Towage and salvage specialist Multraship, through its 100 per cent owned subsidiary Novatug BV, has commissioned the construction of two evolutionary Carrousel Rave Tugs (CRTs) from Damen Shipyards Group. RAVE is short for Robert Allan Voith Escort. These new vessels will provide tug operators with more power, more freedom and more durability, as well as eliminating the risk of capsizing under a tow load. Construction of the CRTs will begin immediately under an agreement between Novatug, with Multraship as its first customer, and Damen subsidiary Van der Velden Barkemeyer GmbH. The hulls of the vessels will be built by German shipyard Theodor Buschmann GmbH in Hamburg, with final outfitting carried out by Damen Maaskant Shipyards in Stellendam, the Netherlands. Delivery of the Bureau Veritas-classed vessels is scheduled for first-quarter 2017. The RAVE design was developed by leading naval architecture consultancy Robert Allan Ltd, in conjunction with Voith GmbH. The CRTs have an overall length of 32 metres, and a bollard pull of minimum 70 tonnes. Propulsion is via two Voith thruster units and two ABC main engines of 2,650 kW operating at 1000 rpm. Free running speed is over 14 knots at 5,300 kW. The Carrousel tug's lower operational costs, speed of action and enhanced control over the tow can provide huge advantages over conventional tugs, for example by widening or even removing tidal and/or weather windows for certain ports. Novatug will offer the Carrousel Rave tugs on the basis of long-term bareboat charters, basically a financial or operational lease construction, which is both customary and proven in other capital-intensive industries such as aviation. Leendert Muller, managing director of Multraship, says, "Safety is always our overriding objective, and that it is why we have opted wholeheartedly to produce the Novatug CRT. This new tug design, for the first time, eliminates what has always been the most significant threat to safety in towing – the risk of capsizing under a tow load. The benefits in terms of efficiency and flexibility, meanwhile, are also enormous". "The involvement of Theodor Buschmann and Maaskant completes the so-called Novatug 'dream team' which, over the years, has benefited greatly from the input of Voith, Robert Allan, ABC and the Luyt Group, working closely together and using all their experience and expertise to produce a design which has been awarded the Dutch Maritime Innovation Award." Meanwhile, Multraship has also agreed a deal with Damen for a new state-of-the-art ASD 3212 tug as part of its planned fleet expansion to keep pace with increasing demand for its specialist services. The Dutch-flag, LR-registered Multratug 31 was built at Damen Song Cam, Vietnam. A sister vessel to Multratugs 19, 29 and 30, it will operate mainly in the Western Scheldt area. It has a maximum bollard pull of 83.2 tonnes and a maximum speed of 15 knots. The 453 gt vessel is powered by two Caterpillar 3516C engines and has two Rolls Royce Azimuth thrusters and a 2,800 mm-diameter controllable pitch propeller. The vessel's deck layout features a hydraulically driven escort double drum winch forward and single drum aft, and a 25 mt deck crane. There are two one-man cabins, four two-man cabins, a mess room and galley. Leendert Muller says, "This new tug is needed, because our workload is still increasing and we are confident this will be the case for several years to come. This is not an industry where you can stand still. If you want to stay at the top, you have to keep investing in new vessels, new equipment, new technology, and good people. That is what Multraship is doing, and will continue to do." The Carrousel towing system is as simple as it is effective, consisting of a relatively straightforward steel construction, basically a freely rotating ring (the actual 'Carrousel') fitted around the superstructure of the tug. It is on this freely rotating ring that the tug's towing point is located, as opposed to a conventional fixed towing point that has been the case for as long as towing has existed. Tugboats fitted with the Carrousel towing system can turn around freely relative to the tow without letting go of the line. When there is force on the line, the shifting towing point also changes the centre of force relative to the tug's centre of gravity. The tug's own hull profile can safely be used for generating braking and/or steering forces, based on the lateral resistance of the hull through the water and given the kinetic energy present in the moving tow and/or the current. A Carrousel tug can brake or steer a moving tow much better, faster, cheaper and from any position forward or aft, than any regular tug relying on installed power for braking or steering. A Carrousel tug simply cannot be capsized by a tow load. For its braking and steering operations, a Carrousel tug needs far less added energy, resulting in significantly reduced fuel consumption and emissions. The cost-saving potential on fuel alone is at least 25 per cent, depending on the operational profile of the tugboat. The fact that a tugboat with the Carrousel towing system depends on its lateral hull resistance more than its engines and propulsion systems in order to generate braking and steering forces also results in significantly less mechanical wear on the propulsion train, with lower annual repair and maintenance costs and a longer economic life for the tug itself.
