Chief Engineer (Unlimited).is an advanced-level merchant mariner credential. The general requirements for this credential are TWIC Card (Identification, Fingerprints, Citizenship, Social Security number, etc), CG-719B Application, NDR Consent & Check, Oath, 3 letters of recommendation, photograph (supplied by TSA), SSEB Screening complete, age of 21 or over, CG-719K Physical Exam, Medical Tab in MMLD, Drug Testing Compliance, Mariner Fees, and Sea Service Letters or Discharges. Sea service requirements include recency- 90 days in the past 3 years on vessels of appropriate horsepower, Chief Engineer- 360 days of service as an 1st A/E, or 360 days of service while holding a MMC as 1st A/E, of which 180 days of service as 1st A/E, and service as an assistant engineer is accepted on a 2 for 1 basis up to 180 days. There are also propulsion and horsepower requirements. Other requirements include completing a First Aid course, CPR course, and approved firefighting courses. All candidates must complete an examination.