Can a ship be arrested for an unpaid debt?

Potentially, yes. The Admiralty Act 1973 gives the High Court jurisdiction over certain maritime claims, including claims for goods or materials supplied to a ship, such as bunkers and repairs, and it allows the arrest of a ship in some cases through an action in rem. The court's arrest procedure involves applying for a warrant, providing an affidavit and often giving an undertaking as to damages in case the arrest proves wrongful. The claim must fall within the categories in the Act, and the ship arrested must generally be one that is connected to the claim in the way the Act specifies. Act quickly as ships move on, and take specialist advice about jurisdiction, security and the possibility of a maritime lien. Keep the invoices, delivery notes and contracts, and consider notifying the port authority.