The second vessel of the pair, to the AVT 36/70 E design by Robert Allan Ltd, is also equipped for heavy duty anchor handling. Both tugs are also equipped for firefighting and oil spill response duties.

Particulars of the AVT 36/70E Class, Voith propelled tugs include 36.65m LOA, a moulded beam of 13.6m, a moulded depth of 4.8m and a minimum draft (overall) of 4.0m. Main Propulsion for the AVT36/70E comprises a pair of MaK 8M25 diesel engines, each rated 2,640 kW at 750 rpm and each driving a Voith model 32R5-265-2 cycloidal propeller in tractor configuration. This combination is predicted to deliver a bollard pull of 70 tons, and provide a free running speed of not less than 13.5 knots. The indirect escort steering force is estimated at 110 tons at 10 knots.

Features of the first tug include a large aft deck to facilitate oil recovery operations, a removable escort towbitt to ensure a clear deck during non-towing activities, and oil dispersant spray capabilities. The second tug will have slightly different stern lines to incorporate a 3m long stern roller and a set of shark jaws.

The design features a full raised forecastle running nearly half the length of the tug to provide a high standard of accommodation and the best possible seakeeping capability for operation in exposed conditions.

The vessel will be outfitted to the highest standards for a crew of up to 14 people. Main deck accommodations include three two person cabins, four one person cabins, a galley, mess, galley stores, workshop, oil lab, locker room/lobby, and deck store. The deckhouse at forecastle deck level includes four one person officer cabins. The wheelhouse is designed for maximum visibility with a single control station providing maximum visibility to both fore and aft deck working areas, with the emphasis on the aft deck. The lower deck includes engineer's stores, and laundry facilities. All cabins are of a generous size, and boast en-suite lavatory facilities. The noise level throughout the crew accommodation is predicted to be in the range of 60 dBA, based on utilizing advanced methods of isolating main propulsion machinery, as well as high grade insulations and floating floor techniques.

The operating range at economical cruising speed is estimated at 3,500 nautical miles (minimum). The electrical plant is comprised of three identical diesel gensets, each with a 380 volt/50 Hz power output of 125kW. Fire-fighting will be to a Fi-Fi 1 Class.

The main towing winch is a waterfall style, double drum type in which the upper drum contains 1,000m of 56mm steel wire rope. The lower drum is a split configuration with a 250m synthetic hawser for escorting, and a 150m synthetic line for harbour towing. The anchor windlass, in a horizontal axis configuration, is fitted with two chain wildcats and two warping heads, which are clutched separately.

Towing flexibility is enhanced by the inclusion of a 70 ton radial arm tow hook, while salvage and general stores/deck operations are aided by inclusion of a 25 ton/metre knuckle boom crane.

Shiphandling fenders at the stern (skeg end) comprise a 900 x 450 cylindrical fender above a row of 450mm 'W' block fenders. A 300 x 300 hollow 'D' fender provides protection at the main and forecastle deck sheer lines, and 'W' block type fendering is used again at the bow.

The first tug is scheduled for delivery in late this year, with the second to follow approximately one year later.