When we say "thruster", almost always are referring to Tunnel thruster. That is called the thruster unit, which is a transverse cross-cutting tunnel, or simply, a pipe, below the waterline and extending from side to side, with a propeller inside. Running propeller creates a stream of water, whose pressure and turns the ship in the right direction, or both they say, creates stress. To change direction or using a reverse engine propeller with variable pitch, which can turn the blades. Another option is to use two propellers.
On location thrusters are bow and stern. (Similarly see: Alfred Adler). Depending on how you allocate the drive hydraulic, mechanical and electrical thrusters. Interestingly, the term 'thruster device "is also called electromechanical systems, with the function or type of autopilot autopilot, ensuring the continued direction of the ship, for example, strictly on the wind. Given the fact that the tunnel IP permit control the yaw caused by the wind on the nose of the vessel, to determine the precise meaning of the term is problematic. The basic task of thrusters on board is to increase maneuverability. Anyone who has ever tried to maneuver the yacht complete with rudder, I realized what it means to enjoy the controls. But that disproportionately important thruster – a important element of security in a mooring in a strong wind and current, or in cramped conditions the yacht club. When choosing a steering device, the first stage, you have to determine its type. The presence on board hydraulic tank and pump or main engine with a special PTO strong argument for installing a hydraulic PU.