As can be seen from this chart, the world tanker fleet has grown in deadweight tonnage from approximately 17 million tons in 1939 to approximately 31 million tons in 1953, comprising 27 percent of the world total tonnage of all ships of 1,000 gross tons and over.

By January 1, 1953, the long-range rehabilitation program had reached a point where reasonable comparisons could be made between the prewar and the present fleets. As shown on the chart, the world tanker fleet increased in deadweight tonnage by 5.2 million deadweight tons between September 1, 1939, and June 30, 1945. However, this increase was comprised primarily of mass-produced tankers or relatively simple design to meet the exigencies of war. Moreover, the increase of 9 million deadweight tons in the tonnage of the world tanker fleet between June 30, 1945, and January 1, 1953, represents, for the most part, shipyard deliveries of tankers resulting from long-range programs.

This chart also shows that the tanker fleet of the United States, totaling 4.1 million deadweight tons in 1939, was the second largest in the world following the British Empire's fleet of 4.8 million deadweight tons. By 1945, the United States tanker fleet had increased to 12.1 million deadweight tons and comprised 61 percent of the world total. However, between June 30, 1945, and January 1, 1953, the United States tanker fleet was decreased by 4.3 million deadweight tons, due primarily to sales of tankers by the Maritime Administration to foreign citizens for operation under foreign flags, transfers of ships by American citizens to foreign flags, scrapping, and maritime losses.

Referring to the figures for the British Empire, it can be seen that since 1945, due to purchases and new construction, the size of their tanker fleet had increased to the extent that on January 1, 1953, the British Empire tanker tonnage totaled 6.8 million deadweight tons, comprising 21 percent of the world total.

Significant changes in the world tanker fleet have occurred in the last 14 years. Several countries have acquired tankers for the first time (China, Yugoslavia, Poland, Chile, and Ecuador), while several other countries have drawn tankers from other registries to their own because of favorable maritime laws. Landlocked Switzerland and Poland now have 3 and 2 tankers, respectively. Several countries not shown on the chart have tanker fleets but the respective tonnages are too small to be graphically portrayed.

The growth of the tanker fleet of Norway is particularly interesting to note, for the war dealt harshly with the Norwegian fleet as 38 percent of her tanker fleet was lost between 1939, when slightly less than 25 percent of the tanker tonnage of the world was registered under her flag, and 1945. Purchases and new construction have raised the present fleet 1.8 million deadweight tons over the 1939 level.

The tanker fleet of Panama provides the most astonishing development of any tanker fleet in the postwar period. In September 1939, tankers of 734,300 deadweight tons were registered under this flag. On June 30, 1945, this fleet totaled 797,000 deadweight tons, an increase of only 62,700 deadweight tons; however, on January 1, 1953, the tanker fleet of Panama had grown to the fourth largest in the world, totaling 3.1 million deadweight tons. Practically all of the present fleet is known to be controlled by nationals foreign to Panama, 65 percent by American citizens, either directly or through wholly owned or controlled subsidiary companies registered in Panama. Also of interest is the fact that none of these ships were built in Panama, but approximately two-thirds were built in the United States, with purchases and transfers of registry amounting to almost the entire tanker total. Several reasons why Panama has drawn vessels from other registries are: (1) Relative simplicity of Panama's maritime code, (2) leniency with respect to safety requirements, (3) less long-term risk in foreign investments, (4) relatively lower taxes, and (5) generally lower costs of ship operation.

An effect of World War II construction has been to distort the age distribution of the present world fleet. This chart, based on the latest statistical figures, shows the average age of the fleet for the years 1950 and 1952. Apparent in this period of 24 months is the moderate increase of 7 months in the average age of the world tanker fleet and also the substantial increase of 20 months in the age of the United States flag fleet. A slight decrease of 1 month in the age of the British and a sizable decrease of 20 months in the Norwegian flag fleets result from the addition of new construction to their respective fleets. The fleet of Panama, like that of the United States, shows a substantial increase in age of 24 months.

The composition of the foreign postwar tanker fleet by age grouping on January 1,1952, is illustrated on this chart. This fleet totaled 14,240,000 tons, of which 33 percent was of prewar construction, 31 percent war built (16 percent by United States and 15 percent by foreign shipyards), and 36 percent of postwar construction. Projecting all foreign tankers on order or under construction as of January 1,1952, but making no allowance for marine losses, scrapping and replacements, it is found that the tonnage would amount to 21,965,000 tons. Only 21 percent of this tonnage will be prewar construction, while war-built ships will amount to 20 percent, and postwar constructed ships will total 59 percent. Comparing these figures with those given for the United States privately owned fleet on this same chart, it becomes obvious that the specter of block obsolescence once again confronts the American tanker fleet since 83 percent of its vessels are war built, and 12 percent of prewar construction. Only 5 percent of the entire United States tanker fleet is of postwar construction. There is but little improvement in this age distribution even when ships on order or under construction as of January 1, 1952, are included, since 77 percent still consists of war-built ships, 11 percent of prewar built vessels, and the percentage of postwar constructed vessels will have increased to only 12 percent.

On June 30, 1953, the United States had effective control over 632 privately owned tankers of 1,000 gross tons and over. Of this total 456 were under United States registry and 164 registered foreign. In addition to these vessels, the Military Sea Transportation Service operates 69 tankers of various sizes.