The Harbormaster Tunnel Thruster runs at 1200-1400 RPM input (horizontal or vertical). It consists of a right angle gear set, an accommodating watertight pod (gear case) assembly, pod supporting structure, propeller and corrosion resistant steel tunnel.


The gears are a lapped matched set of spiral bevel design, manufactured in the USA to comply with AGMA quality standard 8-10.


The pinion and propeller shafts are forged steel and supported by tapered roller bearings sized to provide extended bearing life.


A mechanical type propeller shaft seal is used to insure against the incursion of seawater.


The tunnel accepts a 48-inch diameter propeller. The propeller is a four blade manganese bronze Kaplan type having a maximum speed of 492 RPM. The thrust produced at that speed will not be less than 9,400 lbs.


The tunnel is rolled of abrasion and corrosion resistant steel with a minimum thickness of of an inch. Chill rings rolled of 1 X 3 inch stock are welded to the thruster ends to function as heat sinks to minimize distortion during installation welding. To insure proper alignment of the tunnel extensions, the chill rings are arranged on the thruster to provide a pilot I.D. for the extensions to be installed by the shipyard.


Lubrication of the gear set and bearings is accomplished by oil immersion. A 10-gallon static lube oil tank is provided for installation by the shipyard as part of the lubrication system. The tank should be mounted a minimum of 10 feet above the load water line to insure that the static head imposed on the propeller seal by the lubricating oil will always exceed that imposed by the sea water.


To insure adequate water flow to the propeller, the ratio of pod to tunnel diameter does not exceed 3:1.


The thruster is warranted to be free from defects in material and workmanship for a period of 12 months from the date of delivery and acceptance.


Replacement parts are readily available from Harbormaster Marine, Inc.


All material manufactured and assembled in the USA.





Harbormaster Marine, Inc

31777 Industrial Road Livonia, MI 48150 USA Telephone: (800) 898-5387 Fax: (734) 425-1850