When ships call at ports, manoeuvrability can often be limited and the master of a ship may be unfamiliar with port environs. To ensure that the ship reaches and departs from its berth safely, ports’ employ the services of a towage company that operates Tugs. Towage is an important element in the safe and efficient operation of ports around the world, with thousands of daily vessel movements being assisted by a huge international fleet of tugs. Designed to manipulate or lead the movement of large ships or barges, these small, but comparatively powerful tugs make the act of pushing and pulling large merchant ships look easy. In fact, the skill lies in hands of the experience at the helm of the tug combined with extremely powerful engines. These engines give tugs high bollard pulls, but not at the expense of manoeuvrability. Pusher tugs are also used to push long trains of barges on rivers and inland waterways in the US, while ocean going tugs are a front-line resource and can be involved in salvage, rescue, fire-fighting and pollution prevention. Operations can be as diverse as providing assistance to ships in distress to towing oil rigs.