For some time there have been increasingly vocal demands for powerful escort tugs to operate in the Bosphorus and Straits of Istanbul, where heavy shipping traffic passes between the Black Sea and the Sea of Marmara.

The vessel is the first of the new ASD 34/70 class stern drive tugs designed by Robert Allan Ltd of Vancouver. With a length of 34m overall, a moulded beam of 11.60m and a maximum draft of 5.26m it was built by the Turkish Yardimci Shipyard at Tuzla. The hull form is to a well-established design developed by Robert Allan for optimum performance while operating ahead and astern.

To enhance the indirect towing performance in the escort role the vessel is fitted with a long, deep skeg. A semi-raised foredeck affords good sea-keeping qualities and the bow is protected by heavy two-stage rubber fendering.

Two Deutz MWM type SBV 9M 628 main engines running at 1000rev/min develop a total of 5500bhp. Power is transmitted to a pair of Schottel SRP 1515CP fully azimuthing propulsion units to give the vessel a bollard pull ahead of 65 tonnes ahead and 55 tonnes astern.

TDI Zubeyde Ana is fitted with two towing winches, one forward and one aft, supplied along with the stern roller and other deck equipment by Turkish manufacturer Data Hidrolik.

Both winches have a brake holding load of 130 tonnes.

A 65-ton Mampaey quick release towing hook, remotely controlled from the wheelhouse, is fitted aft for secondary use. Electrical power onboard is supplied by two MAN powered generator sets rated at 160kW.

The new tug is equipped for fire fighting to FiFi 1 standard and fitted with two Skum monitors mounted on a platform above the exhaust uptakes and a self protection spray system around the superstructure.

Each water/foam monitor has a capacity of 1200m 3/hr and the entire fire fighting system is supplied by two Unitor pumps driven by the main engines via Norgear 'step-up' gearboxes.

Eight tonnes of chemical oil dispersant is carried in a dedicated internal tanks and can be dispensed by means of spray booms. A further tank has capacity for 41 tonnes of recovered oil.