Harley Marine Services, a fast growing Seattle-based company in the maritime transportation services business, turned to Caterpillar to get a complete power and propulsion system designed specifically for tug operations.
They ordered four Cat 3516 marine propulsion engines and four Cat Propulsion MTA-T (Marine Thruster Azimuth – Tug) rated drives, which will power two new Harley Marine harbor tug vessels currently under construction at Diversified Marine Incorporated, a shipyard in Portland, Oregon.
“Much of Harley Marine’s fleet is powered by Cat engines, and with the construction of these two new vessels, they’re adding our tug-specific propulsion solution as well,” said Emil Cerdier, sales manager for Cat Propulsion. “Getting a complete package from one supplier simplifies the design, installation, and service support, allowing Harley to rely on the Cat dealer network as a single point of contact for the entire powertrain system.”
Each Harley Marine harbor tug will feature a pair of 3516 engines, each delivering 1920 kW at 1600 rpm and two MTA 524-T thrusters with a 2,400mm propeller diameter.
The MTA 524-T is a new version of the previous MTA design specifically optimized for the operation profile of a tug. The “Tug” rated drives include features to maximize bollard pull, simplify installation and maintenance, and increase maneuverability. The Harley Marine units will be delivered with custom-made fixed-pitch propellers and a PTO-powered steering and lubrication system. Cat Propulsion’s complete package for tugs includes engines, high-speed shafting, clutches, and controls. The display consoles for the control system will also control engine and thruster functionality.
Cat dealer Peterson Power led the efforts on the project, helping refine the specifications and supporting the installation and service of these systems. Further enhancing the total Cat Solution, Cat Financial is providing complete vessel financing throughout the construction and term of both tugs.
The Cat engines and thrusters are expected to deliver in mid-2016, with vessel deliveries in early 2017.
Strenght and performance: the optimal choise for marine applications
Silvia Chiarito
August 12, 2026
The sea is one of the most fascinating natural elements, yet it is also one of the most challenging for both humans and their technology. Vessels operating continuously in a saline and constantly changing environment require robust and sustainable solutions.
