The identical sister-ships have an overall length of 26m and a beam of 10.8. Two Caterpillar 3512B main engines, each rated 1,305kW at 1,600rpm, drive Rolls Royce US205 propulsion units to deliver a continuous bollard pull of 40 tonnes, and provide a free running speed in excess of 12.8 knots.

Deck machinery has been designed to enable the tugs to connect bow first to the transoms of the barge for pushing in sheltered waters, without need for a barge notch or a patented coupler system. This arrangement includes a pair of manual barge connector winches on the fore deck, and a double-drum winch aft. The latter tensions the two primary connector cables around a pair of large diameter sheaves located close to the stern.

During sea trials the tugs proved to have excellent manoeuvrability both ahead and astern, with the ability to move sideways at 4 knots. Arkad I and II have accommodation for a full 'live-aboard' crew of up to seven persons, complete with a spacious galley and well-appointed mess/lounge area on the main deck.

Uzmar currently have two further Robert Allan ASD tugs under construction and scheduled for delivery later this year. The vessels, one of 25m and a second of 32m, will have bollard pulls of 45 and 60 tonnes respectively.

Both will be equipped for harbour and terminal operation, escorting and fire fighting.