BROW WN, to be repaired into an almost horizon- tal position. , Although dry docks had. come into use, such a process was the cause of the famous catastrophe to the Royal George in 1782 whereby 1,000 people were drowned and which was such a national calamity that it was perpet- uated in verse by Cowper, the cele- brated English poet. The Royal George, carrying 100 guns, was the finest and most powerful ves- sel in the English navy and the flag- ship of Rear Admiral Kempenfeldt. She was lying off Spithead at the time of the memorable disaster, awaiting fi- nal orders previous to: sailing for the relief of Gibraltar, then beleaguered by combined French and Spanish fleets, when she sprang a slight leak. Not wishing to lose time by returning to the harbor and the weather being fine, the heaving down prccess was resorted to. Through a miscalculation she was laid over more than was intended and a sudden gale which came up threw her upon her side. As her lower deck ports were open, she immediately filled with water and in three minutes went to the bottom and with her went much of a nation's pride and hopes. Designing tke Gridiron- The next improvement in handling damaged vessels seems to have been the designing of the gridiron. A framework of timber was built at a level sufficient to admit of vessels be- ing floated above it at flood tide and grounded upon it during the ebb and when thus left high and dry every part of the hull was easily reached for inspection and repair, The use of slips or marine railways appears to have been adepted at about the same time as that of gridirons. A slip consists of a carriage or cradle working upon an "inclined railway which extends above high water to a sufficient distance for the class of ves- sels expected to use it and to several feet. below the level of low water. The carriage is let down under the water, the vessel is floated above it and the carriage drawn up until the vessel catches it forward. After the ship is in line with the carriage, a steam winch hauls the carriage with the ship upon it out of the. water. In early days a grab purchase performed the work now done by the winch. As larger. ships came into use, dry docks or graving docks as they are termed in England, ciosely followed and superseded gridirons and slips, the former not being employed in these times at all and slips only in the build- ing and repair of yachts and small vessels. Dry Dock or Graving Dock. A dry dock is an excavation on the shore of a body of water and connec- ting with it at right angles. The sides are constructed of timbers or masonry and formed in steps or altars, so that the shape of the dock is similar to that of the vessels but with space left for workmen and light. The entrance is closed by strong and huge gates opening sideways like a lock or falling upon the bed of the entrance or else a caisson is used. If the dock is situated upon a tidal body of water, the vessel is floated in at high tide and the water is allowed ordinarily to run. out through sluices |