Feature 4
to offer optimised payload capacity and in both magnitude and direction. Voith such as anchor-handlers, which are
greater operating efficiency compared to claims that a platform support vessel such subject to extensive periods of high- and
similar-sized vessels, while facilitating as Edda Fram using two 2500kW cycloidal low-load operation. Hybrid powering
simplified construction methods to propellers requires some 10-20% less combines both diesel-mechanical and
reduce unit production costs. power, depending on load conditions and diesel-electric propulsion, facilitating
Diesel-electric is favoured by Rigdon speed, compared to alternatives such as three main operating modes, namely drive
on account of the benefits it offers contra-rotating azimuth thrusters. to the propellers by the diesel engines only,
PSVs in terms of overall fuel efficiency, by the electric motors only, or by the diesel
redundancy and flexibility of installation. Hybrid solutions engines and electric motors together.
The advantages are especially apposite Hybrid propulsion systems are finding
to the typical operating profile of a increased favour in the offshore support AHTS
PSV, which spends much of its time sector, conferring flexibility and efficiency Wärtsilä has developed a new, hybrid
at reduced power, as when holding across the full mission profile of vessels propulsion system for different designs
station off a platform. Each of the 654s
is powered by two 1235kW generators,
driven by Cummins KTA50 diesels, and
by one 410kW generator, incorporating SCD SCHOTTEL Combi Drive
a Cummins KTA19 engine. Larger
Cummins prime movers are employed for
the more potent, three generators in the
A highly efficient
640-series PSVs.
The three gensets in Rigdon’s new
azimuth drive system
class of offshore support ships supply
electrical energy to two Steerprop
azimuthing drives, one Steerprop fixed
• Combination of electric drive system
drive and two bow thrusters. The level with proven mechanical components
of redundancy meets and exceeds DP2 • Utmost manoeuvrability
dynamic positioning standards. Even if
due to 360° steering
two of the three generators were to fail,
• No shaftline required
the third would still be able to provide
• Extremely compact design
power for propulsion.
• Easy to install by the shipyard
The design advantages of diesel-electric
are demonstrated by the fact that the main
engines for the powering and propulsion
system can be fitted at main deck level.
This has allowed the underdeck volume to
be maximised for revenue-earning, while
also reducing the amount of ancillary
installation work, such as the length of
Our product range com-
runs of exhaust piping, relative to more
2 x SCD 2020
prises azimuth propulsion
conventional arrangements.
systems, manoeuvring
Commissioned in 2007, Østensjø
and take-home devices,
and also complete con-
Rederi’s diesel-electric Edda Fram
ventional propulsion
marked a milestone in the evolution
packages rated at up to
of offshore support vessels, both as the
30 MW. Through our
worldwide sales and
first platform supply ship to employ the
service network we offer
Voith Schneider Propeller (VSP) system
economical and reliable
solutions for vessels of all
and as the first commercial recipient of
kinds and sizes. So
Brunvoll Rim Driven Thruster (RDT) we can provide the right
technology. The decision to employ
2 x SCD 2020
thrust for your vessel.
Voith Schneider cycloidal propellers, in
conjunction with a diesel-electric power
Innovators in propulsion technology
and propulsion arrangement, was founded
SCHOTTEL GmbH
on considerations of overall efficiency,
Mainzer Str. 99 · D-56322 Spay/Germany
manoeuvrability, redundancy and safety.
Tel.: +49 (0) 26 28 / 6 10 · Fax: +49 (0) 26 28 / 6 13 00
eMail:
info@schottel.de ·
www.schottel.com
VSP affords stepless control of thrust
Ship & Boat International November/December 2008 39
SSBI_Nov-Dec08_p38+39+40+41+42+44+45+46.indd Sec1:39BI_Nov-Dec08_p38+39+40+41+42+44+45+46.indd Sec1:39 111/17/08 3:48:51 PM1/17/08 3:48:51 PM
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