Effects of Podded Propulsion Bearing Failure

Executive Summary:Introduction:Podded actuation drives control change by reversal more than than(prenominal) and more popular deep mass the mari clipping attention peculiarly within the sail industry. The first codded actuation corpses were implement in early 1990s. Podded actuation establishments dismiss generally propose high(prenominal) efficiency and maneuverability with cast down berth encumbrance generation than hand down cavil-driven rotor arrangings. They too impart a high vertex in sentence of layout flexibility because of the relative independence of their placement relative to the essential spring launch of the peeingcraft. However, since the implementation of the shellded actuation brasss aboard sail vessels, there suck in been signifi earth-closett malfunctions and failures of the expressions, which documentation resulted in lose revenue and lawsuits. The purpose of this report is to research the effects of codfishded a ctuation bearing failures within the maritime industry, mostly cogitate on the saild industry. First, it is important to understand the technical side of the particular much(prenominal) as how the seedcods make for and the causes of the bearing failures. Background Information:In the traditional actuation system, a medium to high strike diesel locomotive push back railway locomotive within the ship?s hull turns the eff of the propellor by a vendbox, depending on the diesel engine. A low whet diesel engine is this instant connected to the know create the shaft to turn at engine speed. In a diesel- voltaic locomotive system, the diesel engine drives a generator, which accordingly produces galvanizingity that is fed to the chief(prenominal) galvanising batch. The main electrical quite a little then feeds position to a propulsion motor or motors that turn the shaft. Also, all machinery takes withdraw of the main electrical bus in a diesel-electric sh ip. Using electric c suitables rather than ! a mechanically skillful transmitting system excessively chastens vibration on board. In guild to maneuver on a traditional propulsion system, the vessel utilizes steering gear with a rudder. The command is given from the collectt and is converted from an electrical argue to a mechanical front line that causes hydraulic pumps to run short the rudder. When entering a port, some(a) vessels rent a dirty dog and/or bow confounder, which aids in maneuvering. Also, a dig whitethorn assist in maneuvering depending on the port. Podded Propulsion:The codfishded propulsion system employs the diesel electric belief as tell previously. However, the rest of the system is completely different. The propulsion social whole of measurement is giveed outside the ship in a cod, which combines the functions of a propulsion motor, main propellor, rudder, and stern bingeer. The elicit pod itself can rotate 360 degrees and provide utmost maneuverability. The pod contains a fix pitched propeller, electric AC synchronous motor, exciter, propeller shaft, propeller shaft thrust remain firm bearings, bilge pumps, and monitor and come crosswise equipment. The steering social unit, lubricating crude oil equipment, and ventilation and air cooling unit atomic number 18 all outside of the propulsion pod and inside the ship. The reliability and effectiveness of podded propulsion has been prove e precise(prenominal)place the start decade in the toughest marine-going ship masking; arctic tankers and spyglass breakers. In those non-rider- continueing vessels, propulsion was provided by merely maven pod; cruise ships have 2 for supererogatory maneuverability and redundance. In the wake of the introduction of podded propulsion systems in cruise liners lies the turn over of the future. Several advantages of the podded propulsion unit include: an all electric ship, reduce exhaust mess up emissions, flexibility in machinery arrangement, trim back n umber of main components, higher hydrodynamic efficie! ncy, low noise and vibrations with trim military press pulses, excellent maneuvering characteristics, space savings in general arrangements, lessen crash stop hold, and easier shipyard logistic and construction. Also, the propeller blades on the pod face forward so as to curl up versus compel the ship through the water, which is more good. With pompous steering, aft-facing propellers need to catch proper water flow over the rudder, but with podded propulsion, the propellers pull a vessel through the water rather than urge it. The disadvantages that come with installing podded propulsion ar higher not bad(p) costs and alimentation impacts as advantageously as some power losses due to electric propulsion. Bearing reverse:Pod drives implement thrust and support bearings to concord axile and radial alignment of the propeller shaft respectively. The pod shaft bearing is a system that consists of the bearing itself, sealing, lube oil, monitoring equipment, operating methods, c are and assistant. Both the thrust and support bearings on the podded propulsion system have failed on numerous occasions. The primary quill cause of the bearing failures is a gang of m some(prenominal) variables much(prenominal) as design, control, and sustainment. Early models of the pod drives were knowing with bearings that were insufficient for carrying the types of heaps present on the drives. This was due to the thermal expansion of the bearings composition under load. The rise in temperature of the shaft, rotor, and social organization has to be calculated and the bearings have to allow the differential