Page 374 - Practical Ship Design

Freeboard und Subdivision 33 1

In the case of the HSS1500, those making the safety case assessment identified
I09 potential hazards which for convenience were classified under four headings:
Common potential hazards
Fire in the engine room; collision with another ship; failure of life-saving
appliances; fuel leakage from vehicles on board.
Less common potential hazards
Bow thruster malfunction; mooring equipment failure; vehicle falling into
the water during loadinghnloading; collision with submerged object;
dangerous goods.
Rare potential hazards
Legionnaire’s disease from air conditioning; ballast systems failure; block-
age of water jet; landing stage failure; food poisoning; leakage during
bunkering operation.
Human-related potential hazards
Navigation error; person overboard; navigation warnings not received.
The likelihood of each type of risk occurring were assessed under five headings:
Scale 1 - Frequent
Scale 2 - Reasonably probable
Scale 3 - Remote
Scale 4 - Extremely remote
Scale 5 - Extremely improbable

The effect of each hazard were classified under four headings:
Scale A - Minor effect
Scale B - Major effect
Scale C - Hazardous effect
Scale D - Catastrophe
The interaction between the probability of an occurrence and the seriousness of the
effect produced by it is tabled as a matrix with three regions: intolerable, tolerable
and negligible.
Whilst there is clearly a need for good quantitative data if reliance is to be placed
on assessments of this sort, even without such data the posing of these questions
seems bound to improve decision making and safety.