Tunnel Thruster Remote Controls
The bridge panel features Joystick Control and a LCD (Liquid Crystal Display) panel that conforms to a variety of programmed features.
A built-in Electrical Control Unit (ECU) provides proportional thrust control from zero to full rpm in both the port and starboard direction.
The joystick is friction held style. The basic control panel includes brightness and contrast adjustments, emergency stop button, audible alarm buzzer, and alarm indicators.
The LCD also provides visual control transfer protocol between bridge control panels (when using multi-ple remote panels), plus;
- logic for interpreting the VFD status and its control (when using a VFD)
- logic and input/output (I/O) for DP system command and feedback (if DP interface option is included)
- logic for the thruster status and control (digital and analog I/O signaling)
- motor and VFD alarms and fault status information
Thrust control is proportional to the angle of the joystick lever which is friction held with a center detent for neutral position. The digital readout displays alarms and system status and shows directional feed-back in the form of a directional indicator. Panels are drop-in style with positive twist-lock connections in back.
Tips on Thruster Selection
As a rule of thumb, a bow thruster used for docking and undocking should be capable of producing thrust in pounds of force (lbf) equal to twice the lateral cross sectional vessel area below the water in square feet or two to three times the lateral cross sectional area of the superstructure above the water, whichever is greater.
Sizing of tunnel thrusters for slow speed maneuvering and station keeping depends greatly on the vessel operating parameters. Before making your final selection, consult your naval architect or one of Thrustmaster’s application engineers.
When using tunnel thrusters in waters with high current or while the vessel has forward speed, the thruster becomes less effective. At vessel speeds of 3 knots, the tunnel thruster may lose as much as 25 percent of its thrust. At speeds of 7 knots, the thruster may only produce half of its rated thrust. A Thrustmaster retractable azimuthing thruster may be more appropriate for these applications.
Tunnel thrusters need to be placed below the waterline to prevent air ingestion. If the top of the tunnel is too close to the surface of the water, vortexes may develop, resulting in air from the surface being sucked into the tunnel. This causes airlock, substantial reduction in thrust, excessive noise and vibration, and severe shock leading to the thruster. Consider the vessel draft in unloaded vessel condition. If the thruster is to be used out in open seas, consider vessel heave and roll and consider wave action in determining how far below the waterline your thruster needs to be placed to prevent air ingestion. (See also Tips on Thruster Installation)
If space does not allow proper submergence with a single tunnel thruster on a shallow draft vessel, two or more smaller tunnel thrusters, installed side by side, may be used. Multiple Thrustmaster tunnel thrusters can be powered by a single prime mover with a common hydraulic system, making the thrusters act in unison as if they were a single thruster.
