Sea NG - Compressed Natural Gas Transportation Leaders Coselle homepage Sea NG is a world leader in marine CNG or compressed natural gas transportation. Over the past decade, Sea NG has developed the Coselle System and has designed ships that integrate Coselle technology into the hull in order to safely, efficiently and economically transport gas over medium distances. Sea NG built on over a decade of design, engineering and testing to develop a project-ready marine CNG transportation system. Sea NG has a range of construction-ready ship designs that integrate Coselle technology to address a wide range of customer gas delivery requirements. The Sea NG compressed natural gas transportation system is a simple yet flexible and lower cost alternative to other midstream gas transport technologies.