At the forefront of innovation for the global tug market

Kongsberg’s tailor-made manoeuvring and control systems present new opportunities for powerful, efficient tugs with more environmentally friendly technology solutions

  • Gunvor Hatling Midtbø
    Vice President, Communications

Ports around the world are beginning to target clean, emission-free operations. The International Maritime Organization (IMO) has adopted an initial strategy on the reduction of emissions from ships which envisages a reduction in CO2 emissions by at least 40 per cent by 2030, and that total annual emissions from international shipping should be reduced by at least 50 per cent by 2050 compared to 2008.

Tugboats play a vital part in ship assist, escort and pusher operations and must be both powerful and highly manoeuvrable for the role – but they too can play their part in reducing pollutant emissions, particularly in coastal areas.

Kongsberg Maritime is at the forefront of innovation to ensure that the global tug market embraces new opportunities for powerful, efficient tugs with more environmentally friendly technology solutions. Its array of complete manoeuvring and control systems include novel hybrid propulsion systems for tugs.

The first KONGSBERG hybrid propulsion system was installed on the Delta Teresa tug, with which San Francisco’s Baydelta Maritime has reported dramatic operational benefits on the water, as well as lower fuel consumption – a major win when operating in California where the pollutant emissions standards are among the strictest in the United States.

KONGSBERG’s long-standing partnership with Baydelta Maritime, and close cooperation with Jensen Maritime, Nichols Brothers Boat Builders and ABS, paved the way for an innovative, environmentally friendly hybrid tug capable of safe and reliable operations and maximum bollard pull.

The z-drive system, two KONGSBERG 255FP units, can accept power from the diesel engines, electric motors and from both power sources, enhancing the tug’s escort capability and providing unsurpassed assist support to the ultra-large ships that operate from the US West Coast.

The hybrid configuration reduces the power requirement and therefore the size of the engines needed for a tug the size of the Delta Teresa and provides greater operational flexibility which allows for the system to provide improved fuel efficiency and reduced emissions.

The hybrid arrangement provides power to US255 azimuth thrusters with ducted fixed pitch propellers that can be rotated 360 degrees around the vertical axis. This arrangement optimises omni-directional thrust and manoeuvrability as well as providing improved crash stop capability.

Photo: © Erik Larsen

Inboard portion of US255 azimuth thruster and the electric drive motor

Kongsberg Maritime’s azimuth thrusters are one of its most important products, providing mission-critical power and propulsion for some of the most innovative vessels at sea. They are produced in Rauma, Finland, where a multi-million Euro upgrade and refurbishment of KONGSBERG’s thruster manufacturing plant, consolidating production over a single site, created one of the world’s most advanced propulsion facilities.

KONGSBERG thrusters have become the choice for customers demanding high levels of reliability, power and performance in challenging environments. For Shaver Transportation, which serves the Columbia Snake River System in the United States, a focus on the environment and safety has encouraged the company to both upgrade existing vessels and invest in new state-of-the art tugs to fulfil its ship assist, inland grain and commodity transportation, and harbour services.

Working with Shaver Transportation, KONGSBERG supplied a tailored solution to upgrade its tug Portland, a 40-year-old ship assist vessel with a bollard pull of more than 50 tons, from UML to US205 thrusters – an investment in the propulsion system which has reinvigorated the tug for decades of operation, prolonging life and reducing emissions.

“On a journey towards zero emissions, our customers are looking for larger, more powerful, and efficient tugs with environmentally friendly technology and equipment. KONGSBERG is at the forefront of full-picture innovation for customers, spanning propulsion, deck machinery and energy solutions. Some of our customers in the US have now experienced real, operational and environmental improvements from our tug solutions and will see huge potential in long-term cost effectiveness.”
Yrjar Garshol, Vice President Global Sales & Marketing, Kongsberg Maritime

“There is no room for error with tugs, particularly in harbour areas, and they must be powerful and manoeuvrable. By combining diesel engines and electric motors, in addition to batteries, we offer our customers significant benefits including efficiency, environmental compatibility and flexibility in the propulsion system, which can be tailored to the customer’s specific requirements. Some of our customers in the US have now experienced real, operational and environmental improvements from our tug solutions and will see huge potential in long-term cost effectiveness.”

