Electric Drive Propulsion Systems News

Caterpillar Marine informs it has begin a dual fuel engine retrofit conversion onboard the 472-foot Fure West tanker, owned by Furetank Rederi A/B. The MaK M 43 C diesel engine onboard the tanker will be retrofitted in hull to the seven-cylinder M 46 dual fuel platform, with each cylinder offering 900 kW of rated power. Additionally, Caterpillar is also supplying the complete gas system for the tanker, including bunker stations, two LNG tanks measuring 4.15 meters by 24 meters and the vaporizer.

Caterpillar Marine successfully completed the commercial marine industry’s first dual fuel engine retrofit conversion in hull. Performed in under six weeks, Caterpillar Marine along with Cat dealer Bolier, completed an in hull retrofit onboard the Coral Anthelia, an Anthony Veder LNG carrier vessel. The MaK™ M 43 C diesel engine was retrofitted to the 6 cylinder M 46 dual fuel platform, with each cylinder offering 900 kW of rated power. As a result of performing the retrofit within the hull, no modifications had to be done to the ship’s structure and no docking was required. “Caterpillar is firmly committed to providing sustainable, flexible solutions that enhance our customers operations.

Commercial and military users of electric propulsion systems have experienced failures of the variable frequency drive (VFD) and harmonic filter (HF) systems because the system design, including the VFD, did not have adequate self-monitoring and protection. On a ship, a variable-frequency drive (VFD) can be used to control the speed and direction of rotational motors, such as pumps, propellers and azipod systems. In some cases, these failures have resulted in catastrophic equipment failures causing arcing, fire and explosions of capacitors. In September of 2010, the Cunard Carnival cruise ship RMS Queen Mary 2 (QM2) was underway in the Mediterranean when an explosion occurred in the aft main switchboard room resulting from the failure of one of 12 capacitors in a harmonic filter…

Since Royal Caribbean decided to embrace the advanced marine propulsion technology inherent with gas turbines, power plants aboard cruise ships built and delivered in the new millennium could be much different. Even if all newbuilds do not incorporate gas turbine power, other propulsion suppliers such as diesel manufacturers will be driven by this new competitor in a previously diesel dominated domain — along by new and increasingly stringent environmental emission requirements — to continuously improve their designs in order to meet future needs. Royal Caribbean and Celebrity selected a COmbined Gas turbine and Steam turbine Electric drive System (COGES) for their new ships.

Throughout the history of shipbuilding, the key challenge too often has been how to build the right ship around a given propulsion system, rather than creating tailored propulsion system for the ship. That was true when the best propulsion "engines" available were sails, and it is also true for today's diesel, gas turbine and electric hybrid systems as well. The ideal, of course, is to allocate cargo space, cabin space, the shape of propulsion units, and even the shape of the ship's itineraries around the needs of the marketplace rather than around the limitations imposed by the ship's propulsion system. Factors that remain in the path of that ideal include the underlying efficiency across a broad operational range with which chemical energy is turned into mechanical energy…