What needs to be done about the existing tank ships of up to 5000 tons deadweight

Egorov G. V., General Director of Maritime Engineering Bureau, Doctor of Engineering
Efremov N. A., Senior Deputy to General Director of the Russian River Register, Doctor of Economics

By this time a unique situation has formed in the Russian fleet - most tank ships of up to 5000 t deadweight (the so called "small" tank ships) have double bottom and double sides but do not meet the requirements of Regulation 21 of the International Convention MARPOL 73/78 during shipment of oil and oil products of more than 0.900 t/m3 density.

Soviet engineers have developed the concept of a tank ship of mixed “river-sea” sailing type with “double” haul at the end of the 50-s of the last century. This is why nearly all series
of tank vessels were built with double bottom and double sides.

The international requirements to “double” contour appeared much later. That’s why
the double bottom height in the majority of Russian tank ships is less than the height required according to Regulation 19 of MARPOL 73/78.

This situation is common for the whole world fleet since among 3512 “small” tank ships only 151 (4 %) have a satisfactory double haul according to MARPOL 73/78.

According to Regulation 21 operation of the remaining 3361 ships during shipment
of heavy oil grades, fuel oil and dead oil is permitted only till the anniversary of ship delivery
in 2008.

Such toughening of international requirements is connected with the position
of the European Union formed after breaking of the tank ship “Prestige” on November 19, 2002 as a result of which nearly 200 km of coast of Spanish Galicia and France were polluted
with fuel oil.

Possible options of “long-term” measures:
• writing off of old ships and building of new “marpol” tank ships;
• shipment of only light oil, i.e. cargoes of 0.900 t/m3 density and less;
• rebuilding of tank ships into dry cargo ships;
• installation of the second bottom and second sides without changing
the year of building (rebuilding);
• installation of the second bottom and second sides with changing the year of building (conversion).

Maritime Engineering Bureau has developed a range of possible solutions allowing prolongation of service life of the existing tank ships by 10–15 years and providing the level
of environmental safety established by the international community.

However, in practice it is impossible to perform such works on dozens of tank ships simultaneously. A large number of these ships have a two-shaft propulsion system and twill-hull design. This makes it possible to prove their environmental safety for operation within
the internal ways and sea coastal regions of the Russian Federation regardless of the double bottom height being insufficient according to positions of MARPOL 73/78.

In order to prolong service life of these ships the Russian River Register and Maritime Engineering Bureau have developed a special instrument for evaluating the level
of environmental safety in the form of requirements PPP to the high level of environmental protection of ships – new symbols ECO 1, ECO 2 (analogue of class of Norwegian Veritas CLEAN) and ECO 3 (CLEAN DESIGN).

Assignment of the additional ecological symbol within the class is based
on the requirements of IMO and Maritime Administrations in relation to environmental safety
of ships. Herewith, certain provisions of additional “ecological” requirements of classification societies are stricter than the requirements of the effective international documents.

Additional levels of protection against pollution by ships (ECO 1, ECO 2, ECO 3) suggested by the Russian River Register are those means that are capable of ensuring rational operation of the existing tank ships on the one hand and high standard of environmental safety
of ships of new design on the other hand.

Go to Index of # 3(25) 2008

 

# 3(25), 2008
Shipbuilding