Voith Linear Jet Propulsor
Voith, Germany, has introduced a new ship propulsor called the Voith Linear Jet, designed for vessels with a mixed usage profile operating in the 30 to 40 kn speed range. Typically Navy and Coastguard vessels and motor yachts fall into this category as well as certain ferry types where speeds of around 30 kn are commonplace for cruising or patrolling, yet there is a requirement to sprint at speeds of 40 kn or slightly above.
Caption: The first application of a Voith Linear Jet , a twin installation in a
62 ft (19m) catamaran Windfarm Servicing Vessel designed by BMT-Nigel Gee Ltd
Image credit: BMT-Nigel Gee Ltd
Until now the propulsion options for this type of application use a high speed or medium speed diesel engine to power a high speed propeller with conventional P bracket drive or a water jet, both alternatives can compromise slow speed performance with an associated lowering of efficiency.
The Voith Linear Jet is a specially ducted propeller with aft mounted stator and according to Voith, it removes some of the disadvantages of a waterjet without sacrificing top speed and acceleration. The installation is straightforward; through life cost benefits include a lower sensitivity for marine growth and lower maintenance and high reliability.
To simplify the task of predicting the performance of a vessel using the Voith Linear Jet and in particular giving a guarantee on vital issues such as top speed, onset of cavitation, Voith has developed a powerful tool for the Naval Architect called the Numerical Towing Tank. For any specific project the tool generates a full report on operating conditions and performance analysis with the aim of optimising the installation and ensuring the success for every project.