Posts: 1587 Joined: November 22nd, 2011, 4:47 am
Location: Marietta, Georgia - USA
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I saw this article about a tiny functional training tug, and it rather caught my interest, so I thought I might try and do one in SB scale. Not sure if I bit off more ( or less, as the case may be ) than I could chew, but here it is.
Original drawing
Edited Drawing
Taken from an article in "The Motorship" Magazine
Floating training aid for tug operation
At first sight a 7.8m vessel seems ridiculously small to be featured in a magazine concerned with ocean-going vessels. But the BRAtt is a serious craft, with a serious purpose – even though most of us would dearly like one to play with.
BRAtt represents Burchett Robert Allan training tug, the fruit of a cooperation between Burchett Marine, a builder or aluminium boats, and well-known naval architect firm Robert Allen Ltd (RAL), which specialises in escort tug design. The need for such a vessel was driven by a perceived manning crisis in the towing industry, with a great number of mariners due to retire soon, and few new recruits to take their place (we say much the same thing in maritime publishing, but that’s a totally separate issue).
Additionally, today’s larger and more environmentally-sensitive ships require more powerful and more sophisticated tugs, with more sophisticated systems, that need experienced and qualified officers and crew.
Burchett Marine has built up valuable experience with radio-controlled model tugs, to give an insight into the special skills needed to handle such vessels. The collaboration with RAL has resulted in a logical development of this idea – a miniature tug, which can be ‘driven’ from onboard, exactly like a full-size tug, and which behaves exactly like the full-sized version.
RAL’s brief was to produce a design for such a training aid which would be large enough to be realistic and fully safe in all training operations, and to offer ‘real time’ response actions; be powerful enough to perform ‘real’ work like a full-size tug; be fully Class certifiable if required; and be small enough to be transportable.
The resulting small tug is 7.8m long x 4.32m wide, with 1.44m operational draught, built on an aluminium hull which follows the characteristic RAL double chine form. Under the counter of the broad stern the hull tucks in quickly providing good water flow over the twin azimuthing drives located aft like a proper ASD tug. Forward, a relatively deep bow is augmented by a skeg that makes BRAtt behave like a ‘real’ escort tug.
Why create a small vessel rather than train crews on a full-size tug? According to RAL, cost is the main reason. The vessel itself costs far less, and only the potential master need be onboard – no other crew is needed, other than an instructor. This means that the skill-based training process is faster, more intensive and more effective. BRAtt is capable of light harbour towage, so cost recovery is possible by using it in an active role.
One area of particular interest is the flexibility in propulsion systems. Four different systems are proposed: a diesel-driven version with conventional propulsion; a hybrid version, using integrated technologies for low emissions; an all-electric BRAtt; and finally, a fuel-cell driven version.
RAL stresses that BRAtt is an ultra-compact, fully-functional Z-drive tug, with operational ship-handling winch, that is exactly like a large tug, simply scaled down. The diesel version is powered by two Cummins QSB5.9-230 HD engines, rated 168 bkW at 2,600 rpm, driving through ZF 280-1 gearbox with a slip-clutch feature which allows operation at below idling speed. The Z-drives are Olympic model HD3, a simple and rugged unit developed originally for Canadian logging/yarding tugs. The package is designed to develop 3,630 kg bollard pull. The engines are flexibly mounted, and provided with Centa flexible couplings.
BRAtt made its debut at the 2010 ITS Convention in Vancouver.
_________________ "Anybody remotely interesting is mad in some way." - The Seventh Doctor
Last edited by Zephyr on February 7th, 2013, 9:08 pm, edited 3 times in total.
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