Hydraulic Tunnel Thrusters White Paper

Hydraulic tunnel thrusters are available from 16″ to 86″ diameter and range from 35 to 2000 HP. The hydrostatic transmission provides proportional propeller speed control in both directions, thereby eliminating the need for controllable pitch propellers.

Each thruster comes as a complete package, with a short tunnel assembly and a robust four-blade, high-thrust propeller on a large diameter shaft.  The shaft is directly driven by Thrustmaster’s exclusive hydraulic propulsion motor.  The motor is housed inside the dry pod of the thruster.

Each thruster is available in steel (for steel hulls) or in aluminum (for aluminum hulls).  The steel thruster uses a steel tunnel and bearing housing, an Aquamet® propeller shaft, 316 stainless steel seal housing, manganese bronze or NiBrAl propeller, and stainless steel hardware.  Steel parts are provided with a serious marine coating (Ameron polyurethane over epoxy on inorganic zinc primer), and the inside of the tunnel is provided with a ceramic coating for extreme corrosion and erosion protection.

The aluminum thruster uses a tunnel assembly, strut, pod and bearing housing of marine grade aluminum.  Other than that, it is the same as the steel thruster.

Precise Control When You Need it Most

Tunnel thrusters are primarily used for docking and undocking, slow speed maneuvering, emergency steering and station-keeping at zero or slow forward speed. Tunnel thrusters provide a significant advantage to vessels where adjustments in their heading at zero speed are critical to their operation, where maneuvering in tight quarters is required of where frequent docking occurs.

Thrustmaster hydraulic tunnel thrusters are designed for heavy-duty seawater service.  They are used in fishing trawlers, ferries, offshore supply vessels, crewboats, river cruise vessels, sightseeing boats, bunkering tankers, and military craft, to name a few.

They are built to last for the life of the vessel.  Many units are used in dynamic positioning applications where they work continuously around the clock.  They can be used in pairs or multiples for easy installation in skegs of larger vessels or in the bow of vessels with limited draft.

Smooth and Forgiving Hydraulic Drive

Thrustmaster of Texas, Inc., pioneered the concept of hydraulic propulsion for the marine industry using technology originally employed in the offshore oil fields. Thrustmaster’s hydraulic bow and stern thrusters are the benchmark for efficient and reliable maneuvering under severe marine conditions.

The hydraulic drive is extremely resistant to damage. Foreign objects ingested by the tunnel, (a disastrous event with a mechanically-driven bow thruster) will not damage the hydraulic drive train, as the hydraulic system instantly relieves any transmission overloads.

The variable-flow hydrostatic drive system allows for infinite propeller speed control in port and starboard direction. This allows perfect vessel station-keeping as well as instant thrust response. Full thrust can be reversed within three to five seconds. This instantaneous and fully proportional speed control gives performance better than a controllable pitch propeller (CPP) without the cost, complexity, fragility or maintenance problems of the intricate CPP control system with all its drive shafts, levers and feedback mechanisms.

Thrustmaster hydraulic tunnel thrusters require no routine maintenance, and rebuilds are recommended only once every 40,000 hours of operation.  Very few tunnel thrusters reach 40,0000 operating hours before their 20th year of use.

Efficient and Reliable

Thrustmaster’s hydraulic drive is simple, quiet, efficient and extremely smooth. The prime mover driving the hydraulic pump can be a non-reversible electric motor or an engine running at constant speed because the hydraulic transmission controls propeller speed and direction of rotation. The prime mover drives a hydraulic pump. The propeller is driven by a hydraulic motor. In between are fluid conductors. There are no drive shafts, gears, bearings or other mechanical components to fail. The hydraulics are virtually maintenance free and provide years of reliable operation while performing in the harshest marine environments.

Many Thrustmaster tunnel thrusters have been in continuous commercial use for more than 20 years, providing flawless operation without any component failures.

There are very few rotating parts. The simple design of the direct hydraulic drive, without right angle gear transmission or drive shaft, provides for extreme reliability and very easy maintenance. There is no scheduled maintenance to the tunnel thruster other than normal maintenance to the hydraulic system and prime mover. Because all bearings are lubricated by the hydraulic fluid, there are no grease points or oil levels to check. The hydraulic transmission separates and dampens engine and propeller vibrations.

Superior to Diesel-Electric

Thrustmaster’s hydraulic tunnel thrusters are superior to diesel-electric driven thrusters in terms of response, efficiency and maintainability. Moreover, hydraulic propulsion is more affordable in many applications.

The units are available in steel or aluminum construction. They come complete with a section of tunnel, facilitating easy installation.

Thruster design and construction is in accordance with the United States Coast Guard, American Bureau of Shipping, Lloyd’s Register and other major classification society rules. Certification to a specific class is available as an option.

