Part 156 of the Code of Federal Regulations, which governs oil transfer operations, specifically outlines regulations to minimize the risk of spills during the transfer of oil between vessels and from vessels to shore facilities. The regulations primarily target commercial vessels and those engaged in oil transportation operations.
Public vessels are typically defined as government-owned ships used for non-commercial purposes, such as military or research missions. Because these vessels do not engage in commercial activities that involve oil transfer in the same manner as private or charter vessels, they are generally exempt from the comprehensive requirements set forth in Part 156. This means that while the regulations apply to vessels engaged in commercial operations, public vessels, given their specific operational context, have different regulatory standards that do not include the same stringent measures for oil transfers.
In contrast, private vessels, recreational vessels, and charter vessels are typically subject to these regulations as they are involved in the transportation of oil in some capacity. Therefore, the correct answer reflects the understanding of how the regulations under Part 156 are designed with respect to the nature and purpose of the vessel's operation.