The new vessel was developed by Damen's Tug & Workboat project team in the Netherlands at Gorinchem and is the result of much market research, calculation and tank testing.

Once the design was finalised Damen Changde was given the task of constructing the first two prototype vessels. China was chosen as the venue for construction in the expectation that the new vessel will meet particular demands for this type of tug in the Far East and Australasia.

Barunga is a vessel of 24.55m in length overall, with a beam of 11.49m, and a maximum draft of 5.15m, designed for operation by a small crew. The hull form incorporates several features found in other well-established Damen ASD tugs.

These include a smooth, rounded, form with a heavily chamfered stern and deep box keel. An unusual design of aft skeg is an open extension of the box keel to facilitate docking supported by two struts in a 'V' configuration.

This arrangement is intended to enhance course stability without degrading the ability to side-step or turn.

Two Caterpillar 3516B TA HD/MC main engines provide 5632 brake horsepower to drive a pair of Rolls Royce US 255 propulsion units. Power is transmitted through Twin Disc MCD 3000-3 LD slipping clutches to drive the 2600mm diameter propellers of the fully azimuthing units. On trials this first tug of the new series achieved a bollard pull of 68.2 tonnes ahead and 63.0 tonnes towing astern, with an almost identical free running speed of 12.8 knots ahead and 12.7 knots astern.

The main engines and propulsion units are widely spaced in the sizeable engineroom, with a shaft line that has been kept as straight as possible. Located between the main engines are two Caterpillar 3304B T generator sets rated at 106kVA, 50Hz, 400v, each. A further Caterpillar 3306B TA powers the fire fighting pump, supplying 600cu/m/hour at 10 bar to a single manually operated monitor at bridge deck level.

tows while shiphandling from a hydraulically driven, split drum, Kraaijeveld winch and anchor-windlass on the foredeck. The two-speed winch has a line pull of 18 tonnes at 11m/min or 9 tonnes at 22m/min, with a brake holding load of 150 tonnes. A 5 tonne electrically powered capstan is provided on the afterdeck along with a Mampaey quick-release towing hook of 100 tonnes safe working load.

With the successful trials and sale of this first ASD 2411 to Adsteam, plans were immediately put in place to complete the second vessel at the Changde shipyard and start construction on the hulls and major steelwork for four more tugs of the same type.