Deviation
Deviation in shipping is an unjustified departure from the agreed, customary or ordinary route of a voyage — the ship straying from the expected course or unreasonably delaying. Because the cargo owner and insurer contracted on the basis of the expected voyage, an unjustified deviation is treated seriously in carriage-of-goods and marine-insurance law.
Certain deviations are justified and permitted — notably to save life (or, within limits, property) at sea, or where reasonably necessary for the ship's or cargo's safety — and charter parties and bills of lading often contain “liberty to deviate” clauses. But an unjustified deviation can amount to a serious breach that deprives the carrier of its liability defences and limits for loss occurring during or after it, and can discharge the cargo insurer from liability. Deviation therefore links tightly to seaworthiness, the Hague-Visby Rules and cargo insurance. Understanding what counts as a permissible versus an unjustified deviation is important to carriers, shippers and insurers in managing voyage risk and cargo claims.
A ship that wanders off its expected route can lose the carrier its liability protections and even void the cargo insurance — so deviation is far more than a navigational detail. Knowing which departures are justified (saving life) and which are breaches is key to managing voyage risk, and it recurs in cargo claims and insurance disputes.
When is deviation justified?
To save life at sea (and within limits property), or where reasonably necessary for the safety of the ship or cargo; charters may also grant a "liberty to deviate".
What are the consequences of unjustified deviation?
It can strip the carrier of its liability defences and limits and discharge the cargo insurer from liability.