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Marine Propulsion & Auxiliary Machinery

Marine Propulsion & Auxiliary Machinery

Electrical gearboxes and brakes revealed for environmental tug operations

Mon 02 Apr 2018 by Martyn Wingrove

Electrical gearboxes and brakes revealed for environmental tug operations
Dellner Brakes has developed an electrical-powered STL with a stopping torque of up to 285 kNm

Katsa is preparing to introduce a hybrid power take-off gearbox this year and Dellner Brakes has unveiled an electrical stop, turn and locking system for workboats, including tugboats

Katsa is developing a hybrid power take-off (PTO) gearbox that can be installed on workboats, tugboats, offshore support and fishing vessels that have electric and diesel propulsion and auxiliary machinery.

These hybrid PTO gearboxes are expected to be introduced to Katsa’s existing range at the SMM exhibition in Hamburg, Germany, in September. Their design is based on the company’s existing PTO gearboxes and has been adapted to fit on to diesel-driven and electric motors in a vessel’s propulsion driveline.

Katsa sales manager Mikko Happonen said these hybrid PTO gearboxes will have “wide flexibility for adjusting the electric motor ratio, utilising different clutches and control systems.” These adjustments will be similar to the flexibility that the existing Katsa range already has for propulsion and machinery on workboats, offshore support and fishing vessels and tugboats.

Its gearboxes are tailored to suit each specific combination of vessel and owner requirements, he said, with typical tasks such as generating hydraulic power supplies for machinery on various types of workboats. These PTO gearboxes can also be used for driving and engaging cargo pumps on commercial vessels or mud pumps in oil and gas applications, said Mr Happonen. Since September 2016, these gearboxes can also be used for marine fire-fighting, including on FiFi classed vessels.

These gearboxes are designed to manage power of up to 1,200 kW and clutch torques to a maximum of 16,000 Nm, depending on the application and gearbox/clutch configurations, Mr Happonen explained to Tug Technology & Business. Gear ratios can be adapted to suit what the project requires.

Katsa has also developed an integrated control system that helps vessel operators extend the lifetime and performance of the gearboxes and clutches. “The control system can be either integrated into the main control or act separately as a stand-alone unit with a panel on the vessel’s bridge,” said Mr Happonen.

Its existing PTO gearboxes and clutches have water coolers and independent oil circulation with pumps that have integrated oil sumps. The hydraulic block has an integrated oil filter that was designed for marine applications. Optional additions to the gearbox include integrated controls and clutch protection, these will also be available for the hybrid PTO range when that is introduced in September.

Electric-powered braking

Dellner Brakes has developed an electrically powered stopping, turning, locking (STL) system that fits around a vessel’s propeller shaft. These modular units are suited to hybrid and mechanical propulsion and can be operated remotely from an electronic push button panel in a control room or by a handheld remote control or from a mobile device if there is wifi on board.

These STLs include an electrical disc brake that quickly stops the shaft in any position. After the brake has stopped the disc, an electric gear wheel turns the disc and connected shaft at a variable speed into an exact position for locking, explained Dellner Brakes chief executive Marcus Aberg. Once in position, the locking mechanism pushes a tapered pin into a machined slot on the brake disc. “This locks and holds the shaft securely in place, even in ship failure modes,” he said.

Vessel operators can choose one, two or all three of the stopping, turning and locking functions. “Our all-electric STL is the first of its kind in the world and has a patent pending,” said Mr Aberg. “It is fully automated so the operator can instigate the entire stopping, turning and locking procedure with a single press of a button,” he explained to Tug Technology & Business. There would be no need for manual intervention.

Dellner’s standard range has a stopping torque of up to 285 kNm, turning torque up to 119 kNm and locking torque up to 600 kNm. Electric STLs can also be adapted for higher torques where requested.

“Our system enables faster directional changes with maximum manoeuvrability,” said Mr Aberg. This is useful for quickly stopping the propeller when alternating from forward to reverse or locking the shaft to avoid drag, especially in narrow or shallow water.

It can be applied to twin propeller or multiple screw vessels as it can be used to stop, hold and lock one of the shafts while the others are operating at reduced speed, or at full speed for safe return to port. Mr Aberg added that an STL can also hold a broken shaft or propeller in place while others are operating.

“Shaft rotation can exercise water-lubricated bearings and help reduce marine growth on the propeller blades”

There are machinery safety applications, too. For example, an STL can secure a propeller if the vessel is drifting or is buffeted by waves, preventing damage to the shaft and bearings. When in harbour, it can rotate the shaft through 180˚ to stop the shaft from bending. “Shaft rotation can also exercise water-lubricated bearings and help reduce marine growth on the propeller blades, all without needing to turn on the engines,” said Mr Aberg.

“The turning and locking functions make routine maintenance and blade assembly quicker, easier and safer.” STLs can also be used for turning the shaft and propeller for inspection and lock it securely for maintenance.

Mr Aberg said an electrical STL requires less downtime and there is “no need for oil changes or expensive pressure testing.” He said it is applicable to small- to medium-sized vessels including tugs, ferries and offshore support vessels. “Being electrically-powered, it helps lower fuel consumption and reduces load on propulsion systems and offers considerable safety benefits,” he said.

Crowley extends Wärtsilä engine maintenance agreement

Wärtsilä has secured an extension to an agreement it has with Crowley Maritime Services to maintain tugboat engines. The original agreement was due to finish in 2019 but it has been extended to 2023.

This agreement covers maintenance and technical response for 22 Wärtsilä engines that are installed on 11 articulated tug barge (ATB) units that operate in the US. It also includes technical services, troubleshooting and performance guarantees in terms of response time when unforeseen technical issues occur.

Wärtsilä will have a dedicated support team for addressing problems as they arise and regular maintenance to maximise the uptime of these vessels. It said this was Wärtsilä’s first maintenance agreement to cover complete propulsion systems, including seals and bearings.

Flap rudders retrofitted to 1970s-built towboats

Becker Marine Systems has secured orders for its flap rudders for retrofitting on US towboats. New Orleans, Louisiana, headquartered vessel owner Canal Barge Co has been installing Becker flap rudders on towing vessels built in the 1970s to improve fuel efficiency and manoeuvrability.

So far, two 1975-built vessels – Susan L Stall and Eugenie P Jones have been retrofitted with these flap rudders. Another set is on order for installation on Merrick Jones in Q1 2019.

Becker flap rudders lower fuel consumption during long hauls in inland waterways. Canal Barge towboats operate throughout the Mississippi River during long-haul cargo transportation.

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