As has been indicated, in harbor improve ments, one of the chief features is to arrange the docks so that railroad cars may be run alongside the vessels, permitting freight to be quickly transferred. This is best accomplished by the modern form of cranes, and great economies are effected when such apparatus is properly designed. In certain harbors the engineering arrangements are such that vessels may be loaded from two or three tracks simul taneously, and two or three cranes may take cargo from one hatchway without interfering with each other. The very latest and best machinery, however, should be adopted, as great advances have recently been made in this field, and the difference between modern and antiquated equipment will be of appreciable importance in the commerce of the port.
Hamburg — where advantage has been taken of the latest developments in harbor engineer ing — has thus a great advantage over New York, where very few piers are laid with tracks, and where not a single pier is equipped with loading and unloading cranes, and the truck man — in all his glory— charges for small lots as much in many cases as the amount charged for long railroad hauls.
In 1911 Hamburg possessed 130,000 lineal feet of quays for ocean liners, more than 5,000,000 square feet of sheds, and 805 cranes for loading and unloading ocean and direr vessels. The docks of Hamburg vary in length from 2,500 to 3,500 feet in length and traveling cranes are run on both sides of the piers. Some five or six ocean-going steamers can lay alongside each of these docks. The fair way between the docks is some 750 feet in width, so that, between the rows of ships on either side of the docks, a row of ships may be made fast to the mooring post in the middle of the fairway, discharging cargoes into light ers, for which purpose floating cranes are at hand. One of the principal piers has a length of some 5,000 feet, thus showing what modern ternal repairs of ships. These dry-docks are owned by shipbuilding companies, as they must necessanly be associated with such establish ments as can furnish skilled workmen and the requisite materials and machinery for doing the work. The dry-docks or basins are provided with gates for the ingress and egress of vessels, and, after the vessel is lodged within and prop erly supported, all water is drained out, pre senting the entire contour of the ship for in spection and repairs.
There are two types of dry-docks — floating and stationary. The former is made of steel or wood, and is designed to permit of being towed from harbor to harbor. The latter, as a engineering has accomplished in the way of harbor improvements under conditions that at the outset were most unfavorable.
In 1912 the port of Hamburg cleared in imports and exports 25,000,000 tons, valued at over $2,000,000,000. The tonnage was 2,000,000
in excess of 1911. The three ports of London cleared in exports and imports $150,000,000 less than Hamburg. One of the reasons for Ham burg's predominance is that it is a free port, goods being warehoused without customs duties being levied.
Docics.
Prominent harbors are equipped with dry docks or basins for the purpose of making ex rule, is excavated into the shore, after which the floor is laid and the three walls erected of either wood construction or masonry —brick granite or concrete. Heavy masonry walls, however, are the most popular, as they are better adapted for withstanding the inward of the earth filling.
In the following are given data concerning some of America's foremost dry-docks. The most important governmental navy yard is lo cated at Brooklyn, N. Y., where the largest ships can be built and entirely overhauled. Here are four dry-docks: two of wood con struction, measuring 491 and 658.9 feet over all in length, respectively, and two of granite, 302/ feet and 571 feet in length. The yard is well equipped with every class of modern machinery. In addition to this, several important private shipbuilding and repairing companies having stationary and floating docks are located on the littoral of New York city, both on the North and the East rivers.
The governmental navy yard in Massachu setts Bay at Boston has, besides an old granite dry-dock, built in 1827, a modern concrete dock of 750 feet in length with 30 feet of water on the sills. Another system is that of Philadel phia, where there arc several navy shipyards having notable dock facilities. An early con structed dry-dock at the League Island navy yard is 491 feet long and has 25.5 feet of water on the sill. A later dry-dock built of concrete and granite has an overall length of 739.5 feet and 30 feet of water on the sill. The Cramp shipyard, known the world over as the place where the greatest number of United States bat tleships have been built, has some of the most notable dry-docks, both of timber and concrete construction, and is well equipped for the con hydraulic lift with a capacity of 4,750 tons, and a length of 446 feet, with two other large grav ing docks, one 420 feet long, with 28 feet of water on the sill, and the other 700 feet long, with 30 feet of water on the sill. The naval station of California is situated at Mare Island. It possesses two docks, the one being 510.5 feet in length, and the other 739.5 feet. The former is of granite, while the latter is of granite and concrete. Another dry-dock is that of the Puget Sound Naval Station, Port Or chard, Washington. This is a structed dock of 460 feet in length, with 30 feet of water on the sill.