Claims for new and innovative tug designs are frequent these days, but typically are just variations on an existing theme developed by others. While outwardly “just another Voith Tractor”, the new VectRA 3000 design developed by Robert Allan Ltd exclusively for Sanmar contains many innovative ideas from both the builder and designer aimed at developing a cost-effective VSP tug for the world market.
The design challenge given to Robert Allan Ltd was to create a VSP tug which was under 500 GRT and which would incorporate high-speed engines, electronic controls and be fully MLC 2006 compliant for all crew accommodation. The challenges therefore focussed on the machinery design and the overall layout. As experienced designers of VSP tugs, Robert Allan Ltd had numerous designs from their AVT series available to use as baseline references, but as always each new design is tailored to the specific application and the hull form was developed to reflect the latest lessons learned from extensive CFD modelling of hull performance.
Sanmar shipyard is starting the construction of this new VectRA series of tugs which will be offered as one of the standard deliveries from the yards.
The VectRA 3000 design has the following particulars:
Length Overall – 30.25 metres
Beam, Moulded – 13.00 m.
Depth, Moulded – 5.35 m.
Overall Draft – 6.00 m.
GRT – apprx 490
The propulsion system of the VectRA 3000 is the most unique aspect of the design. Drving the Voith 32-R5 250 units are a pair of Caterpillar 3516C high speed diesels, each rated 2525 kW at 1800 rpm. In lieu of the traditional Voith Turbo coupling, the engines are connected to the drives through a pair of Reintjes model WAF 843 reduction gear/clutches. This reduces the transmission losses, thus increasing the overall propulsion efficiency, and also enables the drives to be de-clutched at idle, significantly reducing fuel burn. The use of high-speed engines significantly reduces the space occupied by drive machinery and of course results in much lower weight, allowing a finer more efficient hull form for the same deadweight. The installed cost is also significnatly reduced as well. The machinery combination will deliver a bollard pull of up to 70 tonnes and will drive the hull at a predicted speed of not less than 12.5 knots.
This tug also incorporates the new electronic Voith Remote Control ™ system. This control is set up to work in a combinator mode whereby both rpm and pitch increase together at a pre-defined “ramp up”. It is believed that this is the first installation of high speed engines with VSP drives in conjunction with the Voith Electronic Control System.
The flush deck layout is relatively conventional for a Voith Tractor, but in compliance with MLC 2006 all accommodation is on the main deck, with two single cabins for officers and two double cabins for crew, each with private en-suite lavatory facilities. The galley and mess area adjacent to a central entry/wetlobby area complete the outfit.
The vessel will be equipped with a DMT Type DMT TW-E250kN frequency-controlled electrical drive double drum towing winch with tension indication. Wire capacity is 700 metres of 54mm steel wire for towing and 240 metres of 58mm synthetic rope for harbour asistance on both drums. The band brake holding load is 150 tonnes. Winch performance is rated at 1st speed: 25 tonnes @ 0 – 9 m/min. The electric power will be delivered by two Caterpillar C 4.4 Generators each delivering 86ekWatt
The tug has a fuel capacity of 120 cu.m. and carries 10 cu.m of potable water.
The VectRA 3000 design will be classed by the American Bureau of Shipping, with the notation *A1, *AMS, Towage Vessel, ABCU, Unrestricted Service, Fi-Fi1, HAB(W8), UWILD
For further information on the VectRA 3000 class tug design, contact Sanmar info@sanmar.com.tr or Robert Allan Ltd. (design@ral.ca) .
