Loss of the Baltic Ace

The shipping media is reporting the tragic loss of the PCCT 'Baltic Ace' off Rotterdam, in which 11 of her crew lost their lives. What was notable about the collision and sinking was the huge loss of life - almost half the crew. In 2012, sinkings are usually a relatively drawn out affair with the crew able to abandon ship in lifeboats or liferafts. 'Baltic Ace' is reported to have sunk within 15 minutes of the collision.

m/v Baltic Ace (photo: www.FleetMon.com)

The website 'VesselFinder.com' has uploaded a video of Baltic Ace AIS data, showing 'Baltic Ace' as the 'stand on vessel' and 'Corvus J as being the 'giveway vessel'. 'Corvus J' alters course to starboard to pass astern of 'Baltic Ace', but then 'Baltic Ace' appears to alter course to port whereby 'Corvus J' hits 'Baltic Ace' in her starboard side. AM can't attributed any blame to either vessel - this is just what the Collision Regulations state for crossing vessels.

gCaptain is also reporting daily on the casualty and have photos of damage to 'Corvus J's bulbous bow after the collision. 'Baltic Ace lies on her side in 36 metres of water (her beam is 25 metres), salvors have been appointed to remove her bunkers and a diver's search for the bodies of the missing crew is underway.

The result of the collision is eerily similar to the loss of Wilhelmsen's 'Tricolor'. Pure Car and Truck Carriers are essentially floating car parks, designed with as many large area decks and as few watertight bulkheads as can be allowed under Class Rules. Combined with high freeboard and a tender stability, water in the wrong places has rapid and dramatic consequences.

The fact that the collision lead to rapid flooding and loss of stability in a modern, 2007-built vessel will hopefully spur the IMO and Classification Societies to review why PCCT's have such relatively poor survivability. The crews of bulk carriers and Roll on/Roll off ferries have all benefited (eventually) from design changes after high profile casualties with large losses of life.

The Antipodean Mariner

Passenger ships and the SOLAS Convention

The Antipodean Mariner is shocked at the loss of the Costa Concordia on a voyage that the vessel has completed safely on a weekly schedule.

One of the readers comments asks how she could capsize to starboard after grounding in her port side?

Passenger ships are regulated by a more stringent chapter of the SOLAS Convention, the safety code regulating shipping. Passenger ships are designed to survive damage that would sink a cargo ship by having more watertight bulkheads.

There are two naval architectural principles applied to passenger ships under SOLAS.

The first is that of the margin line, an imaginary line up to which the watertight bulkheads must extend, so that if the prescribed number of watertight compartments are flooded, water will not flow over the top of the bulkhead into the adjacent dry compartment. The margin line the margin of safety.

The second principle is that passenger ships, if they are going to sink, do so on an even keel. To achieve this, they are fitted with cross-flooding valves to equalise list.

Costa Concordia suffered huge damage as a consequence of the grounding - the rock embedded in the ship's port side is evidence of this. To have sunk means that more than the 'survivable' number of compartments were breached and the margin line was submerged. To have listed to starboard means she became unstable as she sank, which is not what she was designed to do.

No passenger ship the size of Costa Concordia has ever sunk.  The Antipodean Mariner speculates that the investigation will focus on why she rolled over and what the impact of an open water sinking could have on the fleet of super-cruise ships in service. The loss of life is tragic, but thousands may have died if Costa Concordia had not rolled on to an island outcrop.

This high visibility of this casualty will result in a very public inquiry into the adequacy of the passenger ship stability provisions of SOLAS.

The Antipodean Mariner