Z-drive

This article is about the marine propulsion unit. For the common network drive letter, see file server.

A Z-drive is a type of marine propulsion unit. Specifically, it is an azimuth thruster. The pod can rotate 360 degrees allowing for rapid changes in thrust direction and thus vessel direction. This eliminates the need for a conventional rudder.

The Z-drive is so named because of the appearance (in cross section) of the mechanical driveshaft or transmission configuration used to connect the mechanically-supplied driving energy to the Z-Drive azimuth thruster device. This form of power transmission is called a Z-drive because the rotary motion has to make two right angle turns, thus resembling the letter "Z". This name is used to differentiate the arrangement of drive to that of the L-drive. The Z-drive is unique in that it uses a mechanical device to drive the propellers rather than via electrical motor.

Origins

The Z-drive transmission was used in the first azimuth thrusters built by Hollming in Finland in the 1960s under the Aquamaster brand name.^[1]. The Aquamaster Brand was then acquired by FinnYards.^[2] The device is different to the Voith-Schneider marine propulsion system (also mechanically linked), which can also quickly change the direction of thrust, as the Z-drive uses a shrouded conventional screw which pivots or roatates or propeller rather than the variable geometry blades of the Voith-Schneider.

Innovations

Aquamaster brand was bought out by FinnYards, which later sold to Ulstein Group. Veth Motoren BV has innovated its' in-house designed Z-drive system- the most noteworthy a fully retractable version- which can be fully retracted into the ship's hull.^[3]

Types

• Counter-rotated
• Integrally installed/hull installation
• Deck mounted outboard
• Retractable

Applications

• Floating dredges
• Tank ship
• Coastal trading vessel (coasters)
• Platform supply vessel
• Passenger ship
• Ferry
• Trawler and Fishing trawler
• Cargo ship
• Self-sailing pontoons
• Barge
• Yacht
• Tugs

See also

• Azipod
• Propulsor

Notes

• US Military evaluation of control systems: [1] (download-able PowerPoint Presentation)
• Pleuger L- and Z-drive