Multraship's Multratug 32 has an innovative carrousel towing system and in-line Voith Schneider propellers for high manoeuvrability and stability
Novatug's Multratug 32 is the world's first Carrousel Rave tug, which has a rotating towing system combined with Voith Schneider propulsion for 360¡Æ manoeuvring. This 31.9 m tug was designed by Robert Allan in co-operation with Voith and Novatug, built by Damen Shipyards and classed by Bureau Veritas.
Multratug 32 has been leased to Multraship Towage & Salvage and started operations in the Netherlands at the end of January. For Novatug managing director Julian Oggel, its specialised design was influenced by towing safety considerations. ¡°In principle, capsizing is impossible when towing with the carrousel system,¡± he said. ¡°This allows for the safe execution of manoeuvres that would be very high-risk with traditional tugs.¡±
He told Tug Technology & Business that the ports of Rotterdam in the Netherlands and Antwerp, Belgium, had shown interest in the Carrousel Rave tug for manoeuvring ships in tight harbour areas and reducing emissions.
At the heart of this tug is a patented carrousel system, which is a towing winch on a steel ring. Machinefabriek Luyt delivered the carrousel unit, which consists of a base structure surrounded by a ring that can rotate freely 360¡Æ in the horizontal plane around the tug¡¯s deckhouse. This carries a towing winch that can tilt vertically 45¢ª so that the winch can always be aligned with the towing line, providing optimal control.
¡°As a result, we can work with large seagoing vessels at much greater speeds and that means the vessels themselves are easier to steer,¡± said Mr Oggel, adding that ¡°this is a major step forward for both efficiency and safety.¡±
Multratug 32 is propelled by two Voith Schneider propellers arranged in-line, which means the tug can have a slender hull without affecting its stability. These Voith 32RV5 EC/250 propellers were chosen for their precise thrust control, quick response and insensitivity to variations in inflow direction.
They enable the towline force to be continuously controlled safely and precisely via Voith electronic joystick controls in the wheelhouse. These Voith Schneider units are driven by two ABC 12VDZC engines that each deliver 2,650 kW at 1,000 rpm. These systems give Multratug 32 a bollard pull of 77 tonnes.
Damen Shipyard¡¯s Theodor Buschmann yard in Hamburg completed the tug¡¯s structural building work before it was transferred in Q4 2017 to Damen Maaskant in Stellendam, the Netherlands, where it was outfitted and completed. By the end of 2017, Multratug 32 was undergoing towing tests and sea trials and was officially completed and handed over to the owner on 31 January 2018.
Multraship Towage & Salvage managing director Pepijn Nuijten said the Carrousel Rave design improves crew safety and reduces fuel consumption. ¡°The ingenious design effectively uses the kinetic energy from the tow rather than its own engine power,¡± he said. It means the same towing force is achieved at lower levels of fuel use. ¡°The savings amount to at least 25% on an average operation involving a seagoing vessel,¡± he said.
More details will be in the next issue of Tug Technology & Business, that will be published later this month.