Advertisement

  1. ITV Report

Safety lessons learned from grounding of Hoegh Osaka

The Marine Accident Investigation Branch (MAIB) has published a report into the investigation of the listing, flooding and grounding of the car and truck carrier Hoegh Osaka on the Bramble Bank in the Solent on 3 January last year.

Accompanying the report, a safety flyer has been produced highlighting key safety lessons arising from the accident which the Chief Inspector of Marine Accidents urges the industry to take forward.

Devastation in the cargo area Credit: MAIB
Chaotic scene on board Credit: MAIB
Vehicles on board were badly damaged Credit: MAIB
The cargo ship had inadequate stability Credit: MAIB

Stability modelling and analysis following the accident show that Hoegh Osaka heeled heavily to starboard while turning as a result of having departed port with inadequate stability. Cargo distribution was such that the upper vehicle decks were full while the lower vehicle decks were lightly loaded. Hoegh Osaka was low on bunker fuel oil, which was stored low down in the ship, and the ship’s overall vertical centre of gravity (VCG) was relatively high. Hoegh Osaka’s inadequate stability had not been identified prior to departure. The figures in the pre-stowage plan were significantly different to the final cargo tally; the estimated weight of many items of cargo was less than their actual weight; and no allowance was made for the VCG of the cargo loaded being above deck level. Finally, it was onboard practice to alter the ballast tank quantity readings on the loading computer so its output would match the observed draught readings. It would have been possible to embark additional ballast prior to departure to reduce the ship’s VCG as necessary, but as the shortcoming in stability had not been identified this was not done.

Safety Lessons: Assessing a ship has adequate stability for its intended voyage on completion of cargo operations and before it sails is a fundamental principle of seamanship that must not be neglected. Sufficient time must be made before departure for an accurate stability calculation to be completed. A loading computer is an effective and useful tool for the safe running of a ship. However, its output can only be as accurate as the information entered into it. The master has ultimate responsibility for the safety of his/her ship. This responsibility cannot be delegated to shore-based managers or charterers’ representatives

– MAIB
The ship's stability did not meet minimum international requirements Credit: MAIB
Chaos on board the ship after the grounding Credit: MAIB

The MAIB’s investigation found that Hoegh Osaka’s stability did not meet the minimum international requirements for ships proceeding to sea. The cargo loading plan had not been adjusted for a change to the ship’s usual journey pattern and the number of vehicles due to be loaded according to the pre stowage plan was significantly different from than that of the final tally. The estimated weight of cargo was also less than the actual weight. Crucially, the assumed distribution of ballast on board, bore no resemblance to reality, which resulted in the ship leaving Southampton with a higher centre of gravity than normal.

This accident is a stark reminder of what can happen when shortcuts are taken in the interest of expediency. It is therefore imperative that working practices adopted by the car carrier industry ensure that there is always sufficient time and that accurate data is available on completion of cargo operations to enable the stability of such vessels to be properly calculated before departure.

– Steve Clinch, Chief Inspector of Marine Accidents