Rena oil spill: Q&A with a naval architect

Professor Nigel Barltrop, the John Elder Chair of Naval Architecture and Ocean Engineering, Research Director at University of Strathclyde’s Engineering Department comments:

1. How likely is it that the ship will break up? Could Rena ship be salvaged in one piece having sustained that type of damage or has it gone past that stage?

“Maybe if the weather was good it could be repaired in situ but that would seem unlikely.”

2. Essentially – what is happening to the ship? What are the forces at play that would create a crack like that in Rena’s hull? Is it due to the position of the ship on the reef? Would the internal infrastructure of the ship have been seriously weakened by the impact of the sea swells?

“The ship is supported over part of its bottom and the water is not providing the usual support to the bow and stern so the static forces will be tending to bend the ship. In addition the waves will be causing changing forces that will tend to grow cracks.”

3. If the ship breaks up in the continuing bad weather, what is likely to happen to the capped tanks containing the oil within the hull? Would they be likely to stay intact potentially allowing for a recovery of them or the oil to be pumped out?

“This will depend on where the tanks are. A ship could break in two and not leak oil from the fuel tanks.”

4. How do you see this scenario playing out based on past experience? When a ship breaks up what sort of hazards does it create for the marine environment?

“This varies a lot. Apart from oil leaks there is the possibility of chemical contamination from cargo. The containers themselves are a collision hazard, especially to fast craft and smaller vessels.”

5. How does this compare to other examples you are familiar with of ships that have gone aground and started to break up? Are there any lessons we can learn from past experience internationally?

“It is a big job to deal with a grounded container ship. Just removing the containers will take a lot of time.”