FACT
Two smaller hydraulic thrusters often cost less than one thruster twice as big.  Two or more thrusters can be operated in unison, as if it were a single thruster, saving money while providing redundancy.

Flexible Convenient Installation

A Thrustmaster hydraulic tunnel thruster can be installed at its most favorable location while the prime mover with hydraulic pump can be installed in the engine room or any other convenient location, optimizing weight distribution and eliminating the requirement for a separate thruster room or additional inspected machinery space. There are no shafts or couplings to align or requirements for additional ventilation, lighting or floor gratings.

You may use a simple AC induction motor or an auxiliary drive off a generator or main propulsion engine. Alternatively, a separate dedicated thruster engine without a clutch or marine reversing gear may be used to drive the hydraulic pump.

Hydraulic Systems

Thrustmaster tunnel thrusters can operate in either open or closed-loop hydraulic systems at intermediate to high pressures. A dedicated thruster hydraulic system is not necessarily required. An existing hydraulic system on the vessel may be used to drive the thruster.  Alternatively, Thrustmaster can furnish a system that powers a variety of vessel devices in addition to the thruster, including deck cranes, winches, capstans, hydraulic cylinders, etc. Contact your Thrustmaster representative or our applications engineering department in Houston.

Proportional Control Means Quick and Efficient Thrust Response

A drop-in style bridge remote control panel comes with a proportional joystick for infinite thrust control in both port and starboard directions. Prime mover controls and dynamic positioning interface can be included on the thruster panel. Additional bridge wing stations or other controls are also available.

Specifications

Technical data are listed below for thrusters with tunnel diameters of 16-inch (406mm), 24-inch (610mm), 30-inch (762mm), and 36-inch (914mm).  For larger tunnel diameters, please contact Thrustmaster’s Sales Department.

Thrustmaster
Power
Thrust Hydraulic
Power Required
Tunnel
Size
Model # HP KW Lbf KN USGPM PSI LTR/Min. Bar

16 inch
(406 mm)
16TT30 33 25 600 2.7 32 1750 120 120
16TT40 43 32 800 3.6 35 2100 130 145
16TT50L 52 39 1000 4.5 48 1850 180 130
16TT50H 55 41 1000 4.5 38 2500 145 170
16TT60L 62 46 1200 5.3 50 2100 190 145
16TT60H 65 49 1200 5.3 40 2800 150 195
16TT70L 72 54 1400 6.2 60 2050 230 140
16TT70H 74 55 1400 6.2 52 2450 200 170
Thrustmaster
Power
Thrust Hydraulic
Power Required
Tunnel
Size
Model # HP KW Lbf KN USGPM PSI LTR/Min. Bar

24 inch
 (610 mm)
24TT60L 61 46 1250 5.6 55 1900 210 130
24TT60H 60 45 1250 5.6 47 2200 180 150
24TT70L 70 52 1500 6.7 57 2100 215 145
24TT70H 71 53 1500 6.7 50 2450 190 170
24TT80L 82 61 1700 7.6 60 2350 230 160
24TT80H 80 60 1700 7.6 52 2650 200 180
24TT90L 90 67 1900 8.5 62 2500 235 170
24TT90H 91 68 1900 8.5 54 2900 205 200
24TT100 101 75 2150 9.6 64 2700 240 185
24TT110 112 84 2350 10.5 66 2900 250 200
Thrustmaster
Power
Thrust Hydraulic
Power Required
Tunnel
Size
Model # HP KW Lbf KN USGPM PSI LTR/Min. Bar

30 inch
(762 mm)
30TT100L 100 75 2200 9.8 69 2500 260 170
30TT100H 98 73 2200 9.8 56 3000 210 205
30TT125L 125 93 2600 11.6 92 2330 350 160
30TT125H 127 95 2600 11.6 73 3000 275 205
30TT150L 152 113 3000 13.4 116 2250 440 155
30TT150H 150 112 3000 13.4 95 2700 360 185
30TT175L 177 132 3400 15.1 119 2550 450 175
30TT175H 177 132 3400 15.1 98 3100 370 210
30TT200 203 151 3800 16.9 120 2900 454 200
Thrustmaster
Power
Thrust Hydraulic
Power Required
Tunnel
Size
Model # HP KW Lbf KN USGPM PSI LTR/Min. Bar

36 inch
(914 mm)
36TT150L 149 111 3200 14.3 109 2350 410 160
36TT150H 149 111 3200 14.3 85 3000 320 205
36TT175L 177 132 3750 16.7 132 2300 500 160
36TT175H 174 130 3750 16.7 115 2600 435 180
36TT200L 201 150 4300 19.2 138 2500 520 170
36TT200H 210 157 4300 19.2 120 3000 454 205
36TT225L 225 168 4750 21.2 143 2700 540 185
36TT225M 226 169 4750 21.2 125 3100 475 210
36TT250L 251 187 5250 23.4 148 2900 560 200
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