Maritime Technology 3 Essay Example | Topics and Well Written Essays - 1500 words

Maritime Technology 3 - Essay Example This propeller shaft which was geared to the main engine shaft subsequently rotated causing the propeller blades to swirl in a circular fashion. The momentum created by this swirling of water towards the rear end of the ship generated a forward thrust helping the ship to forge ahead. This water thrust at the rear end of the ship was made to flow across a rudder plate kept a certain angle; the angle fixed from atop the bridge by the ships navigator. This thrust achieved was at a particular angle thus helping the ship move ahead in the required direction. (Mc George H.D, 1995) Most of the marine ships use diesel engines with low power to weight ratio. Hence the power generation is intermittent; the flywheel attached to the propeller shaft ensuring uniform rpm. Another area of great concern for conventional propellers is the challenge to overcome cavitation. The presence of cavitation limits the ship speed to 35 knots. Increasing the speed of the ship creates low pressure areas around t he propeller leading to the creation of small bubbles around the propeller. ... The rotation of these blades arranged in pusher or tandem configuration generates the required momentum. The steering on the other hand is achieved by rotating the pod by means of slewing gears that are attached to the hull. Rotation of the pod deflects the flow of water to a new direction thus achieving change in direction. (Beijerinck H.C.W & Terwisga T.J.C, 2006) Since the pod can be rotated about its mounted axis, it achieves thrust capabilities in any direction. This therefore facilitates the forward motion, reverse motion and the rotation of the vessel about a small turning radius with the same efficiency. A propulsion pod consists of Fix pitch propeller, Electric AC synchronous motor, Exciter, Propeller shaft, Propeller shaft thrust and support bearings, propeller brake, Propeller shaft seals, Bilge pumps and the control equipment on the inside. The electric motor that is used in pod is stimulated by a frequency converter which is capable of developing full torque in either di rection across the entire speed range. (Azipod Propulsion, 2002) Source: ABB, Viewed on 10th March 2011 This facilitates in fixing the speed of the propeller for different liquid hydrodynamics and therefore achieving optimum propelling efficiency. The outside part consists of the Steering system, lubricating oil equipment and the ventilation unit. The first series of propulsion pods were equipped on M/V ‘Seili by ABB in 1990. (Azipod Propulsion, 2002) Advantages Podded Propellers offer the following advantages over the conventional Propellers. 1. The degree of automation achieved is higher and chances of mechanical upsets are reduced due the system employing electrical energy. 2. The