Baydelta Maritime – Benefiting from integrated hybrid propulsion systems

Baydelta Maritime has been serving San Francisco since 1982, offering ship assist, petroleum escort and general towing services throughout the San Francisco Bay area and offshore assignments. Baydelta tugs primarily escort and assist tankers to and from refineries north of San Francisco.

The California Oil Spill Prevention Act of 1990 established statutory Petroleum Tank Ship Escort requirements for regulations governing vessel movements in California ports and harbours. “The Exxon Valdez oil tanker was bound for Long Beach and that spill changed everything for our industry,” says Shawn Bennett, Baydelta’s General Manager. “Less well-known was the Cosco Busan oil spill in 2007, between San Francisco and Oakland. Our job is to keep the oil off the rocks. It’s a sensitive place where we do our work. We have specific requirements for power and for safety. We may be a small company, but our strategy is to have the best equipment and the best people to do that.”

The firm also builds vessels for charter to competitors, a programme which allows Baydelta to keep investing in state-of-the-art technology.

The drive to find the best equipment meant 18 months of research for the Baydelta team in preparation for the Delta Teresa tug build. Shawn recalls: “At the time, we were having lots of discussions with Caterpillar and KONGSBERG because of the EPA regulations for converting to Tier 4 diesel engines and we wanted the best performance solution. We were not comfortable with many of the options, such as batteries, available at the time. When we found this hybrid system, we went for this route – we liked what we saw. We built the keel and looked for the right engines for us. There was an excitement and energy around this and what was vital was that the stakeholders involved were on board the whole way through.”

A milestone for hybrid technology, the 100’x40’ tugboat Delta Teresa was designed by Jensen Maritime and built by Nichols Brothers, a replica of the Valor-class tugs ordered by Baydelta, but a dramatic departure with its innovative hybrid propulsion.

Baydelta’s Delta Teresa, named for the wife of Peter Zwart, Baydelta Maritime’s late Vice President of Operations, is the first tug to feature the Kongsberg hybrid propulsion system in the US, incorporating power take-in, electric motors, main propulsion engines and Kongsberg US255 azimuth thrusters with ducted fixed pitch propellers that can be rotated 360 degrees around the vertical axis, producing optimal omni-directional thrust and manoeuvrability.

Baydelta’s tugboats, with their variable power demands and work in California’s ports, where reducing emissions are a priority, were an ideal chance to put Kongsberg’s integrated hybrid propulsion packages to the test. The tug features the same ship assist and tanker escort capabilities of existing Valor-class harbour tugs, but with multiple operational modes – diesel-mechanical, diesel electric, or combined mechanical electric – enabling Baydelta to save fuel and reduce emissions, while supplying the same power and vessel characteristics needed for power and finesse in operations.

The hybrid propulsion system offers the possibility of being able to manoeuvre very precisely using the electric motor, or to deliver a powerful bollard pull using the entire power output of the diesel engines and electric motors combined. 

Shawn says: “There have been a lot of operational benefits we didn’t expect with the hybrid propulsion system. The main engines are only being used for the main job and then shut off. There is an immediate response by the propellers, and the electric motors can slow everything right down to 1rpm for gentle operations, with the manoeuvrability proving to be really good. If conditions are too rough or windy, we can use the main engines. And everything can be done remotely, at the touch of a button, from the wheelhouse. After the immediate learning curve that comes with using new technology, we have found this system to be operationally really beneficial.”

Commercial Director Ralph Silverman adds: “We are seeing a lot less disturbance of the water and great manoeuvrability in tight areas. Delta Teresa is an elephant that can do ballet.”

Although the tug’s Tier 3 Cat mains lack the aftertreatment system found in newer Tier 4 models, Baydelta is also reporting lower emissions and fuel consumption from the hybrid system on the Delta Teresa. Operations Manager Fred Ellingson explains: “After operating for about 18 months, we have compared the performance of the Delta Teresa with one of the sister boats, which is a standard Valor-class tug. What we have found is that when both boats are operating under the same conditions and parameters the Delta Teresa is making significant savings in the amount of fuel burned, which should equate to lower emissions.

“There is a big push to move forward now. Understanding the new regs is pretty important for us next year. California has the strictest regulations, which are a real challenge for us to meet but they are doing a good job in trying to clear everything up.”