Since the length of the working shift is assumed as 12 hours,
the remaining time in the shift after the ‘Travel time’ is deducted is
the summation of ‘Productive time’ and ‘Non-productive time’. The
‘Non-productive time’ is the period, which the climate conditions
and the daylight hour limitation causes delays and therefore CTVs
stay at the port. The ‘Productive time’, which the technicians can
perform the actual repairs, is the remaining period after ‘Travel
time’ and ‘Non-productive time’ values are deducted from the
length of the working shift.