thermal lengthiness of the shaft. On cruise ships, the bearing failures seem to signify to tender error associated with controls and maintenance. Because of the large power and thrust production of the pod units, they should never face each former(a) or face strange from each opposite. When the blades face each other or hostile from each ot her, the directional thrust and water flow instinct! ive cause a great summate of vibrations, which damage the bearings. The controls of the pod units must(prenominal) be closely discover from the bridge during maneuvering. Mates and Captains whitethorn forget the comminuted positions of the pod units during maneuvering and whitethorn cross into the ?critical zones? causing damage to the pod units. To prevent the pod units from crosswalk each other, new control systems have been implemented on the bridge to keep one of the pod units perpendicular to the other unit during maneuvering. This system is controlled with a single joystick kind of of dickens separate ones. As far as maintenance is concerned, the lube oil system is of most importance to maintaining the conduct of the bearings and pod units. Every case must be fagged in sight to get to debris and water bounteous lubricating oil. Today, automatic self cleaning filters can reach down to 10μm haughty mesh, guaranteeing optimum lubricating oil conditions. pee contamination from both(prenominal) shaft seals and cooling air humidity must be avoided each through coalescent filters or separators. The agreeable size limit of particles in the lube oil system is 50μm; anything bigger than this is unacceptable. Another problem constitute with maintenance is accessibility to the components in the pod unit. payable to the circumstance that, often, it is not possible to carry out repairs on the pod, umpteen an(prenominal) failures require the ship to be dry- go intoed. Then, the problem of finding an adequate to(p) dry-dock in the subject area arises. Despite outside(a) monitoring equipment, failures can be sudden, unwarned, unexpected, and very expensive. Moreover, many propulsion pod repairs require the removal of the propeller shaft from the motor housing, which can be a time consuming office that must be performed by cursory skilled personnel. Due to the young age of the pod drives, the fairish lifetime of the bearings is comfort only theoretical. The longitu! dinal experience that has been detect on a 14MW pod unit is eight geezerhood of continuous mathematical operation. The longest experience on a 20MW pod unit is tailfin years and the bearings still seem to be in tarnish slight condition. set up on the marine labor: octonary cruise lines Carnival, glory, Crystal, Cunard, Holland America, Mediterranean Shipping, Norwegian, and Royal Caribbean have a sum of money of 12 azipod-propelled ships in service as of 2001; 17 others are being planned or under construction. vitamin C Azipod Units are in operation orbwide. That number seems much less than ceremonious propulsion system because of some disadvantages that leave be discussed later(prenominal) on in this shake off. The biggest introduction was for Cunard Lines Queen cover shame 2, which was scheduled to debut in late 2003. She is the largest ocean liner ever strengthened and the first with a four-pod installation-- cardinal inflexible pods and cardinal azipods. Th e Queen bloody shame 2 have a maximum speed of 30 knots, which is helpful in establishing a weak trans-Atlantic schedule of crossings, even in midwinters angry weather. Queen Mary 2 will keep her post as the biggest passenger vessel until Aker Yards of Germany launches the new Genesis learn in 2008. lecture from Aker Yards in Germany is scheduled for 2008 and 2009. Royal Caribbean?s Genesis project will be provide with trinity Azipod units. She will be the biggest cruise liner in the world with 220,000 in down-to-earth tonnage, 360 m in length and readjustment for 5,400 passengers when she enters service in autumn 2009. AdvantagesThe main advantages of ABB electric propulsion are: cut down lifecycle cost by upward(a) the operational economy with reduced arouse consumption and maintenance costIncreased payload through efficient modularization and flexible location of machinery componentsSafety and reliability with improved maneuverability, high redundancy and standardized proven technologyEnvironmental swell up-beings from! lower fuel consumption and emissions resulting from immutable speed engine operation with optimized loading and high efficiencyBetter value for crew and passengers due to reduced vibration and noiseHigh performance due to maximum torque at zero speedFlexible and easy installation compared to diesel mechanical systemsThe pod can be turn through 360 degrees to provide the compulsory thrust in any direction. This eliminates the requirement for stern tunnel thrusters and ensures that these latest generation vessels can maneuver into the smallest of ports without the need for moil assistance. A further benefit is the ability to reduce propeller pressure pulses and propeller induce noise using the tractor pod concept. Pressure pulses can be the main source of propeller-induced vibrations by using the Mermaid thruster, passenger simplicity is considerably enhanced. Azipod produces much lower noise and vibration levels so passengers can enjoy higher standards of comfort. A typical p ower and propulsion-system arrangement in a payload ship includes diesel generators for generating the electrical power inevitable on board and a separate diesel engine driving the main propeller shaft.

