Reintjes’ biggest yet serves Canadian container ship

The largest reduction gearset ever produced by Reintjes entered service in April as part of the propulsion plant of the feeder container ship Oceanex Avalon, built by the JJ Sietas yard in Germany for Montreal-based owner Oceanex. The 56-tonne unit measures 4.1m long x 3.4m wide x 4.2m high.

Reintjes’ SVA/SVAL series gearboxes have been in service since 1984, the modular concept continually refined and adapted by the German company over the years to meet customer requirements. The SVAL 1250 type built by the Hamelin factory for the Oceanex project was designed to transmit the 11.12MW output from the eight-cylinder MAN B&W 58/64 medium speed main engine to the propeller shaft via a clutch.

An engine speed of 428 rpm is reduced to 119 rpm for the CP propeller, the reduction ratio of 3.583:1 selected to secure optimum propulsion for the application. Designed in accordance with Germanischer Lloyd’s ice class E3 requirements, the gearbox features a special steel housing to absorb the additional dynamic stresses in icegoing conditions.

A combined power take-off (PTO)/power take-home (PTH) facility is incorporated to allow economical electrical power generation and provide an emergency propulsion mode. The PTO drives a 2,000kW alternator via its own clutch, and the PTH (also with a separate clutch) connects a 2,100kW electric motor to the shaftline via the gearbox, enabling propulsion to be maintained even with the main engine out of action.

The higher oil requirement resulting from the special size of the three hydraulic clutches is met by an innovative electric dual-pump system with two circuits.

This division into working pressure and lube oil pressure considerably reduces the power loss of the gearbox, Reintjes explains, as the entire 650 litres/minute do not have to be brought to and maintained at working pressure. A significant reduction in the power consumption of the pumps further benefits the ship’s network.

Reintjes’ numerous references in the fast ferry transmissions sector were extended last year by an order from Austal Ships for four VLJ 6831 K71 HL/HR sets. The gearboxes were required to serve the power trains of an 810-passenger/154-car catamaran booked by Hellenic Seaways (formerly Hellas Flying Dolphins) of Greece.

During the commissioning of Highspeed 5 at the Australian yard earlier this year Reintjes specialists took the opportunity to acquire basic measurement data for subsequent condition monitoring in service.

Condition monitoring involves recording vibration signals from the tooth meshing, roller bearings and shaftlines located forward and aft of the gearbox and then evaluating the data with an advanced analysis method. Operating conditions are also noted and oil samples taken for the assessment.

Such regular CM analyses, says Reintjes, underwrite cost savings through ‘maintenance on demand’ and also allow assessments of the drivetrain status following, for example, foreign bodies lodging in waterjets or nets tangling in propellers. Planned and prompt maintenance can significantly reduce downtimes and repair costs.

• Reintjes recently enhanced its training facilities for in-house

service staff and those of subsidiaries and agencies as well as customers’ operating and maintenance personnel. A new centre at Hamelin provides training in gearbox technology and servicing, dismantling and assembly of clutches, setting bearing combinations, replacing heat exchangers and valves, fault analysis, and complete repairs and overhauls

Choice of drives for double-ender

A large double-ended diesel-mechanical ferry delivered in March to the Norwegian operator Basto Fosen is distinguished by innovative Wartsila transmission systems linking the main engines and propellers. Basto III was commissioned from Poland’s Remontowa yard for service across the Oslo Fjord between Moss and Horten.

Diesel-electric propulsion with steerable thrusters is commonly adopted for such vessels but a diesel-mechanical/CP propeller solution in this application promised a 10 per cent cheaper installation and higher fuel economy. Fuel consumption at a service speed of 14 knots is reportedly around 20 per cent more with a diesel-electric/steerable thruster system, resulting from electrical losses, higher ship resistance and lower efficiency of the thrusters.

A complete propulsion package from Wärtsilä group suppliers embraces two 6-cylinder R32LN engines, each developing 2,460kW at 750 rpm and arranged to drive feathering CP propellers at bow and stern via gearing and clutches. The 3.4m-diameter Lips CPS100 propellers are four bladed, highly skewed stainless steel designs.

Either propeller can be driven by either or both engines, a cross-over shaft connecting the aft engineroom machinery with the forward engineroom machinery.

Each Wärtsilä TCH125H50V57 reduction gearbox is equipped with three hydraulically-operated multi-disc clutches – a propeller clutch, an engine clutch and a cross-over clutch – facilitating these operating modes:

• forward engine driving the forward, aft or both propellers

• aft engine driving the forward, aft or both propellers

• both engines driving the forward, aft or both propellers at the same time.

Each gearset is designed to absorb 2 x 2,460kW at 750 rpm and yield a single output of 4,920kW at the propeller speed of 192 rpm.

The degree of redundancy – enhanced by the separate enginerooms and watertight bulkheads between gearboxes and sterntubes – earned the ferry a DNV classification which includes its highest redundancy notation: ‘RPS’ signifies that at least 50 per cent of propulsive power can be restored after any single failure in the propulsion train.

New composite membrane shaft system from Centa

Centa has further developed its Centadisc-C composite membrane shafting system for marine drives, which was introduced around two years ago for torque applications between 2kNm and 20kNm. Manufactured from high tensile fibre-reinforced plastics, this G-series allows angular misalignments of 2-degrees transient and 1.3-degrees permanent for each membrane set.

A new F-series has identical connecting dimensions to the original series but higher misalignment capabilities, exploiting a tough high tensile plastic material without fibres. The transmitted torque capacity is slightly reduced but the allowable angular misalignment can be significantly increased to as much as 4-degrees transient and 2.64-degrees permanent for each membrane set.

Centadisc-C membranes are normally connected in pairs to each end of the intermediate tube to form a homokinetic, double cardanic system. The intermediate tube is usually made of either glassfibre- or carbon fibre-reinforced composite material, with the connecting flanges of steel, stainless steel or aluminium and adapted to the application.

Low weight and corrosion resistance are cited by Centa for the system, which can reportedly absorb any kind of displacement or misalignment and facilitates long spans without intermediate bearings.

Geislinger couplings smooth Algerian ferry drives

A pair of twin-screw ropax ferries which joined the fleet of Algerian operator ENTMV in 2004/2005 are propelled by two Wärtsilä 12V46 medium speed engines, each driving a Wärtsilä CP propeller via a Wartsila reduction gearset and Geislinger couplings.

With capacity for 1,300 passengers, 300 cars and 42 trailers, the 33,333gt BV-classed Tassili II and El Djazair were built by IZAR’s Sevilla yard for Mediterranean service between Algiers, Alicante and Marseilles. Each main engine develops 12.6MW at 500 rpm to give a service speed of 22 knots, the output speed reduced for the associated shaftline and Wärtsilä CPS 115 propeller by a Wärtsilä SH115 gearbox.

Noise and vibration are reduced by the Geislinger couplings (type BC 110/25/106N/2/R + GFL S90T6A) – combinations of the Austrian company’s elastic damping and FlexLink designs – which handle torsional vibrations and high misalignments between engines and gearbox/shafting. MP