Navtek Naval Technologies has laid the groundwork for the future by designing and building the world’s first all-electric tug, ZEETUG® – short for Zero Emissions Electric tug.

It started with two – superficially straightforward – renewal requests: Gisas Shipbuilding asked for harbor tugs that were both “lower emission and smaller size” than its previous fleet. The tugboats have to meet a rising environmental awareness along with a particularly tight operating environment inside the Port of Tuzla, Istanbul.

Built at Navtek’s parent company TK Tuzla Shipyard for Turkish owner GISAS Shipbuilding Industry, the first ZEETUG®, Gisas Power, went into service this year, operating in the shipyard zone in the Port of Tuzla, Istanbul. Designated a ZEETUG®-30 design for its 32 tonnes of bollard pull, Gisas Power has an overall length of 18.7 m, beam of 6.7 m, depth of 4.7 m and design draught of 3.5 m, with a service speed of 10 knots.

With the aid of a modular system, ZEETUG® has an integrated electrical propulsion system available to be tailored to the client’s specific operation profile (from 5T BP to 75T BP).

ZEETUG-30 draws all its power from two 1,450-kW lithium-ion battery packs supplied by Corvus Energy. For safety, the tug has two redundant battery rooms, one forward and one aft, which are maintained at a constant temperature by an air cooling system. ZEETUG® has been designed and built according to Turkish Lloyd’s rules, and meets any IACS member classification society’s valid and related requirements.

To optimize electric power consumption, analyze the operational profile and extend the range of the electric tug, Navtek designed the Smart Tug Energy Management System (STEMS). The STEMS software monitors ZEETUG®’s performance via an onboard data acquisition system. It tracks tug speed, motor speed, power consumption, battery-motor temperature, and battery state of charge, providing feedback and suggested actions to the captain.

Remote monitoring and diagnostics allow technicians and engineers to resolve any issues in real-time. Within hours, we are able to perform updates across our entire client fleet.

A full charge for the tug can be accomplished in one hour by a quick-charging station. The time it takes to charge a ZEETUG® varies based on the charger used, like other electrical devices. We adjust the technical characteristics of ZEETUG® according to the existing operating profile and needs/requirements of our clients. The QCS (quick charge station) is also designed and built by Navtek.

Compared with similarly sized diesel-mechanical tugs, the all-electric ZEETUG®-30 is expected to save 210 tonnes of CO2 emissions and nine tonnes of NOx emissions in a year.

ZEETUG® is a budget-friendly green technology, and the 85% lower operating cost of its full-electric propulsion system is also a real benefit for the operator. The return period of investment is amazing.

Further, the high power output comes with a significant increase in comfort levels, with no noise, no vibration and no emissions! Just efficient operations.

Our solution partners are BMA Technology (the electrical systems integrator), Corvus Energy (the battery supplier) and ABB (the drive and converter supplier). We want to thank Gisas Shipbuilding Industry for their trust in choosing us. We have two more 30T BP and one more 45T BP ZEETUG’s in our order book for our good client Gisas. The construction on these follow-on vessels will start in 2020.

BY THE MARITIME EXECUTIVE 08-04-2020 02:36:00