Maritime Legal Update – August 2026
Demurrage claims and the Pumping Warranty –
when cargo pump performance determines liability for delay
Firm note – tanker charterparties, demurrage
and laytime
The Law
Office actively advises shipowners, charterers, shippers, tanker operators,
commodity traders and P&I Clubs regarding: tanker charterparties, laytime, demurrage,
pumping warranties, voyage charters, cargo operations, and disputes arising
from tanker operations.
One of the
most frequent causes of demurrage disputes in tanker shipping concerns
allegations that cargo operations were delayed because the vessel failed to
meet its contractual Pumping Warranty.
1. Introduction – What is a Pumping Warranty?
Most tanker
voyage charterparties contain a Pumping Warranty Clause specifying the minimum
cargo pump performance expected from the vessel.
Its purpose
is to: minimise port delays, facilitate efficient discharge operations, and
allocate responsibility for discharge delays.
2. Demurrage – a reminder
Demurrage is the contractual compensation
payable to the shipowner where cargo operations exceed the agreed laytime.
Where
discharge takes longer than contractually allowed, the owner may claim
demurrage.
Charterers
frequently argue that delay resulted from inadequate pump performance rather
than circumstances beyond the vessel’s control.
3. What does the Pumping Warranty actually
require?
A typical
pumping warranty specifies: minimum pumping capacity, operating conditions, and
owner obligations.
The
critical legal question is whether the owner guarantees a particular discharge
rate under all circumstances or merely warrants that the pumping equipment is
capable of achieving that rate under appropriate conditions.
4. Not every delay constitutes breach
Britannia
emphasises that slower discharge does not automatically establish breach of the
pumping warranty.
Actual
discharge performance may also depend upon: terminal capacity, shore
back-pressure, pipeline dimensions, safety restrictions, cargo characteristics,
cargo temperature, viscosity, and operational coordination between ship and
terminal.
Each case
therefore requires careful factual and technical analysis.
5. Burden of proof
Successful
demurrage claims depend upon demonstrating the true cause of delay.
Owners
should establish that: pumping systems functioned properly, equipment was fully
operational, discharge was conducted correctly, and any restrictions arose from
external circumstances.
Conversely,
charterers disputing demurrage must demonstrate that delay was caused by
inadequate vessel pump performance.
6. Importance of operational records
The outcome
of many disputes depends upon documentary evidence including: Statement of
Facts, Pumping Log, Cargo Log, terminal records, pressure records, engine room
records, and correspondence with the terminal.
Technical
records frequently determine the outcome of demurrage disputes.
7. Practical implications for owners
Owners
should ensure: proper maintenance of pumping equipment, accurate operational
recording, documentation of terminal restrictions, and prompt notification of
any external factors affecting discharge performance.
Comprehensive
records often provide the strongest defence of demurrage claims.
8. Practical implications for charterers and
shippers
For
charterers and shippers, a longer discharge operation does not automatically
justify rejection of demurrage.
Consideration
should also be given to: terminal readiness, shore-side constraints, and
whether the pumping warranty was actually breached.
Ultimately,
liability depends upon both the contractual wording and the factual
circumstances.
9. Law Office conclusions
Disputes
concerning Pumping Warranties remain among the most common tanker charterparty
disputes.
Key
practical lessons include: careful drafting of pumping warranty clauses, comprehensive
operational documentation, proper technical investigation of discharge delays, and
preservation of complete discharge records.
In
practice, successful demurrage claims frequently depend less on the duration of
discharge than on proving why the discharge actually took longer than
contractually agreed.