‘Per Workable Hatch daily’: Where the terms ‘workable’, ‘working’ or ‘available hatch daily’ are introduced, complications set in. To be ‘workable’ under English Law, a hatch must be capable of being ‘worked’ – that is to say, there must be space beneath that hatch at the loading port, and there must be cargo under the hatch at discharge port. Taking the above example of the ‘HERON’, as each hatch is emptied, the discharge rate would reduce by multiples of 175 tonnes daily, until all holds become empty one by one. This is, however, a cumbersome and sometimes complicated method of calculation, and English law procedure lays down a simpler alternative which is followed in such cases. First it is necessary to establish the ‘largest’ unit of cargo in the vessel. Reference to the ‘stowage plan’ shows that 1,575 tonnes contained in No. 3 hold and tweendeck beneath No. 3 hatch constitutes the ‘largest’ unit. Thus, 1,575 tonnes ) 175 daily = 9 days laytime overall. However, where the largest unit of cargo is served by two or more hatches, the unit tonnage must be sub-divided. Assuming two hatches served No. 3 hold and tweendeck, for example, 1,575 tonnes would first be divided by 2 before applying the factor of 175 tonnes daily. In that case, the largest indivisible cargo unit would become the 1500 tonnes contained in No. 2 hold and tweendeck, and the laytime duration calculation would then be: 1,500 tonnes ) 175 daily = 8.571428 days laytime. Indefinite Laytime: Occasionally, an owner or operator will agree for his ship to be loaded or discharged as per ‘custom of the port (COP); ‘customary despatch’ (CD); ‘customary quick despatch’ (CQD), or ‘fast as can’ (FAC) terms. The common factor with these terms is that all provide a shipper or receiver with an ‘indefinite’ period during which to perform cargo operations, although they must act ‘reasonably’. It is ‘unreasonable’, for example, for cargo not to be available upon a vessel’s arrival within agreed laydays, and in such a case, the owner or operator of the ship would normally become entitled to reimbursement by ‘damages for detention’. But risk of bad weather, port congestion, and suchlike are all for the shipowner/operator to bear.