VESSEL REVIEW | Yonggang Tuo 80 – Hybrid tug to serve China’s Ningbo-Zhoushan Port

China's Jiangsu Zhenjiang Shipyard has delivered a new harbour tug to local operator Ningbo Oil Port Barge for use in the East China Sea port of Ningbo-Zhoushan in Zhejiang province.

Yonggang Tuo 80 has an LOA of 39 metres, a beam of 10.6 metres, a depth of 4.9 metres, a design draught of 4.15 metres, a gross tonnage of 576, and a hybrid propulsion system capable of various operating modes. Duties will include escort and berthing/unberthing assistance for large ships.

The tug uses a parallel diesel-electric hybrid propulsion arrangement, which consists of a 3,680kW main diesel engine, lithium battery-powered motors, and an azimuthing thruster. Hybrid mode will permit more optimal use of the diesel engine for satisfying towing requirements while fully electric mode will be reserved for when the tug is operating in an emission control area.

In diesel-only mode, any excess power generated by the main engine will be allotted for charging of the batteries, thus minimising heat loss and further reducing emissions, though the batteries also have shore charging capability for greater operational flexibility.

A boost mode is also available wherein the batteries will augment the main engine to increase the sailing speed. The hydrodynamic performance of the main thruster meanwhile ensures significant bollard pull is maintained even when the tug is at maximum draught. The propeller assembly has even been reinforced to better protect against sediment in port waters. The propeller and the shaft were provided by Nanjing High Accurate Marine Equipment.

Trials showed that Yonggang Tuo 80 can sail up to 1.5 hours at 10 knots in fully electric mode. The test sailings also proved the tug's ability to achieve energy savings of greater than 15 per cent compared to tugs that run on conventional fuel oil. Emissions reductions figures that were achieved during the trial phase include 35 per cent for particulates, 15 per cent for CO2, and 25 per cent for NOx.

The tug is also equipped with advanced intelligent energy efficiency management and safety assistance systems, which can aid in the analysis of vessel performance.