Following the terrorist attacks on the United States in 2001, the issue of maritime security became the third mandate of the International Maritime Organization (IMO), alongside safety and pollution prevention. On December 12, 2002, the International Ship and Port Facility Security (ISPS) Code was adopted to implement measures and procedures to prevent acts of terrorism that threaten the security of passengers, crews, ships and port facilities.
In order to implement these measures expediently, they took effect through amendments to Chapter XI of the SOLAS Convention. Chapter XI was modified to create Chapter XI-1, for existing provisions, and the new Chapter XI-2, "Special Measures to Enhance Maritime Security", to implement the ISPS Code.
The provisions apply to cargo ships of 500GT and above and to all passenger ships. These apply equally to pleasure yachts when engaged in trade by carrying fare-paying passengers or engaged in other commercial activities.
Work relating to the approval of the Ship Security Assessment (SSA), the Ship Security Plan (SSP), onboard verifications and the statutory certification is not normally delegated to a Recognized Security Organization (RSO). However, a RSO may assist ship owners or operators in the preparation of their SSA and SSP.
On board security audits are carried out at approximately 30 month intervals and are usually scheduled to coincide with the audits and inspections required for the ISM Code and the Maritime Labour Convention 2006.