Helge Ingstad and Lines of Defense


#1

An interesting thing about the Helge Ingstad is that two important aspects of the incident, the AIS and flooding are at completely different levels of safety defense.

It could be likened to sports, a soccer game for example.

First line of defense is to keep the ball in your possession and at the opponents end of the field. That would be keeping the AIS on.

Excess speed, then lack of situational awareness - the other team gains possession and works the ball down the field.

The last line of defense is the goal keeper stopping shots on goal. Last ditch defense. That would things like emergency generators then last, watertight integrity. In this case the failure of the watertight compartments breached the last defense.


#2

Electrical power on a ship is important.

Typically at sea one generator is kept on-line while a second is on stand-by, ready to start automatically if the on-line generator fails for any reason. The third generator is either undergoing maintenance or is the second back-up, in case the generator on back-up fails to start or go on-line.

This system is very robust and rarely fails (YMMV). When it does fail it’s a result of multiple errors of various types, communication failure, bad line up, equipment failure. Always a surprise, never the same story.

But waiting in the wings is the emergency generator, the next line of defense, when some unanticipated combination of errors or oversights causes all three of the ship’s generators to fail to take the load.

The last two lines of defense are the emergency generator and the batteries. Sometimes get less attention then they deserve because they are rarely the front lines of the battle.


#3

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#4

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#5

It’s a good analogue.

You could also think of “active” and “passive” safety: the former refers to what the crew does to avoid the incident and, if unsuccessful despite their best efforts, mitigate the consequences, and the latter to general design, structural strength, watertight integrity, vessel systems etc. that should be in place and (in case of automated system) function without action from crew. It’s not entirely unlike in a car crash: the driver is responsible for avoiding obstacles, but if unsuccessful, then it’s up to the crumble zones, airbags, seat belts etc. to keep everyone alive.


#6

Many of the risk assessment systems speak of “preventive” controls and “mitigating” controls. That basic outlook could be applied to ship design - if an owner is willing to look beyond class or flag only requirements.


#7

Another point is everyone involved is working with restraints, time, money, information, understanding, none are available in unlimited quatites.

The officer who made the decision to come left at the last minute was working within very tight time limits and with very limited or flawed understanding of the situation.

Likewise the people that set the AIS policy might have benefited from an in depth study. The designer of the shaft seals likewise perhaps. Workers at the shipyard don’t have the luxury unlimited time and resources.

That’s the case with the emergency generator I’ve noticed. If the battle with the generators in the engine room is won each day there’s not much time or energy left over for the EDG.

The emergency generator is important, but not urgent. Work on the ship’s service generators can be at times both urgent and important.