MDX academic Roger Kline, who will appear in an upcoming Channel 5 documentary on the sinking of The Herald of Free Enterprise, explains what caused the disaster.
The sinking of the Herald of Free Enterprise on March 6th 1987 with the loss of 198 lives was an accident waiting to happen, highlighting the devastating consequences of abandoning safe working practices in the name of financial savings.
The issue of human factors in such disastrous events began to gain serious attention after the tragedy.
Human factor is the scientific discipline concerned with understanding how we interact with each other and with other elements of a system.
In turn systems are then designed to optimise well-being and performance among humans – and reduce safety risks.
The Herald sinking was avoidable had steps recommended by maritime inquiries and the ship owners Townsend Thoresen’s own captains been adopted.
It is now a case study in how such disasters could be avoided.
These were the main causes:
Firstly, Roll On – Roll Off (RoRo) ferries were inherently unstable
An official investigation into the sinking of the European Gateway ferry, which had a similar design to the Herald warned of another potential tragedy.
The 1986 European Gateway inquiry identified a new phenomenon, “transient asymmetric flooding”, to account in part for the rapid capsizing.
Unlike other ships, which are subdivided into watertight compartments, the vehicle decks of RoRo vessels meant any flooding on these decks would allow the water to flow the length of the ship.
It was known prior to the Herald disaster that RoRo ships lost in collisions sank or capsized within ten minutes.
They were uniquely dangerous because their design features for quick loading led to high sided ships and lack of internal bulkheads which made the ships top heavy and vulnerable to a sudden rush of water through the bow or stern doors.
The company knew about the dangers.
Six years previously officers on its sister ship the Spirit of Free Enterprise threatened to strike unless safety standards improved, and in particular demanded a third officer to close the ship’s bow doors.
The owners insisted that only two officers were needed to simultaneously close the bow doors, let go the stern ropes and assist the captain on the bridge.
Secondly, the culture of the shipping line was rotten
Mr Justice Sheen summed up his findings at the subsequent Herald of Free Enterprise inquiry as “from top to bottom, the body corporate was infected with the disease of sloppiness”.
The inquiry identified a number of examples.
Ever since it had launched six years previously The Herald of Free Enterprise suffered from a permanent list, while repeated complaints from captains were ignored and it was forced to sail with a ballast tank permanently full of water to counter the list – which lowered the ship’s bow.
This was compounded at Zeebrugge harbour because other ballast tanks were filled at its low dock to allow car drivers to off load.
The time to empty these tanks was longer than the harbour turnaround time low dock to offload. The company was asked by its captains to fit pumps to clear the water more quickly but refused saying the cost was too high – £25,000.
One root cause was the failure of the assistant boatswain to close the bow door before dropping moorings, after he fell asleep on duty due to fatigue from working an excessively long shift.
The bow door remained open as the ferry set sail, the decks became flooded and the boat filled with water and capsized minutes later.
A crucial contributory factor was the absence of an indicator that the bow door was open.
As a result, the captain had no view of the bow door and no indicator light or other means for him to confirm they were closed. The absence of a communication channel with deck crew meant the captain had to make assumptions about the status of the rear door.
The company had dismissed requests by its captains to have an indicator installed on the bridge showing the position of the doors, partly because the company thought it frivolous “to spend money on equipment to indicate if employees had failed to do their job correctly.”
There was also pressure to remain on schedule and a clear deficiency in safety leadership at a higher level in the organisation.
There was one final contributory factor.
When a vessel is under way, the movement under it creates low pressure, which has the effect of increasing the vessel’s draught.
In deep water the effect is small but in shallow water it is greater, because as the water passes underneath it moves faster and causes the draught to increase. This reduced the clearance between the bow doors and water line to less than two metres.
After extensive tests, the investigators found when the ship travelled at a speed of 18 knots (33 km/h), the wave was enough to engulf the bow doors.
The relevance of human factors science
Human factors science tells us human beings make mistakes and any potentially unsafe system (all systems) needs to build in safety measures to anticipate that.
We had here an inherently unsafe type of ship with staff working 24 hours shift and poor communication channels. It was a lethal system.
Working 24-hour shifts increases the risk of mistakes by staff which was compounded because the captain had no warning of such errors.
The captain had no time to take corrective measures after the mistakes because this ship capsized in 90 seconds due to its design.
This free surface water is mirrored when carrying a tray full of water and the risk was foreseen in the RoRo ferry disaster inquiries.
In total, 198 crew and passengers paid with their lives for this disastrous failure to address predictable safety risks. The relentless pursuit of profit was a major contributory factor and continues to this day on ferries.
A year after the disaster, many cross-channel seafarers, including some who had played heroic roles saving lives in the Herald, were sacked by new owners P&O after protesting about longer hours and worse conditions.
Then some 23 years later, earlier this year, P&O’s new owners sacked their replacement crews for even cheaper ones, and got away with it as government ministers blustered and sat on their hands.
Human factors science learned from the Herald disaster and is widely applied in sectors as diverse as nuclear power stations and healthcare but the working culture of some shipping lines has not changed.
Roger Kline is a Research Fellow at Middlesex University and advised the Herald seafarers when they were dismissed by P&O in 1988.
If you are interested in knowing more about Human Factors at work, Roger recommends Steven Shorrock’s excellent book Human Factors and Ergonomics in Practice: Improving System Performance and Human Well-Being in the Real World (2016).
The documentary ‘Why Ships Sink: The Herald of Free Enterprise’ will air at 9pm on Channel Five on Sunday October 20th