Navtek developed STEMS to manage energy and monitor performance on all-electric harbour tugs
Navtek Naval Technologies has developed a vessel power management and condition monitoring system for its range of Zeetug vessels.
Its first all-electric newbuilding Gisas Power was built by TK Tuzla Shipyard for Turkish owner GISAS Shipbuilding Industry in 2019 to a Navtek Zeetug-30 design.
This 18.7-m harbour tug has two 1,450-kW lithium-ion battery packs supplied by Corvus Energy and 32 tonnes of bollard pull. Managing the batteries’ charging and power distribution is Navtek’s smart tug energy management system (STEMS).
Navtek general manager Ferhat Acuner said STEMS uses data from vessel systems and its operating environment to provide information to managers.
“STEMS processes all this data,” he said. “Data is transferred to a shore data centre through a virtual private network (VPN).” Data is also transmitted to tablets with Android operating systems for crew and managers to visualise tug performance.
“STEMS is both a browser-based and a mobile software, which has a lot of capabilities for fleet control and tugboat operators,” said Mr Acuner. “With its flexible structure, it can be adapted to any fleet.”
Data is collected from the tug’s integrated automation, energy management and propulsion control systems through Modbus TCP/IP links to the VPN router. This transmits data over wireless communications, such as 3G/4G mobile networks, to a shore data centre. This centre collates Automatic Identification System (AIS) information, weather reports and shore radar data and integrates this within STEMS.
STEMS uses related information and performance data to optimise the electric power for specific tug and electric motor speeds, power consumption requirements, battery state of charge, weather and actual ambient conditions, enabling operators to monitor energy consumption and alert managers to any issues. Operators can estimate the final charge of batteries and change the predefined route on charts depending on power availability.
STEMS can prepare reports of all operational output and displays real-time weather data from ground stations on tablets.
“It monitors all data related to the performance of the tugboat and provides feedback,” said Mr Acuner. “There are reporting tools for operation and personnel performance.”
As more Zeetugs are built, STEMS could be used to control and manage an entire fleet of these vessels.
Mr Acuner is expecting more Zeetugs with STEMS to be built in the future. “Electric-driven, smart ships are the future,” he said. “In five years from now, there will be many more smart electric ships than anticipated.”
He also expects these Zeetugs to have more autonomy. “STEMS shows us the future for autonomous operations,” he said. “We are developing software for future projects and we will see better software applications.
Zeetugs could be built with higher battery capacity and bollard pulls. Navtek has another version in the pipeline. Mr Acuner said the next project is likely to be Zeetug-45. This would have around 45 tonnes of bollard pull and 2 MWh battery capacity, “depending on its operating characteristics and where it will operate” said Mr Acuner. “We would also need to know if there are escort and fire-fighting requirements.”
Naval architects are also researching Zeetug-5, Zeetug-20 and Zeetug-60 designs.
Mr Acuner presented STEMS during Riviera Maritime Media’s Smart tugs: the industry’s Tesla, or still on the test bed? webinar, on 1 September, part of Riviera’s Tug Technology Webinar Week.