Resumen del autor, extraído del trabajo. A combined vessel is a ship which can carry both wet and dry bulk cargoes. About 20 years ago the fleet of combined vessels comprised about 400 units equalling about 45 mill. tons deadweight. However, during the last decade most of the larger oil companies imposed an age limit of maximum 15 years on combined vessels which in effect stopped the contracting of such tonnage and thus the renewal of the fleet. Although the possibility exists to extend beyond the 15 years with upto 5 years more through the classification societies' Conditions Assessment Programme (CAP), the tankers and gas carriers by comparison enjoy a 20 years' age limit plus a CAP of upto 10 years. As a result, the fleet of combined vessels today comprises 150 units only or about 15 mill. tons deadweight. During the last 15 years the Bulk Sea Transportation (wet and dry) has increased by an average of about 60% per ton/mile basis - crude and oil products alone by as much as 90% per ton/mile basis.