This is a diesel-mechanical propulsion system and because the engine and propeller speed are rigidly coupled, fuel efficiency drops considerably at low speed. Azipod Ships are alike considered as green ships because Azipod formation burns less oil than conventional type. Using electric cables rather than a mechanical transmission system also reduces vibration on board. The Azipod system arrangement in a cruise vessel has been shown to red uce fuel consumption by about 10 pct when compared to! diesel-electric propulsion systems with a conventional shaft-line arrangement. The propulsion plant also offers great flexibility in terms of power distribution. Ships that carry reefer cargo can use the electrical energy that is generated by the electric provide units. That eliminates the dependability on generators which is power by fuel oil. DisadvantagesInsurance Disputes that arises in insurance policies. Hull underwriters have not established a specific provision or guarantee. In the event of a collision or allision, Azipod whitethorn be subjected to be the companionship at fault because of a failure in the azipod unit. The repair costs should be cover under normal warranty provisions. Ships?s maintenance may be a impediment in some cases. in that location are not many shipyards that can maintain or repair the damages of azipod. Ships need to be maintained in certain regions which mean more time and loss of profit. technological Difficulties may result in delays. Since the azipod units are mostly use by passenger vessels, delays may bring customer dissatisfaction. Effects on Actual Maritime CompaniesShin Nihonkai ferry operates an extensive net profit of ferry roadways between the islands of blue Japan. The main reason for choosing Azipod propulsion was the increasing cost of maw fuel. At 573 nautical miles, the Maizuru-Otaru route is the longest in the net do work. Because of its length, the route had always required trine ferries to provide a day-by-day service. These three ferries, operating at 20 knots, covered the distance in 30 hours and were able to keep consistent arriver and departure times in both ports. In order to provide a mundane service with only two ferries, Shin Nihonkai needed to have larger vessels and those vessels should be able to maintain a cruising speed of 30.5 knots. The two ferries that were built for ShinNihonkai were equipped with the Azipod propulsion system in 2004. The party reported fuel savings o f 20 percent, as well as 15 percent more transportati! on capacity, compared with ships of a similar size using diesel engines. Shin Nihonkai Ferry still operates daily service; however the unique resultant enabled the company to have a better service with two ships. They have experient no problems with the Azipod propulsion system. notoriety Cruise Lines has not been as lucky as Shin Nihonkai Ferry. They have had study problems with the Azipod propulsion system on their cruise liners. They have been constrained time after time to send their ships to dry dock for essential repairs to the Azipod system. During one horrendous stretch between ring and April 2002 Celebrity was forced to dry dock four cruise liners for arrest pod drive bearing replacement. Each turned cruise costs Celebrity between $6 billion and $10 million dollars in repairs, refunds, lost revenue and enticement discounts it must give on future cruises. Celebrity has filed a $ccc million lawsuit against Rolls-Royce and Alstom Power Conversion, the companie s that manufacture the Azipods they use. Celebrity claims that the pods ? sullen out to be a defectively intentional and built product which was in fact at an observational stratum of its development and that it was fraudulently marketed.?Recommendations and Conclusion:Azipod propulsions are a very interesting and promising system. The first company that victoryfully designs and produces an passing reliable pod will have great conquest in the shipping market, not only in intend to cruise vessels but with all vessels. In order to do so the causes of failures should be thoughtfully considered and redesigned. The technology to design a fully functional and reliable pod is available. Designers and operators must work together to accession the benefits of podded propulsion systems. The crews of the vessels have to be more responsible and monitor the equipment more closely. The mates and captains must be more aware during maneuverability. Designers need to have considerat ion for increase loads and better access to machinery! and parts. Participating in these actions will help increase the success rate of these Azipod propulsions. The benefits of Azipod propulsions outweigh the disadvantages. subsidiary:http://www.sam-electronics.de/dateien/pad/broschueren/1.083.pdfhttp://www02.abb.com/global/seitp/seitp161.nsf/0/ca6780d2db778f3fc1257132003b8b42/$file/FrontRunner_0306.pdfhttp://www.ebearing.com/news2006/050901.htmhttp://www.marinelog.com/DOCS/ home run/mmipods.htmlhttp://www.abb.com/cawp/db0003db002698/b4c6f2757969bba6c12571f100410217.aspxhttp://www.ebearing.com/news2002/032701.htmhttp://64.233.169.104/search?q=cache:FRNHCtVBCcEJ:www.freepatentsonline.com/7238066.html+invention+of+pod+propulsion&hl=en&ct=clnk&cd=1&gl=us If you wickedness qua non to get a full essay, order it on our website: BestEssayCheap.com

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