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The World’s First Re-Chargeable All Electric Harbour Tug

With today’s increasing earth pollution, most technologies are being developed with greener solutions. The marine use of LNG and Hybrid solutions for a greener world are currently the most popular technologies. As a result of the current maneuvering applications, it is observed that less emission amount is achieved at low loads. By using LNG and Hybrid technologies, the oscillation at these low loads can be eliminated only to an amount of 50%.

100% Clean Power ZEETUG!

No noise. No emissions. Just efficient operation.

A revolutionary for the new generation fully green tugboat has been developed by NAVTEK Naval Technologies. ZEETUG with zero emission, reliant solely on battery power for bollard pull is the world’s first re-chargeable all-electric harbor tug.

NAVTEK General Manager Mr. Ferhat Acuner says: GISAS, the Pilotage & Tugboat Company located in Tuzla-ISTANBUL, was planning to replace four of its existing tugboats with smaller and environment- friendly tugboats, thus was also signaling a long-term commitment towards curbing emissions in and around the Tuzla shipyards’ and ports’ zone.

We considered the demand and it was a challenge to fit the hybrid solution to a 10% smaller tugboat request. Therefore, we decided to investigate whether a zero-emission electric vessel is technically possible. The next step was to consider the feasibility of full-electrical operation from an engineering perspective...

Our research and development methods relied on two main approaches of analysis. One was the numerical tool developments based on unsteady CFD computations, both aerodynamics and hydrodynamics. The other one was the prototype and field experiments. Power requirement information for 21 different maneuver options were obtained from real tugs and the net power measurements were made on the shaft.

These experimental analysis results allowed the support and development of the numerical tools regarding tugboats operating range, operation time, distances to be sailed and basic power requirement during all maneuvers of a tugboat. We spent a significant amount of time to develop this innovative tugboat, then we came to the conclusion that ZEETUG (Zero Emission Electric Tugboat) was technically possible.

The 18.7 mts., 30 t BP ZEETUG is equipped with a Corvus Orca energy storage system (ESS), comprising two battery packs manufactured by green craft tech specialist Corvus Energy. Featuring a total energy storage capacity of 1,484 kWh, the ESS feeds two 968 kWe Siemens propulsion motors using fixed-pitch propellers. ABB was contracted to provide the DC/DC inverter/converters and drive system. The State-of art design of the electric system and the assembly of the combined propulsive package was overseen by Turkish marine electric systems integrator BMA Technology, which also provided a back- up alarm monitoring and control system. To ensure absolute safety the tugboat also has a 100-kW generator set. It provides enough power for the tugboat as take-me-home device in the event of an electrical system failure and if the vessel needs to fire fight in meantime.

ZEETUG can undertake harbour towing duties during daytime and can be re-charged overnight. One charging per day, via shore-side connection QCS (Quick Charge Station). The batteries can be fully charged in less than 1 hour through QCS, but it can also be charged through the shore connection and/or genset. The QCS was also made by NAVTEK.

On the other hand, our commitment to reduce emissions must be more than just words for a business that needs to make profit. The cost of operating an electric tugboat is up to 85% less than running a diesel tugboat.

In 5 years by replacing their 4 diesel tug boats with ZEETUG’s GISAS anticipates savings around 1.700.000 US Dollars in the operation costs.

Turnkey Delivery For GISAS's Operation Needs

Operational Facts:

  • Smaller than similar Tugs (18.7 m in Length against 21 m for typical 30 t BP Tugs)

  • Operational Costs drop down to about 85% of a diesel engine driven similar Tugboat.

  • One charge is enough for standard daily operations

  • Charging time is less than 1 hour

  • Battery Packages’ life ‘10 years’

All electric, battery powered ZEETUG can be custom built for any kind of operation needs from 5t BP to 80t BP.


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