(Press Release, adapted from Towing Line / Hans van der Ster)
The carrousel system saves lives
Novatug thinks it is simply unacceptable that lives are still lost during towing operations in 2015. And 'more of the same' simply will not work. More powerful engines? More brute force? That won't help. Well, maybe just a bit. Marginally. But on the whole, 'bigger' is definitely not 'better'. Novatug has the solution, and can feel justly proud of the fact. It has been a while, let's be honest about that. And that in itself makes it clear that we are not talking about something new. It's not an innovation; it has been two decades in the making. Novatug uses the mass of the adversary to win. Not by continually nudging it with an inert mass, but by taking control through fast and adept maneuvers.The carrousel construction makes it possible to execute unique maneuvers. Maneuvers which are not part of the age-old tricks of the conventional tugboat trade. Different. Safer. The maneuvers that the carrousel allows, combined with the hull and Voith propulsion, mean that the captain benefits from a greatly enhanced freedom of movement. He literally has more room to maneuver safely. It's not an innovation, it's been there for ages. We have only ever tried to equal and oppose the forces of nature by using increasingly powerful engines. But adding ten per cent of extra engine power definitely does not automatically imply an increased result of ten per cent. Far from it.
The Carrousel towing system
The Carrousel towing system is as simple as it is effective. It consists of a towing point on a straightforward steel ring, freely rotating around the superstructure of the tug. Novatug has taken the initiative to develop a game-changing harbour, terminal and escort tugboat, the Carrousel Rave Tug (CRT), around this innovative and patented Carrousel towing system. With the CRT Novatug entered a whole new era in towing. And this not just by using the Carrousel. By a clever combination of low-drag hull design, versatile Voith propulsion, robust ABC engines and special Luyt winch a tug has been developed that will set new and unprecedented standards in safety, fuel efficiency and pulling power. All this is further enhanced by Novatug's business model featuring worldwide service, fixed maintenance costs and lease options. With the development of the CRT, Novatug wants to thrust the tugboat industry forward by a gigantic leap. It's not just an innovation, it's putting thrust in nature.
Long-term bareboat charter
Novatug will offer the Carrousel Rave Tugs on the basis of long-term (up to 20 years) bare-boat charters, basically a financial lease, which is both customary and proven in other capital-intensive industries like aviation. All operational costs with respect to the CRT, e.g. costs associated with fuel, repairs, maintenance and crew, are borne by the towage operators. Together with its industrial partners, Novatug will offer various maintenance schemes for the tug's propulsion train, Carrousel ring and winch so that Novatug's clients are able to manage beforehand the ownership costs of the tugs down to a highly predictable daily rate reflecting the total operational lifecycle cost – only excluding fuel, other consumables and any possible repair costs. The industrial partners of Novatug are able to provide worldwide service.
Tug MULTRATUG 12 in november 2002 the first to be outfitted with the Carrousel system
An existing tug of Multraship (the MULTRATUG 12) was retrofitted with the Carrousel technology and put into regular harbour tug service with Multraship starting late 2002. Specific tests were also undertaken to measure performance and efficiency. Experience and tests with the prototype proved the enormous potential of the Carrousel technology: The Carrousel raises the dynamic braking and steering forces of the Multratug 12 to some 6 times its capability based on static bollard pull, and all that perfectly safely. In 'Carrousel mode' the Multratug 12 realised considerable fuel savings of some 30% overall, as compared to the Multratug 12 without using the Carrousel and on identical jobs. This is particularly impressive given that the MULTRATUG 12 (1) already has a slender hull and (2) has limited capability in 'normal mode' (static BP of just 20 tons), meaning that these comparisons had to be done on (the same) jobs whereby the 'Carrousel mode' was hardly challenged. The 'Carrousel effect' rises steeply when more performance is required. The tests were validated in the context of various Dutch innovation and cleantech subsidies awarded to the Carrousel towing system by the innovation agency of the Dutch government. These subsidies were for research aimed at cleantech solutions to help save fuel and emissions in general as well as in the maritime industry in particular. Academic institutions involved include TNO and the Delft University of Technology
(from: website Novatug: http://www.novatug.nl/)\r\n
video below: testing the carrousel system in Port Revel\r\n