Tarbit Shipping is a Sweden-based
company that has been transporting bitumen,
petroleum products and chemicals since
1962. The company currently operates three
ships under the Swedish flag and another 10
under the Dutch flag through Tarbit Tankers
BV. The company prides itself on its high level
of environmental safety, and this conversion
project is in line with their philosophy.
LNG reduces emissions and costs
This is the first marine installation in the world
to convert Wärtsilä 46 engines to Wärtsilä
50DF engines, and the first 50DF marine
installation with mechanical propulsion.
Wärtsilä has a unique expertise and
experience with dual fuel technology, as well
as with fuel conversion projects, which is why
we chose them for this turnkey project, says
Anders Hermansson.
The scope of the conversion package from
Wärtsilä included deck-mounted gas fuel
systems, piping, two six-cylinder Wärtsilä 46
engines converted to Wärtsilä 50DF units with
related control systems, and all adjustments
to the ship’s systems necessitated by the
conversion. The engines are connected
directly to the propeller shafts through a
reduction gearbox. This enables a significant
improvement in propulsion efficiency, reduced
fuel consumption, and corresponding
reductions in emissions, meaning lower
carbon oxide emissions, and virtually
no sulphur oxides or particle emissions
whatsoever. This is also the first LNG fuelled
vessel to be classified by Germanischer Lloyd.
Smooth project progress
The practical work with the fuel conversion
of the ‘Bit Viking’ started in August and was
finalised in October 2011 when the vessel was
handed over to the customer, Tarbit Shipping.
– As this was the first time that such
a conversion was made on a marine
installation, I must say that everything went
very smoothly, except for some minor issues
that could be expected of this kind of project.
I am very satisfied with the technological
efficiency of the Wärtsilä solutions and the
expert way in which this conversion project
has been handled. They know what they are
doing, says Hermansson.
Safe and convenient LNG onboard
storage
The ‘Bit Viking’ utilises Wärtsilä’s new LNGPac
system, which enables the safe and convenient
onboard storage of LNG. The two 500 cubic
metre LNG storage tanks are mounted on
deck to facilitate bunkering operations. The
storage tanks provide the vessel with 12 days
of autonomous operation at 80% load, with
the option to switch to marine gas oil if an
extended range is required. When visiting EU
ports, which have a 0.1% limit on sulphur
emissions, the vessel operates on gas.
Excellent performance
The ‘Bit Viking’ is time chartered by Statoil
– the Norwegian state-owned oil and gas
company – and operates along the Norwegian
coastline. Since the re-commissioning, the
vessel has been running solely on gas and
there have been no problems with either the
converted engines or the LNG equipment.
– Actually, the vessel has performed even
better than expected, says a satisfied Anders
Hermansson.
By carrying out this large-scale
conversion project, and equipping the vessel
with the new Wärtsilä LNGPac system, the
ship’s emissions have been significantly
reduced. This is obviously of tremendous
benefit not only to the environment, but also
to the engine room environment, since it is
now much cleaner when there is no heavy
fuel oil in use. All in all, this successful
LNG conversion strengthens our customer
relations even further, concludes Anders
Hermansson of Tarbit Shipping.