NEWS
Tugs Looking for a RAVE
review Canada-based ship designer Robert Allan Ltd has teamed up with Voith Turbo Schneider Propulsion (VSP) to collaborate on a brand new tug concept, dubbed RAVE. Te concept will feature twin VSP drives, situated longitudinally along the hull, fore and aſt. Te set-up is similar to that of the Voith Water Tractor (VWT) concept; however, Robert Allan claims that the new positioning of the propellers has been proven in model tests, and by computational fluid dynamics (CFD) analysis, to retain maximum thrust generation with no loss of output – a problem that previously affected the VWT and most side-by-side drive arrangements.
Russian Ministry of Transport. Shipyard Yantar, which is owned by Arctech’s Russian co-parent company United Shipbuilding Corporation, has already commenced work on the hull, with Arctech contracted to outfit and complete the vessel, for delivery in December 2013. Te vessel’s design is to be based on Aker Arctic’s
ARC 100 concept, and she will be mainly specialising in oil spill recovery operations. Measuring 76.4m in length and 20.5m in breadth, she is being built to an oblique design with asymmetric hull and three azimuthing propellers, giving her the freedom to move ahead, astern and sideways. Subsequently, she will boast the ability to proceed on
a continuous mode, ahead and astern, in conditions of 1m ice thickness. In sideways mode, she will be able to generate a 50m wide channel in up to 0.6m level ice. Tree main diesel generator sets will grant the vessel a combined power output of 9MW, with some 7MW dedicated to propulsion power. As well as engaging in icebreaking and oil recovery
work, the ship will also partake in sea towing of other vessels and floating offshore facilities. Mikko Niini, Aker Arctic managing director, said: “Oil combat in ice conditions is one of the major challenges for the international oil industry. After many years of development work, the oblique icebreaker concept represents a new approach for a solution.”
Classification The RAVE tug concept, undergoing model tests. According to the designer, the RAVE tug propulsion
arrangement will also grant operators greater control when navigating narrow waterways, and enable them to operate alongside the assisted vessel in transit. By locating one drive just behind the skeg, Robert Allan expects a greater steering force to be generated. Te group claimed: “Model tests of a similar skeg-drive arrangement show that maximum generated steering force is at least 50% higher than when generated by a single skeg of the same area.” A RAVE tug sized around 24-26m in length will enjoy 40-50tonnes of bollard pull (BP), set to increase to 60-70tonnes BP for vessels sized 29-32m loa, or 90tonnes for a model sized 34-38m loa.
Contract New Arctech order 8
for Russia Arctech Helsinki Shipyard, Finland, working in collaboration with Shipyard Yantar, has been awarded a €76 million (US$92 million) contract to build a multipurpose emergency and rescue vessel for the
ABS: ‘Stop dabbling in design’
Class societies need to back away from the blueprints and stop promoting in-house, energy-optimised designs to their maritime clients, according to ABS president and CEO Christopher J. Wiernicki. Speaking in Houston recently, Wiernicki slammed
what he views as the risk of crossing the line between design and certification. “Since the objectives of the designer and the class society are so fundamentally different, having class societies promote themselves as designers is dangerous,” he remarked. “It destroys the credibility of class as an independent third party, it has the potential to lead to poor designs that could impact the credibility of the whole industry and it upsets the essential checks and balances between commercial pressures and effective safety and environmental risk management. “If ABS were to promote an in-house design for
an energy-efficient tanker, how could we retain our integrity if we were then to approve that same design for construction? I will go even further and say that class societies should not, and cannot, be allowed to, because wearing both [class and designer] hats undermines the basic safety integrity of our entire industry.” He added,
Ship & Boat International January/February 2012
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