ZF Marine reports the delivery of a transmission system for the "Fakir" ice-class Spanish trawler built by Astilleros Armon, SA. for Freiremar, SA. The single screw, ZF W43100 NR heavy-duty gearbox is for a MaK 6M25 engine of 1,850 kW with a speed of 750 rpm at 2.46 kW/rpm.
The design is a cast iron/welded housing, integrated thrust bearing, integrated multiple disc clutch for main operation with rigid mountings, oil cooler and integrated input driven oil pump for transmission lubrication and clutch actuation. It has a standby pump unit with motor and connection flange.
ZF said the power take offs (PTOs) mounted on the transmission are directly driven by the main propulsion engine and provide an economic solution for the power supply. By putting the PTOs on the main reduction gearbox this facilitates the engine room layout, permits easier and quicker installation and saves engine room space thus freeing up room for more cargo.
The gearbox is a two shaft, single stage reduction gearbox with a hydraulically operated multiple-disc clutch rated for continuous duty. The helical gear teeth are case hardened and accurately ground for long life and smooth running. The gearbox is equipped with anti-friction bearings for all shafts. The integrated thrust bearing is designed to take the maximum propeller thrust astern and ahead. The axial self-aligning roller bearing transfers the propeller thrust via the housing into the ship's foundation. The gearbox is equipped with a emergency get-home device (mechanical blocking of the main clutch). The output shaft has split type seals for easy maintenance.
The mountings are rigid, cast on the lower part of the transmission housing and designed to transfer maximum thrust to the ship's structure.
The lubrication and cooling system uses HD-SAE30/HD-SAE 40 in a wet sump with integrated hydraulic pump, directly connected with the input shaft (if the engine starts running, the pump is also running). The oil cooler is seawater-resistant pipe bundle, offering maximum inlet water temperature of 38°C. The system has a standby pump in case of failure of hydraulic pump (operating pressure below 20 bar).
The gearbox is supplied with the usual alarm sensors and gauges, mounted on the gear and connected to a terminal box on the gear housing.
