Other nations, especially the Norwegians, whose sailors had shown extraordinary courage in maintaining the dangerous North sea trade, had suffered heavy losses, but these losses were quickly made good. The prohibition on shipbuilding for foreigners and on the sale of British ships to foreigners, imposed during the War, and maintained for some time after it, led to a great exten sion of shipbuilding facilities in Scandinavia and elsewhere. The huge "emergency fleet" laid down in the United States during the War came rapidly into service. Japan, whose war losses had been light, had a tonnage, in June 1920, greater by 75% than before the War. By June 1919 the world's losses of tonnage had already been made good; by June 1923 the world's total tonnage, as recorded by Lloyd's Register, was 32% greater than in but the British empire percentage (although all losses had been made good) had declined from 42.8% to 33-8%; the American (including Great Lakes tonnage) had increased from 10.9% to 26.o%.
This huge increase in tonnage was out of all proportion to actual requirements. Indeed, the volume of the world's sea-borne trade, for several years after the War, was greatly reduced as the result of that great upheaval, and the existence of a mass of sur plus tonnage led, after a short post-war boom, to the worst depres sion the shipping industry has ever known. In Jan. 1922 it was estimated that 11,000,000 gross tons of shipping were idle for want of employment, and although the position gradually im proved, as trade recovered, and as it became evident that much of the American tonnage, hastily constructed during the War, could, for all practical purposes, be written off, the supply of carrying-power was still in excess of the normal demand in 1927.
This new revolution in motive power has its dangers for Brit ish shipping, as it diminishes the advantage derived from coal fields within easy reach of the ports, and has combined with other factors to reduce the exports of British coal, to which tramp steamers in the trade of Great Britain look for the bulk of their outwards cargoes. It is not surprising, therefore, that British
owners, while adapting many of their steamers to burn oil under boilers, and placing large orders for motor ships, have taken the lead in research and experiment directed to the discovery of a more economical employment of coal fuel, by the development of a new type of engine or the use of pulverized coal.
As regards the internal organization of the industry, the War accelerated the tendency to amalgamation and combination, especially in the liner trades. In order to maintain their depleted services, many of the big lines absorbed the fleets of other com panies, or purchased tramp steamers, with the result of bringing a still larger proportion of the total tonnage under the ownership or control of a few powerful groups. The tramp trade itself has been heavily hit by the decline in British coal exports and by the slackness of demand due to a surplusage of carrying-power. The line of demarcation between tramp and cargo-liner tonnage is not always clear ; for many tramp owners put their ships "on the berth" for consecutive voyages to a particular port, during the busy season, and many liner companies place some of their vessels on the open freight market, when not required for their regular services. There is no doubt, however, that the lines have gained, and the tramps lost ground since the War; but the necessity for coping with seasonal fluctuations will always provide employment for tramp shipping, and any large increase in the volume of world trade will lead to a revival of demand.