108
Sensemaking in Safety Critical and Complex Situations
there was something unexpected with the behavior of the vessel and interfered. On
Sjoborg a number of abnormalities have been accepted as “ normal” and acknowledged by the crew. Further investigations revealed that the underlying causes were
poor installation of equipment components causing network failure, in combination
with alarms that were challenging to understand. Loss of network frequency measurement on the main switchboard activated the load-reduction mode, limiting the
thruster output to only 15%. Nonconformity between DP commands and feedback
from the thrusters took place, ended up in automatic shutdown of the thrusters, leading the vessel off course. Then the crew realized the problem and tried to interfere.
But, it was too late. Thus, there is a question related to controllability and safety of
the design of the control system. It is difficult for the crew to detect any peculiarities
behind their screens, especially those related to digitalization. When warnings and
alarms have become so common it becomes improbable for the crew to distinguish
the safety-critical message. The crew can recognize that there is something wrong
with their system when a more perceptible sign takes place, like power cut.
The alarms were probably not designed in accordance with accepted best practices alarm standards such as EEMUA 191 ( EEMUA, 2013). The understanding of
the alarms, alarm text description and design of the systems should be improved if
human factors design standards had been followed.
QUANTITATIVE SURVEY OF HUMAN FACTORS IN SHIP DESIGN
Following up the field research that was conducted on the two OSVs in the Norwegian
Sea described a quantitative survey was performed and reported ( Rumawas &
Asbjørnslett, 2015a, 2015b, 2016). Questionnaires and daily diaries were developed
based on the existing human factors framework published by the LR ( 2009). Several
factors like noise, temperature and motion were recorded. The survey revealed that
the elements of “ human factors” in ship design are quantifiable and measurable. It
indicates that design can have a substantial influence on human factors assessment
especially in habitability and workability. Good habitability of ship could reduce
motion sickness incidence, fatigue and sleep disturbances on board. In turn, all these
influence the operator’s performance.
It is also revealed that some of the existing standards that govern noise ( Det
Norske Veritas, 2009b; International Maritime Organisation, 1981), motion and slamming ( Graham, 1990; NATO, 2000; NORDFORSK, 1987) are too lax that neither
they influence comfort nor safety. For example, the highest noise level measured in
the cabin on OSV A was 56.7 dB ( A) while on DP operation. Standard regulation in
Norway defines that noise in work areas should be lower than 55 dB, and to avoid sleep
disturbance, indoor guideline values for bedrooms are 30 dB L Aeq for continuous noise
and 45 dB L Amax for single sound e vents – ref WHO ( World Health Organization)
( Berglund, Lindvall, & Schwela, 2009). The noise level conditions inside the cabin
were uncomfortable due to a high level of screeching noise produced by the bow
thrusters located not too far away. It was difficult for normal people to sleep in such
a condition. The standards for seafarers allow noise level up to 60 dB ( A) in cabins.
Another example, the operation criteria related to motion allows “ heavy manual work” to be done when the vessel undergoes a vertical acceleration up to 0.15 g
Sensemaking in Safety Critical and Complex Situations
there was something unexpected with the behavior of the vessel and interfered. On
Sjoborg a number of abnormalities have been accepted as “ normal” and acknowledged by the crew. Further investigations revealed that the underlying causes were
poor installation of equipment components causing network failure, in combination
with alarms that were challenging to understand. Loss of network frequency measurement on the main switchboard activated the load-reduction mode, limiting the
thruster output to only 15%. Nonconformity between DP commands and feedback
from the thrusters took place, ended up in automatic shutdown of the thrusters, leading the vessel off course. Then the crew realized the problem and tried to interfere.
But, it was too late. Thus, there is a question related to controllability and safety of
the design of the control system. It is difficult for the crew to detect any peculiarities
behind their screens, especially those related to digitalization. When warnings and
alarms have become so common it becomes improbable for the crew to distinguish
the safety-critical message. The crew can recognize that there is something wrong
with their system when a more perceptible sign takes place, like power cut.
The alarms were probably not designed in accordance with accepted best practices alarm standards such as EEMUA 191 ( EEMUA, 2013). The understanding of
the alarms, alarm text description and design of the systems should be improved if
human factors design standards had been followed.
QUANTITATIVE SURVEY OF HUMAN FACTORS IN SHIP DESIGN
Following up the field research that was conducted on the two OSVs in the Norwegian
Sea described a quantitative survey was performed and reported ( Rumawas &
Asbjørnslett, 2015a, 2015b, 2016). Questionnaires and daily diaries were developed
based on the existing human factors framework published by the LR ( 2009). Several
factors like noise, temperature and motion were recorded. The survey revealed that
the elements of “ human factors” in ship design are quantifiable and measurable. It
indicates that design can have a substantial influence on human factors assessment
especially in habitability and workability. Good habitability of ship could reduce
motion sickness incidence, fatigue and sleep disturbances on board. In turn, all these
influence the operator’s performance.
It is also revealed that some of the existing standards that govern noise ( Det
Norske Veritas, 2009b; International Maritime Organisation, 1981), motion and slamming ( Graham, 1990; NATO, 2000; NORDFORSK, 1987) are too lax that neither
they influence comfort nor safety. For example, the highest noise level measured in
the cabin on OSV A was 56.7 dB ( A) while on DP operation. Standard regulation in
Norway defines that noise in work areas should be lower than 55 dB, and to avoid sleep
disturbance, indoor guideline values for bedrooms are 30 dB L Aeq for continuous noise
and 45 dB L Amax for single sound e vents – ref WHO ( World Health Organization)
( Berglund, Lindvall, & Schwela, 2009). The noise level conditions inside the cabin
were uncomfortable due to a high level of screeching noise produced by the bow
thrusters located not too far away. It was difficult for normal people to sleep in such
a condition. The standards for seafarers allow noise level up to 60 dB ( A) in cabins.
Another example, the operation criteria related to motion allows “ heavy manual work” to be done when the vessel undergoes a vertical acceleration up to 0.15 g