Double hull

The double hull is often presented as a solution to the problem of oil spills. It is certainly an effective solution for minor breaches resulting from collisions or groundings at low speeds. However, it does not protect against collisions at full speed, fire, explosions, breaking during a storm or dislocation on reefs, all of which can generate major oil spills.

Double hull

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Possible structures for a double hull tanker


Furthermore, it makes inspecting vessels more difficult to carry out. It inevitably increases vessels’ prices, tonnage and maintenance costs. The benefit of the double hull is comparable to that of a motorbike helmet: it acts as a useful form of protection, but is not a cure all solution.

The US was the first country to impose requirements making the double hull mandatory for all vessels frequenting its ports. The implementation of this legislation in the US complies with the following timescale:

• 1994 for new vessels
• 2009 for existing vessels with a gross tonnage of more than 5,000 (14,000 m3)
• 2015 for all remaining vessels.

This decision, made under pressure from the media and public opinion as a reaction to the Exxon Valdez incident in Alaska, gave rise to lengthy debates in the maritime community and the International Maritime Organization.

After the Erika disaster in France, Europe wished to move towards a global solution through the International Maritime Organization, involving the phase out of single hull tankers by 2010. Faced with the difficulty of reaching an agreement, the delegations decided to create a more flexible worldwide rule: remaining single hull tankers would be allowed to operate worldwide until 2015, but concerned countries (notably the European countries) could choose to ban these vessels from their ports as of 2010.