Businesses in mechanical engineering design, make, install and maintain machinery, equipment and mechanical components for industrial, commercial and other applications. Work may include fabrication, machining, assembly, repairs, maintenance, plant upgrades and the production of parts to technical drawings or specifications. Customers may also use these firms for engineering design, prototyping, testing and advice on improving the performance or reliability of equipment. Marine engineering businesses work on vessels and the machinery and systems used aboard them. Services can include maintenance and repair of engines, propulsion, steering, pumps, generators and onboard equipment, as well as refitting, fabrication and installation work. Some firms specialise in particular vessel types, marine components or shore-based support for vessels and operators.