A Declaration of Security (DOS) is a declaration that addresses the security requirements that could be shared between a port facility and a ship (or between ships) and will state the responsibility for security each shall take.
It is an agreement between both partieS. The DoS is effectively a contract between a ship and a port facility or a ship and another ship that confirms the security responsibilities of each party during the ship/ship interface or ship/port interface. On an operational basis, a DoS may be requested by either a PFSO or SSO within the terms of the ISPS code.
Ships must have available copies of any DoS from the last ten calls at port facilities (including ship-to-ship interfaces) for inspection by officers duly authorised by a port facility’s Government. This should be kept with any other information about its last ten
calls at port facilities (see ISPS Code Part B paragraphs 4.37 and 4.38).