A Treatise On The Principles And Practice Of Dock Engineering

INTERNAL DISPOSITIONS. 25 Liverpool (fig. 5), and the “barb” system at Hamburg (fig. 13). In the majority of instances, however, there is no system at all, the docks being grouped in an irregular and involved manner only explicable on the ground of unforeseen expansion. Internai Dispositions—The internal dispositions of a dock system have already been indicated in the description of the model plan (p. 22), but it will be advisable to enlarge a little further upon them. In large ports it is a commendable (and even a necessary) arrangement to have separate docks for the reception of special classes of merchandise (coal, for instance, and petroleum) which it is not desirable to mix with cargo of a more general character. A very frequent disposition at coating ports is to provide along one or more sides of a dock a series of projecting coal tips, or shoots, served by bnes and sidings. When one side of a dock is sufficient for the purpose, the others may be devoted to miscellaneous cargo, but the dust arising from the shipment of coal renders it advisable to conduct tipping operations as far as possible from any goods likely to be contaminated thereby. At ordinary ports where coal is shipped for fuel mainly, if not altogether, loading can be performed from hulks ranged alongside each vessel, while hej cargo is being dealt with on the quay—a method which saves much time. Petroleum is brought either in barrels or in bulk. For the latter system, which is the most general, tank steamers are essential, the oil being pumped from the steamer direct through mains to storage tanks upon the quay. On account of the extreme danger of fire, petroleum berths must be thoroughly isolated. Grain is discharged either by small portable elevators over a sliip’s side into lighters and barges, or by means of stationary elevators direct into warehouses, which for this purpose are built close to the edge of the quay. Timber used to be conveyed almost exclusively in sailing ships, and the °gs were drawn out through apertures in their bows on to a low quay or into the dock. This method still prevails, but a considerable quantity of imber nowadays, particularly deals, cornes by steamship, and has to be isc arged from the deck or the hold in the ordinary way. On account the gieat amount of quay space monopolised by timber cargoes, it is in many cases found a convenient arrangement to load the timber on to bogies Cl small trucks ashore, or on to large pontoons, afloat, for removal to a storase ground ; or, again, logs and sleepers may be formed into a 8 to be floated into timber ponds. *s one °f the most delicate kinds of merchandise. It is very sus- P le to deterioration and readily acquires a flavour from its environment, ccordingly it should not be discharged in the immediate neighbourhood of u s ances with strong odours, such as fresh fruit. attle necessitate special wharves with isolation zones and lairages. The