Replacement of very large and ultra large crude carriers

The technical and economic conditions of World War II that led to the building of Liberty vessels and compared with those that led to the building of the present very large and ultralarge crude carries (VLCCs and ULCCs) for the purpose of revealing similarities that could indicate when a massive replacement of the existing large tankers is to be expected. The Liberties were replaced within a relatively short time by ships of twice their efficiency and in a situation where transport demand was growing and insurance premiums for old vessels greatly increased. International rules and regulations played on great role. The development of tankers has not produced ships that from an economical point of view are markedly better than previously existing vessels; the demand for tankers has not increased during the last 15 years; the insurance coasts of existing tankers have increased only moderately; and the introduction of new international and national rules for tanker design have made it worthwhile to conserve existing vessels. Although there is a similarity in age distribution between the Liberties and the VLCCs and ULCCs, the situation of the two categories of vessel is otherwise so different that a demand for a VLCC and ULCC replacement of the same magnitude as was experienced for the Liberties cannot be expected.