The Office of Design and Engineering Standards issued Policy Letter No. 02-19 “Design Guidance for Lithium-Ion Battery Installations Onboard Commercial Vessels” to improve the plan approval process for commercial vessel propulsion or electrical systems powered by installed Lithium-ion batteries. The policy does not apply to the carriage of Li-ion batteries as cargo or portable devices with Li-ion batteries that are not permanently installed on the vessel.
Source: USCG
Link: Design guidance for commercial vessels using Lithium-Ion batteries for propulsion or electrical systems