Maritime transit of oil products is underdeveloped in Russia , but is now recognized as one of the main development priorities in the field of transportation of petroleum products. Russia is planning to expand the use of Black Sea ports as a base for the transit of oil through the straits. Completion of the BTS has established certain prerequisites for the increase in maritime transit through the Baltic Sea . Terms of maritime transit construction costs are determined by the tanker fleet , and in that area experts say the decline , and the cost of freight vessels , which , on the contrary , in recent years has been increasing steadily . In general, the marine transit - a good possibility of political and economic diversification of oil transportation