The US Maritime Administration (MARAD) is an agency within the US Department of Transportation tasked with promoting waterborne transportation, including port and vessel operations and environmental safety. MARAD also provides crucial information in the form of primers and reports to ship owners and operators. These publications focus on the potential impacts of upcoming regulatory or other changes to marine vessel operation. Under the guidance of MARAD, Oak Ridge National Laboratory has been tasked to develop a primer that can be shared with vessel owners and operators with emphasis on the impacts of the 2020 sulfur regulations on engines, fuels, lubricants, and all related systems. The impacts of past and future fuel-related regulations and other information pertinent to the short-term future of shipping are also included.