Obligations of a shipowner and a merchant were mutually absolute – the former shall reach place or places named in contract, there load the goods and deliver them to the receiver. The latter shall provide for the goods and pay freight.
Per Kennedy LJ in Leonis Steamship Company, Limited v Rank, Limited  1 K.B. 499 at p.519:
The limits of a port established by law or ancient custom may be very wide; or, again, in the case of a newly-established place of shipping traffic, the limits may be uncertain because not yet defined by any competent authority. The ports of London and Liverpool are instances of the first class; for aught I know Bahia Blanca may be an instance of the second. … In the case of a port, and nothing more, being designated in a charterparty as the point of destination our Courts have acted in accordance with those dictates of reason and practical expediency which ought to be paramount especially in the region of mercantile business. Just as a port may have one set of limits, if viewed geographically, and another for fiscal or for pilotage purposes, so when it is named in a commercial document, and for commercial purposes, the term is to be construed in a commercial sense in relation to the objects of the particular transaction.
Hall Bros Steamship Co, Ltd v R and W Paul, Ltd [1914-15] All ER Rep 234 per Sankey J at p.236:
In my opinion the term "port" in a charterparty is to be taken in its commercial sense, and is not to be defined by the meaning given to it by the legislature in Acts passed for such entirely different objects as pilotage or revenue. Any doubt or controversy on the point must now be taken as settled in Leonis Steamship Co, Ltd v Rank, Ltd.