The meaning of the word day may be interpreted as days upon which it is customary to work. However, lay time may be expressed in terms of a number of working days. In shipping business, during charter-party negotiations, prudent shipbokers do not leave such things to chance and include a reference to working days in charter-party clauses.
Working day expression makes it clear that customary rest days and holidays do not count as lay time. For example, working day expression exclude Fridays in Islamic countries. The expression working day is a description of the type of day. Working day expression is intended to draw a distinction between those days upon which work is habitually carried out at the port in question and those days which are considered to be days of rest or holidays. Working days is a day of 24 consecutive hours. Working day expression does not take into account the number of hours which are customarily worked at that port in any working day. Therefore, working day expression would not be open to the charterer to construe a clause in such a way that working day meant a period of 24 hours consisting of two calendar days during which at the relevant port it was customary to work for 12 hours a day.
In theory, working day is a period of 24 hours which starts at midnight on one day and finishes at midnight on the following day i.e. a working calendar day.
Mere reference to days will be calendar days unless there is something which makes it clear that the intention was that it should be any period of 24 hours. In circumstances where working days do not commence at midnight, it is likely that before the expiry of a working day consisting of a period of 24 hours, a non-working day such as a holiday or a Sunday may begin. If that occurs, the working day will then effectively be in two (2) parts:
- First part being from the commencement of lay time to midnight on that day
- Second part being at midnight at the end of the holiday until the expiry of the 24 hours
For example, if charter-party laytime provision is for working days and Sunday is excluded (a non-working day in port). When laytime commences at noon on Saturday, the first day of allowed laytime will run for 12 hours until midnight on the Saturday. Laytime will be interrupted for during Sunday i.e. 24 hours. Laytime will resume for a further 12 hours ending at noon on Monday.