Specially designed reduction gears are needed for vessels that use electric motors to augment power from diesel engines to drive thrusters
Manufacturers of transmission systems are developing new clutches and gearboxes to meet the requirements of ship operators choosing hybrid propulsion systems for their new vessels. All major engine manufacturers have developed diesel-electric engines and are introducing shaft generators into their propulsion packages.
More vessels are being powered via a combination of batteries, electric motors and diesel engines, with combined power feeding thrusters. These can be passenger ships, tugs, workboats, offshore support vessels and increasingly, merchant ships.
Katsa has extended its range to accommodate hybrid propulsion applications, adding power-take-off (PTO) gearboxes and clutches and hybrid gearboxes, among other solutions.
“We are providing innovative technical products in demanding applications with our new hybrid gearbox,” said Katsa director of gearbox business Tomi Dewes. The unit combines input from a diesel engine and electric motor to provide power to thrusters.
Katsa’s newest product is a hybrid PTO gearbox, combining diesel and electric motors into a vessel´s propulsion driveline. It is flexible, with an adjustable optimal electric-motor ratio via clutches and control systems.
This hybrid PTO gearbox can cater for engine power up to 1,300 kW and has a hydraulic clutch dynamic torque up to 16,000 Nm. It has independent oil circulation with pump and integrated oil sump, hydraulic clutch control system with proportional valves and a clutch protection system with a remote bridge control. These PTO gearboxes also have flexible gear ratios for optimal engine and pump revolutions.
The range will continue to expand, said Mr Dewes; a version that could provide 2.5 MW of power to thrusters is due to be tested and Katsa also plans to introduce a smaller version of the hybrid PTO in Q4 2020.
Other applications of the Katsa PTO gearboxes and clutches include hydraulic pumps on fishing vessels, tugboats and workboats. These PTO gearboxes can be used for driving and engaging cargo pumps on commercial vessels or mud pumps in oil and gas applications.
Katsa is also developing new winch gears and winch electric powerpacks, incorporating permanent magnet (PM) motor technology. For the marine and offshore sector, these could be used for demanding applications such as escort winches on tugs.
In the Netherlands, Katsa has worked with ADS van Stigt in developing these technologies, including clutched pump-drives, thruster PTO clutches and vessel drivetrain dropboxes.
Reintjes has also developed an electrically driven hybrid solution for gearboxes which enable vessels to sail at slow speeds, below the main engine idle speed. The electric drive is designed to achieve smooth running, with less noise and low energy consumption. For easy installation, the combined electric motor and generator are already flanged to the gearbox. The complete system is supplied with a frequency converter.
Reintjes gears have been supplied to several inland waterway tugs in the US this year. Reintjes WAF 665 reverse reduction gear systems have been installed on a series of towboats built at John Bludworth Shipyard. These are 25.6-m long vessels with Cummins QSK38 main engines that are compliant with Environmental Protection Agency (EPA) Tier 3 emissions requirements. The system turns four-blade Sound Propeller Services stainless steel propellers through WAF 665 gears with internal shaft brakes supplied by Karl Senner.
This newbuilding campaign was completed in May with delivery of Signet Volunteer, Signet Freedom and Signet Puritan to Signet Maritime. These were sister tugs to Ouizee, Raymond Butler and G. Brooks Sperry, which were delivered to leasing group Maritime Partners.
More sets of Reintjes WAF 665 reduction gears were also installed on towboats built at C&C Marine and Repair’s shipyard in Belle Chasse, Louisiana, in 2020. Maritime Partners took delivery of the first of this series of towboats, Paula M. Sperry, and leased it to Centerline Logistics. This 25.6-m long vessel has two Cummins QSK38-M1 main engines paired with two Reintjes reduction gears. Reintjes WAF 665 reduction gears have a power range from 700 to 1,400 kW.
Promac has supplied gearboxes to the tug newbuildings taking place at Damen Shipyards group. These are combined with Caterpillar main engines that drive Kongsberg US series thrusters.
Promac has also developed ram-type steering gears for small spaces. It has designed gear systems to drive electro-hydraulic pump units and PTO-driven hydraulic pumps. Promac supplies step-up front-end gearboxes with various ratios, torques and multi-shaft executions, with horizontal and vertical shaft offsets. It also supplies gearbox systems with an integrated fire-fighting pump, hydraulic clutch unit and right-angle gearbox units for all types of thrusters.
Geislinger has equipped fast ferries in the US with a lightweight shaftline system. These carbon-fibre shafts reduce bearing loads on other propulsion equipment.
The shaftlines are maintenance-free and include carbon-fibre machinery and components, such as composite shaftline flanges. This results in weight savings of 50% in comparison to shaftlines with steel flanges, said Geislinger.
For systems with high dynamic misalignment, Geislinger provides shafting systems with composite misalignment couplings that allow for axial, radial, and angular movement during operation.
These shafting systems have been installed by Nichols Brothers Boat Builders on two fast ferries it is constructing at its shipyard in Freeland, Washington state, to a BMT design. Geislinger is also supplying carbon-fibre shafts and Gesilco misalignment couplings to a fast ferry being completed by Mavrik Marine.
Naval ship gears
RENK has supplied power plant and gear systems to naval ships being built in Turkey, Spain and Pakistan. It is supplying power systems to four Ada-class, Milgem corvettes being built for defence forces in Turkey and in Karachi Shipyard, Pakistan. The first two of these ships are scheduled to enter service in 2023 and the other two in 2024.
They will have a RENK Codag cross-connect propulsion plant, consisting of a gas turbine rated at 23,000 kW and two diesel engines, each rated at 4,320 kW, which drives a controllable pitch propeller via a two-speed main reduction gear.
In Spain, Navantia has built corvettes with MTU propulsion engines and diesel generators, and RENK gearboxes. The first of these, Al-Jubail, was launched earlier this year, while a second, to be named Al-Duriyah, is scheduled to be launched in Q4 2020.
New chief executive and Australian expansion
Siemens subsidiary Flender Group has appointed a new chief executive and flagged up expansion plans in Australia. Andreas Evertz has succeeded Stefan Tenbrock who retired from the chief executive position on 1 June 2020. Mr Tenbrock had worked for Flender for 36 years and had been chief executive since 2015.
Later this year, Flender will open a purpose-built facility in Bayswater, Western Australia, to supply gearboxes. The 3,500 m2 facility is due for completion in September. It will have a 1.5 MW test bench capable of testing complete drive systems up to 6.6 kV.