Cummins Hotips#802      December 2016

Jensen Design

Jensen Design and Rendering

Shipyards, especially those that repair and construct larger vessels, invariably need to move the vessels, materials and other resources about the yard. To do this, yards often have a small yard-tug that can maneuver in and around yard structures such as for repositioning bulls into dry docks or to control newly launched vessels.

Flying bridge

Flying bridge

As one of the United States largest shipbuilders, General Dynamics NASSCO’s San Diego shipyard has been well served by the venerable tug Mr. Ed. But when the time came to replace this valuable yard asset, the yard management decided to do it right. Approaching Seattle’s Jensen Design, through the Marine Group Boat Works, they had a vessel designed specifically for shipyard work robust enough to endure long hours each day while minimizing the resources needed to operate and maintain it. The resulting tug is an attractive, compact, steel-hulled boat that can be operated by a single person.

Tow bitts fore and aft

Tow bitts fore and aft

The 38’ by 15’ by 5.5’ tug is currently under construction by San Diego-based boat-builders Marine Group Boat Works at its new solar-powered construction facility in National City, California— conveniently located less than five miles from NASSCO. In addition to moving other vessels,, the new tug will be responsible for deploying pollution containment booms. Work in the often-tight corners of a shipyard requires excellent visibility, so the designers have given the pilothouse a 300-degree unobstructed line of sight. In addition, a flying bridge, complete with communication and control consoles, is an integral part of the wheelhouse.

For pulling power, the tug will have a pair of Cummins QSL9M Tier 3 engines each producing 410 horsepower. The engines turn 38 by 26-inch four-blade, bronze, workhorse-style props on 3-inch Aquamet 22 shafts. Each engine is linked to the shafts with a ZF325-1 gear with 2.97:1 ratios.

The combined 820-MHP propulsion is expected to give the tug a speed between 9 and 11 knots. It will also deliver between 18,000 and 20,000-pounds of bollard pull. On-deck tow-bitts are mounted fore and aft to exercise the pulls.

In addition to conventional rudders the tug will be fitted with flanking rudders for enhanced maneuverability and handling. Tankage will include 1000 gallons of fuel. A Fast Lube Oil Change System (FLOCKS) negates the need for lube and dirty oil tanks. There will be a 5-kW 110-volt generator for electrical requirements. Delivery of the currently designated Workboat 38 is scheduled for summer 2017.


Renderings courtesy of Jensen Design


Bill Shepard

Marine Account Manager, Pacific Region

Cummins Sales and Service

1939 Deere Ave.

Irvine, CA 92606

Phone: 949 253 6017

Mobile: 949 337 5248




Mr. David Barbat

Sr. Facilities Engineer

General Dynamics, NASSCO

Phone: 619 544 3535

Cell: 619 241 3101




Marine Group Boat Works, LLC

997 G Street,

Chula Vista, CA 91910

Phone: 619 427 6767




Jensen Maritime,

1102 SW Massachusetts St.

Seattle, WA 98134


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