1653. A ship that, at any time, operates seaward of the outermost boundary of the territorial sea is required to prepare, submit, and maintain a (n) __________.

Ships operating beyond the territorial sea must maintain a shipboard oil pollution emergency plan as mandated by MARPOL and 33 CFR 151.26 to ensure preparedness for oil pollution incidents, outlining onboard procedures and contact information for immediate response to spills or potential discharges.