Section 140.205 - General vessel operation(a) A vessel must be operated in accordance with applicable laws and regulations and in such a manner as to afford protection against hazards to life, property, and the environment.(b) Towing vessels with a Towing Safety Management System (TSMS) must be operated in accordance with the TSMS applicable to the vessel.(c) Vessels must be manned in accordance with the COI. Manning requirements are contained in part 15 of this chapter.(d) Each crewmember that is required to hold a Merchant Mariner Credential (MMC) must have the credential on board and available for examination at all times when the vessel is operating.(e) All individuals who are not required to hold an MMC permitted onboard the vessel must have and present on request a valid personal identification that meets the requirements set forth in 33 CFR 101.515 .