Wind – a jack-up barge for servicing
wind turbines at sea
S
ervicing wind turbines at sea often
too high, resulting in a
takes place in very demanding condi-
looser grip on the water.
tions. This sets high requirements for the
Per Kristensen, Marine
service vessels. DBB Jack-Up Services A/S
Superintendent at DBB says:
owns a self-propelled heavy-lift barge –
“The energy consumed by pro-
appropriately named Wind − which is ca-
pulsion on the Wind has fallen from
pable of replacing heavy components at a
approximately 1,100 kW to 800 kW at
height of up to 100 metres.
nominal speed. I am surprised that the
DBB Jack-Up Services A/S, based in
energy savings have been that high com-
Aarhus, Denmark, was established in 2008
pared to our previous diesel engine driv-
as a sister company to Dansk Bjergning og
en solution.”
Bugsering A/S (DBB – Danish Salvage and
The torque of the thrusters is moni-
Towing Company Ltd.), primarily to pro-
tored closely by the Vacon AC drives to en-
vide first class services and equipment to
sure that the thrusters are only operated
the offshore wind industry, with a focus
within the permitted torque range. This
on maintenance.
In 2010, DBB Jack-Up Services A/S
contacted Liebherr and asked them to
mount an LTR 11200 crane on its self-propelled jack-up barge Wind. It took just one
week for the crane to be installed on the
barge at the Orskov shipyard in Frederikshavn, Denmark. The Wind is the first ship
to have a permanently mounted telescopic crane of that size on board. DBB JackUp Services A/S chose Vacon low harmonic
air-cooled AC drives to control the vessel’s
propulsion and the operation of the crane.
DYNAMIC CONTROL BRINGS
ENERGY SAVINGS
In contrast to conventional propulsion with
is essential when changing the direction
a diesel engine, the speed of the thrusters
of the azimuth thruster unit, for example,
used in Wind’s propulsion is dynamically
since this cannot accept full torque if it is
controlled by Vacon AC drives. This brings
at an angle to the direction in which the
energy savings. The thruster speed can be
vessel is sailing.
optimised to the actual speed of the ves-
Vacon’s scope of delivery [