Security for charges
31. The Company may require a person who incurs or is about to incur a charge to deposit with, or to guarantee, such sum of money as is, in the opinion of the Company, reasonable having regard to the amount or probable amount of the charge, and where such a person fails to deposit or guarantee the sum of money required by the Company, the Company may detain the vessel in the harbour or goods on or in harbour premises, in respect of which the charge has been or will be incurred, until the requirement has been complied with or the charge paid.