Transmissions for specialised applications

Italian shipyard Cantieri Navali Megaride recently commissioned Siemens Marine Solutions to equip a 65m RINA-classed OSV (offshore supply vessel) designed by Errenavi of Rome, for the Italian Coastguard. The vessel features a Siemens Siship EcoProp hybrid propulsion system.

Working with ZF Marine, its preferred gearbox supplier, Siemens is supplying a hybrid diesel and electrical propulsion system including a ZF 9300 PTI ‘hybrid-ready’ transmission and two Siemens electric motors rated 180kW at 3,000rpm with two Caterpillar 3512C diesels (1,765kW at 1,800rpm). Speed in diesel mode is around 12 knots and 8 knots in electric mode.

For this project the ZF 9300 PTI spur gear version was used which acts as a ratio multiplier, keeping the footprint of the transmission small and allowing a wide range of ratios for each transmission. The system has no boost function and no battery driven propulsion mode. Propulsion modes are diesel-only – directly through the transmission – or electric-only through the PTI (power take in).

When the ship is electrically powered in the lower load range, the efficiency of the propulsion system is increased, which can save substantial amounts of energy and fuel, with only about 10% of the main propulsion power often being required from the electric drive. As a result, such hybrid systems offer potential for increased energy efficiency, particularly for ships with frequently changing drive modes and running speeds. Running the diesel engines continually within their optimum load range not only reduces fuel consumption and emissions but also lengthens service life. In addition, longer service intervals for the diesel engines helps save money, and using electric motors in combination with diesel engines increases overall availability.

ZF sees its 9300 PTI ‘hybrid ready’ transmission as a step towards reduced CO2 emissions from marine propulsion systems as well as enabling greater fuel savings. It is part of the new 9000 series which is available in various configurations, and are suitable for engine power up to 3,700kW at 2,100rpm. ZF Marine says it can adapt existing transmissions to diesel-electric configurations.

DUTCH ERRV ORDER

ZF Marine has received an order from Dutch fleet operator Vroon for complete propulsion systems for six 50m emergency response and rescue vessels (ERRVs).

The Series 6 vessels will be operated by Vroon mainly in the North Sea area as standby ships around offshore oil installations. They are designed by Khiam Chuan Marine Limited (KCM) of Singapore, and are being built at Nanjing Eaststar Shipyard.

ZF Marine’s commercial craft sector was involved in this project at an early stage, working with Vroon, KCM and the shipyard, and offering various propulsion alternatives to suit the vessel design requirements. The finally-agreed propulsion system configuration comprises twin diesel engines each driving CP propellers via reduction gearboxes at the stern; and one electric frequency converter-driven retractable azimuth bow thruster acting as the main propulsion system when the vessel is patrolling close to offshore platforms.

Following collaboration between ZF Padova, ZF Marine Shanghai and ZF Marine Krimpen, ZF was finally approved by Vroon as the propulsion supplier and awarded the order by Nanjing Eaststar shipyard for all six vessels. Each shipset includes two ZF CP KH 515 propellers, two ZF W4610 gearboxes and a ZF AT 4111 RT-FP thruster.

Two of the ERRVs are scheduled for delivery during the last quarter of2012, with the remaining four in 2013. More orders may follow depending on the success of the first six ships.

INDIAN COAST GUARD ORDERS TRANSMISSIONS

ZF Marine Middle East has confirmed ZF transmission systems are being used in the Indian Coast Guard’s latest fleet of 48m 35 knot inshore fast patrol vessels. This is part of the Coast Guard’s expansion programme and follows a contract awarded to India’s Cochin Shipyard, which is building 20 of the triple-engined vessels.

Around 190 ZF 7600 gearbox units coupled to 16V 4000 MTU M90 engines have already been supplied to the Indian Coast Guard and Navy in recent years. This order comprises 60 MTU 16V 4000 M90 engines rated 2,720kW @ 2100rpm with 60 x ZF 7600 2.037:1 transmissions coupled to waterjets.