[13] A port is a place equiped to facilitate the necessary relations between ships, as agencies of sea transport, and the land. ... The commecial port can also undertake the maintenance of the ships which use it , but its more usual function is to make possible, by means of special equipment in the form of quays,e tc., the passage of goods, mails and passengers between ship and ashore. For that purpose ports must have shelter against winds, waves and swell.