­Jensen Maritime, a Seattle-based naval architecture and marine engineering firm, was recently selected to design Baydelta Maritime’s new 100-foot, Z-drive hybrid tug.

The new tug will use Rolls-Royce hybrid technology and will be the first installation of a hybrid system for Seattle-based Nichols Brothers Boat Builders, and the first hybrid tug designed by Jensen to enter the construction phase.

“Jensen is proud to have been chosen as the design firm on this project, and we look forward to seeing the vessel through from concept to completion,” Bryan Nichols, director, business development, for Jensen Maritime, said in a statement. “We are pleased to be working with longstanding partners Baydelta and Nichols Brothers on this historic build. This tug will meet the industry’s demand for strong, yet nimble vessels with the quality design that customers expect from Jensen.”

Scheduled for delivery in the first quarter of 2019, the tug will feature the same ship assist and tanker escort capabilities of existing Valor-class harbor tugs, but with multiple operational modes. The Rolls-Royce hybrid system will permit the vessel to operate in the direct-diesel, diesel-electric or fully-electric mode while assisting the large containerships and tankers that call at U.S. West Coast ports. This concept will save fuel and reduce emissions, while supplying Baydelta with the same power and vessel characteristics needed for their operations. The flexibility provided by the drive system will allow loitering and transit at up to 7-8 knots in electric-only mode, then a bollard pull of 90, or nine short tons, in combined diesel-electric mode.

The tug will be powered by two Caterpillar C3516 C Tier 3 diesel engines, each rated at 1995 kW at 1,600 rpm (5,350 total hp), supplied by Peterson Power, Portland, Ore.; and by two Rolls-Royce supplied 424-kW electric motors. The Z-drive system, two Rolls-Royce 255FP units, can accept power from the diesel engines, electric motors and from both power sources. The electric motors are powered by three Cat C9.3 generators with 300 kW each, which are 480V three-phase at 1,800 rpm, and one harbor generator, a Cat C7.1 150 kW 480V, three-phase at 1,800 rpm. All four generators will be supplied by Peterson Power.

The tug will have eight berths. Major equipment on board will include a Rapp Marine electric hawser winch and a single drum tow winch. The tug is designed to carry up to 71,000 gals. of fuel and 4,300 gals. of fresh water. It will have a large pilothouse with all-around visibility; a deckhouse with an open feel; a large mess and lounge area; and accommodations for an eight-person crew.

The tug will be ABS Load Line classed and compliant with U.S. Coast Guard regulations. Jensen is owned by Crowley Maritime Corp. San Francisco-based Baydelta Maritime built the $10.4 million Delta Audrey at Nichols Brothers in 2014. The Delta Audrey is a 100'x40', 6,700 hp Z-drive. Nichols has built several 6,700-hp Z-drives for Baydelta.