VESSEL REVIEW | Sparky – All-electric tug delivered to New Zealand’s Auckland port

New Zealand port operator Ports of Auckland (POAL) has taken delivery of a new electric-powered, reversed stern drive (RSD) tug built by Damen Song Cam Shipyard in Vietnam.

The aptly named Sparky was designed by the Damen Shipyards Group to have an operational service life of 25 years. It will be used for ship handling duties at Auckland, New Zealand's largest container and international trade terminal. The acquisition of the all-electric tug is in line with POAL's goal of significantly reducing its vessel fleet's emissions by 2040.

Sparky has a length of 24.73 metres, a beam of 13.13 metres, a draught of six metres, a speed of 12 knots, and a bollard pull of 70 tonnes. The tug draws power from 2,240 Echandia lithium-titanium-oxide (LTO) batteries with a total rated output of 2,784 kWh. The batteries supply power for two Kongsberg Maritime US 255 azimuthing thrusters that house 3,000mm, four-bladed propellers. Damen said the thrusters are mounted at a slight angle for optimal performance.

For redundancy purposes, the batteries are arranged in strings. If one battery in a string were to fail, the others would simply shoulder the load.

Echandia said the batteries will enable the tug to achieve CO2 emissions of approximately 465 tonnes each year. POAL meanwhile expects up to four shipping moves can be completed on a single full charge of the batteries while the recharge time is approximately two hours. The charging infrastructure was supplied by the McKay Group, which was also responsible for the electrical installation of the tug's onboard HVAC setup.

To ensure added safety, the tug also has two 1,000kW back-up generators that will only be used in cases of emergency or other unforeseen faults. POAL expects to use the generators only rarely, once or twice a year at most.

The owner added that the cost of operating Sparky is less than a third of the cost of operating a diesel tug.

The deck equipment includes a double drum towing winch with a 30-tonne pull and 200-tonne brake. The winch was developed in-house by Damen.

The tug also boasts an obstacle-free working deck and a wheelhouse that offers improved all-round visibility and is fitted with Damen's patented high-impact resistant safety glass. As the vessel is designed to sail bow first, a higher freeboard was incorporated to improve seakeeping.

Cloud-based remote monitoring allows POAL to be updated on the tug's disposition, especially when maintenance becomes necessary.

Sparky was designed in compliance to Bureau Veritas' Battery System and Electric Hybrid notations.

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