Port State Control (PSC) as defined by wikipedia.com is the inspection of foreign ships in other national ports by PSC officers (inspectors) for the purpose of verifying that the competency of the master and officers onboard, the condition of a ship and its equipment comply with the requirements of international conventions (e.g. SOLAS, MARPOL, STCW, etc.) and that the vessel is manned and operated in compliance with applicable international law.
These controls are international standards that promote maritime safety in terms of pollution prevention and shipboard living and working conditions, they are also in place to eliminate all substandard vessels from the industry. It is in the concept of port state control that the maritime community worldwide has seen a possible solution to the problem of the substandard ship. Not the solution, but rather one of the more positive steps which can be taken - and necessary because the prime obligation of the ship-owner and his register have been too often neglected.
Most maritime authorities now have more modern, effective and direct powers of port state control inspection: SOLAS, MARPOL, the Loadline Convention, the Registration of Ships and the STCW Convention all give powers (and duties) of inspection to ensure compliance. And most states give themselves extensive powers in relation to prevention of oil pollution.
Port State Control is not a waste of state resources for one primary reason: it is now becoming nearly impossible for a ship-owner to identify one or two ports where their ships could trade without concern about a port state inspection or a fear of detention. It has been an active component of the shipping world for a considerable time, and therefore it is safe to deduce that these controls that have been put in place are achieving its purpose- “to verify that the competency of onboard personnel, the condition of a ship and its