VESSEL REVIEW | WS Rosalvo – New Brazilian escort tug boasts low-emission features

Brazilian towage company Wilson Sons has expanded its fleet of escort tugs with the completion of a new vessel by its own shipbuilding arm in Guaruja in Sao Paulo state.

The RSD tug WS Rosalvo utilises a design originally developed by Netherlands-based the Damen Shipyards Group. The newbuild measures 24 by 13 metres and is powered by two box- and keel-cooled Caterpillar 3516 2,525kW diesel engines that drive Kongsberg Maritime azimuthing thrusters housing 3,000mm fixed-pitch propellers.

The propulsion system delivers a bollard pull of 90 tonnes and a speed of 11 knots. The engines are fitted with an exhaust gas aftertreatment system, making WS Rosalvo one of the first Brazilian-owned tugs that comply with IMO Tier III NOx emissions regulations even before these come into force in the country. According to Wilson Sons, the tug generates 75 per cent fewer NOx particles compared to conventionally-powered counterparts while the twin fins incorporated into the hull ensure a hydrodynamic design that reduces fuel consumption over the same sailing distances by around 14 per cent, thus lowering CO2 emissions.

The vessel's layout emphasises safety. The exterior deck has no obstructions due to the escort winch being installed flush within the deck to minimise corrosion and water buildup. The wheelhouse windows are made of high impact-resistant safety glass but are large enough to ensure there are no blind spots. The mast is foldable for ease of maintenance.

The tug is also capable of firefighting thanks to the installation of a Fifi1 pump with a flow rate of 2,400 cubic metres per hour.

WS Rosalvo is homeported in Rio de Janeiro but will be operated mainly out of the Port of Açu alongside seven other tugs in the Wilson Sons fleet.

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