The nitrogen cylinders that formed part of the stored energy system on board the Emerald Princess were stowed in a harsh marine environment and had significant external corrosion.
The nitrogen cylinders were inspected annually by the manufacturer’s authorised technician. The most recent inspection was two weeks prior to the accident. On each occasion the cylinders were judged to be in satisfactory working condition.
The circumstances of this accident raise the question of whether the current training requirements for authorised technicians are adequate for a pressure vessel stored in a harsh marine environment.
On 22 November 2018 the Commission recommended that the manufacturer carry out a review of its current training processes and ensure that inspections of stored energy systems are carried out by technicians who are trained and certified to inspect them.