Cummins Powered RAstar 3500 with 8400 HP


Cummins Vessel Reference #825


Early in 2017 a shipyard in Spain delivered two state-of-the-art water-jet catamaran crew boats. Each boat had 16,000 HP derived from four of the Cummins Engine company’s new QSK95 marine diesel. Following several years in development, the engine has proven itself in this high-speed application. The QSK95 is certified to IMO Tier 11 emission standards.



To round out the offerings, while demonstrating the versatility of the QSK95, Cummins has contracted the naval architect firm of Robert Allan Ltd. to prepare drawings of their proven RAstar 3500 tug design with a pair of the QSK95 engines for power. The design and the engines are a good match.


These high-speed, 1800 RPM, engines each deliver a remarkable 3132 kW (4200 BHP) at only 13,282 kilograms (29,282lbs) of weight. This is the same horsepower range that some recently delivered ocean towing tugs have been using as well.

The RAstar 3500 tug design has earned a respected role in escort and ship handling duties due to its innovative hull design among other features. Multiple ports in such diverse locals as China’s Tianjin Port and Western Australia’s Port Hammond have adopted tug in the RAstar class.




To suport the combined 8400 HP of the Tier II compliant QSK95 engines, these are, at 34.94 by 14.75-meters, big tugs. The Cummins engines will turn 3200 m/m, four-blade Kaplan, azimuthing propellers in 19A type nozzles through a reduction of 8.476:1. With this configuration, in computerized testing carried out by Robert Allan Ltd, this tug design delivered a remarkable 96-tonne bollard pull astern and 102 tonnes ahead. The model also generated an estimated 14.2-knot free running speed with a 4.5-meter light draft. The tugs normal draft for navigation would be 6.49 meters.

Using the Robert Allan designed skeg on the hull and the staple arrangement on deck, as has been demonstrated with similar tugs currently in service, an escort tug powered by a pair of Cummins QSK95 engines has become an attractive option. As designed, the escort/offshore terminal tug would have two Cummins QSK19 powered generator sets for ship’s power and for the 400 hp hawser/escort winch on the tug’s bow. A single CumminsQSB76.7 would meet the tug’s hotel demands when in port.

For the design and renderings, Cummins executives have chosen the name of the company’s founder, “Clessie L. Cummins” in honor of the QSK95’s contribution to the firm’s tradition of innovation and meeting new challenges.


Renderings courtesy of Robert Allan Ltd.



For further information:


Andy Kelly
Marketing Communications Manager
Consumer, Marine & Infrastructure Segments
Cummins Inc.
4500 Leeds Ave. Ste. 301
Charleston, SC 29405
Office Phone: 843-745-1172
Email: [email protected]

Alan Haig-Brown

Alan Haig-Brown

Over 30 years as an author for global commercial marine and fishing publications backed with hands-on experience on commercial fishing boats and coastal freighters makes Alan Haig-Brown uniquely qualified to provide vessel reference articles for Cummins Marine. You can find him in shipyards around the world, and on his own website,

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