Contracts and charterparties sometimes contain phrases that look harmless.
according to the custom of the port
as customary
according to usual trade practice
notices to be accepted as per port practice
During negotiations, wording like this feels convenient. Commercial adults are negotiating; everyone supposedly understands how the port works. Why spell out the obvious?
The problem starts when the “obvious” turns out to mean different things to each side.
One party says the notice was tendered in time. The other says: no, notices are not accepted that way under the practice of this port.
One party thinks loading or discharge should proceed “normally”. The other answers: normal here means this - slow, inconvenient, and shaped by local features you only discover when expected demurrage starts looking suspiciously like despatch.
Local holidays belong in the same category.
The contract may look clear. Then, at the critical moment, the port or terminal is closed because of a local holiday.
You should have allowed for local practice. That is how it works here.
From that point, the dispute is no longer about an elegant contractual phrase. It is about what counts as usual practice, which days are working days, how time is calculated, and who should have checked all of this before signing.
There is an unpleasant surprise here: custom must be proved.
Not by emotion. Not by saying “everyone does it”. By evidence.
The classic example is Postlethwaite v Freeland, a House of Lords decision from 1880.
Yes, 1880.
As we noted recently, under English law an old precedent is not a museum exhibit. It can still be a working tool.
In that case, the charterparty required discharge:
with all despatch according to the custom of the port
The cargo was discharged by lighters. The lighters were controlled by one company and supplied to vessels in turn. The vessel was delayed for about 31 days because the port was congested and there were not enough lighters.
The shipowner tried to recover money from the charterer for the delay.
It failed.
The House of Lords held that, where the parties had tied discharge to the custom of the port, the actual practice and circumstances of that port had to be considered.
The charterer had acted within the ordinary port system. The delay was therefore not shifted onto him.
If a contract refers to custom, customary practice, port practice or local holidays, do not treat that wording as decoration.
If you do not understand what stands behind the local practice, you have not really agreed the condition.
You have agreed a future dispute about what it means.
Working days, holidays, the mechanics of notices and the effect of port practice should be spelled out directly - or at least checked before signing, not after the clock has started running.
A reference to “usual practice” sometimes opens not a door to flexibility, but a rabbit hole.