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.”
