Environmental Engineering Reference
In-Depth Information
Large propellers are usually used in very large container ships, bulk carriers and
tankers as a controllable pitch propeller [
30
].
8.4.2.2 Carbon Fiber Propellers
Carbon fiber propellers consist of elastic carbon fiber composite material which
effectively protects against cavitation. They can be used in many types of ships of
all sizes. Carbon fiber propellers can be adapted to different loads with a wide
range of special contours and profiles. The result is higher propeller efficiency,
light weight, less vibration and less noise [
31
].
8.4.2.3 Pod Propulsion Systems
Pod propulsion systems are directly driven by an electric engine system. An
efficient synchronous or asynchronous motor is built below the stern in a gondola
which swivels all around. This ''rotating'' gondola is widely used in ice breakers,
cruise ships and other large ships with a high maneuvering ability. The main thrust
propeller is placed in front of the system and the auxiliary propellers are behind
them [
32
,
33
].
8.4.2.4 Linear Jets
The linear jet is a relatively new ship propulsion system which is a highly powerful
technology and has a large thrust load. In addition, the noise of the propulsion is
reduced. It consists of a nozzle system without a ring around the propeller. On the
one side, linear jets are advantageous for high speeds of up to about 35 kn
(64.8 km h
-1
). On the other side, the fuel efficiency is relatively low because of
high internal resistances in the system [
34
].
Combinations
with
the
Voith-Schneider
propeller
technology
are
modern
development directions [
35
].
8.4.2.5 Ring Propeller Driving and Maneuvering Systems
Ring propellers are driving and maneuvering systems which are directly driven by
an electric motor. They usually operate as a common generator and an engine with
very large diameter, and are used to provide extremely high power, low speeds,
and high gear torque. The advantage of the large stator and rotor diameter is the
optimal maneuvering ability. The construction is mounted in a central position to
safely absorb high radial and axial forces (see Table
8.2
)[
36
].
Search WWH ::
Custom Search