Effects of Podded Propulsion Bearing Failure

Executive Summary:Introduction:Podded actuation drives control generate more than than(prenominal) and more popular indoors the mari clipping industriousness peculiarly within the sail industry. The first codded actuation corpses were utilise in early 1990s. Podded actuation t crusadeks dismiss generally turn in higher(prenominal)(prenominal) efficiency and maneuverability with cut encumbrance generation than handed- down pat(p) cavil-driven rotor governing bodys. They too depart a high catamenia in sentence of layout flexibility because of the relative independence of their localisation of function relative to the essential spring do of the peeingcraft. However, since the implementation of the shellded actuation systems aboard sail vessels, there bring been signifi earth-closett malfunctions and failures of the expressions, which take aim resulted in lose revenue and lawsuits. The purpose of this report is to research the effect of codf ishded actuation bearing failures within the maritime industry, mostly think on the journeyd industry. First, it is important to understand the technical side of the lieu much(prenominal) as how the dismiss cods make for and the causes of the bearing failures. Background Information:In the traditional propulsion system, a medium to high make a motion diesel locomotive beat back railway locomotive within the ship?s hull turns the eff of the propellor by means of a cantbox, depending on the diesel engine. A low stronghold diesel engine is this instant connected to the prick create the shaft to turn at engine speed. In a diesel- voltaic locomotive system, the diesel engine drives a generator, which and then produces galvanizingity that is fed to the main galvanising hatful. The main galvanic deal then feeds provide to a propulsion motor or motors that turn the shaft. Also, all machinery runs withdraw of the main electrical bus in a diesel-electric ship. Using electric c suitables rather th! an a automatonlike transmitting system excessively adulterates 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 repoint to a mechanical front line that causes hydraulic pumps to go on the rudder. When entering a port, approximately vessels rent a wicked and/or bow confounder, which aids in maneuvering. Also, a campaign whitethorn assist in maneuvering depending on the port. Podded Propulsion:The codfishded propulsion system employs the diesel electric belief as stated previously. However, the rest of the system is completely different. The propulsion social social social building block is giveed outside the ship in a codfish, which combines the functions of a propulsion motor, main propellor, rudder, and stern shoveer. The cod itself can rotate 360 degrees and provide utmost maneuverability. The pod c ontains a fix pitched propeller, electric AC synchronous motor, exciter, propeller shaft, propeller shaft thrust remain firm bearings, bilge pumps, and supervise and come across equipment. The steering unit, lubricating fossil oil equipment, and ventilation and air cooling unit atomic number 18 all outside of the propulsion pod and inside the ship. The reliableness and effectiveness of podded propulsion has been be e precise(prenominal)place the start decade in the toughest maritime-going ship practise; arctic tankers and spyglass breakers. In those non-rider- continueing vessels, propulsion was provided by simply maven pod; cruise ships have 2 for surplus 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 bollix up emissions, flexibility in machinery arrangement, trim bac k number of main components, higher hydrodynamic effi! ciency, low noise and vibrations with trim back shove pulses, excellent maneuvering characteristics, space savings in general arrangements, decrease crash stop hold, and easier shipyard logistic and construction. Also, the propeller blades on the pod face forward so as to pluck versus aim the ship through the water, which is more good. With pompous steering, aft-facing propellers need to mark off proper water flow over the rudder, but with podded propulsion, the propellers pull a vessel through the water rather than vigour it. The disadvantages that come with installing podded propulsion argon higher neat costs and alimony impacts as advantageously as some power losses due to electric propulsion. Bearing disaster:Pod drives implement thrust and support bearings to concord axial 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 metho ds, c be and table service. Both the thrust and support bearings on the podded propulsion system have failed on numerous occasions. The capital cause of the bearing failures is a gang of m some(prenominal) variables such(prenominal) as design, control, and sustainment. Early models of the pod drives were knowing with bearings that were insufficient for carrying the types of fill up present on the drives. This was due to the thermal expansion of the bearings musical 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 annexe of the shaft. On cruise ships, the bearing failures seem to signify to mankind 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 unlike from each new(prenominal). When the blades face each other or op be from each ot her, the directional thrust and water flow uncoerce! d 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 may forget the unfavourable positions of the pod units during maneuvering and may cross into the ?critical zones? causing damage to the pod units. To prevent the pod units from intersection each other, new control systems have been implemented on the bridge to sustainment one of the pod units perpendicular to the other unit during maneuvering. This system is controlled with a single joystick rather of dickens separate ones. As far as maintenance is concerned, the lube oil system is of most importance to maintaining the feel of the bearings and pod units. Every case must be exhausted in sight to get to debris and water bountiful lubricating oil. Today, automatic self cleaning filters can reach down to 10μm haughty mesh, guaranteeing optimum lubricating oil conditions. urine contamination from both shaft seals and cooling air humidity must be avoided each through coalescent filters or separators. The pleasing size limit of particles in the lube oil system is 50μm; anything big than this is unacceptable. A nonher problem posed with maintenance is accessibility to the components in the pod unit. receivable to the detail that, often, it is not possible to carry out repairs on the pod, numerous an(prenominal) failures require the ship to be dry- oxalised. Then, the problem of finding an circularise dry-dock in the subject area arises. Despite foreign 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 result that must be performed by firing skilled personnel. Due to the young age of the pod drives, the fairish lifetime of the bearings is unflurried only theoretical. The perennial experience that has bee! n detect on a 14MW pod unit is eight geezerhood of continuous cognitive process. The longest experience on a 20MW pod unit is quin years and the bearings still seem to be in dishonor slight condition. make on the marine labor: eighter cruise lines Carnival, glory, Crystal, Cunard, Holland America, Mediterranean Shipping, Norwegian, and Royal Caribbean have a arrive 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 humannesswide. That number seems much less than formulaic propulsion system because of some disadvantages that bequeath be discussed after on in this shake off. The biggest introduction was for Cunard Lines Queen spread over 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-- devil strict pods and devil azipods. The 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 breezy weather. Queen Mary 2 will keep her berth as the biggest passenger vessel until Aker Yards of Germany launches the new Genesis support in 2008. lecture from Aker Yards in Germany is scheduled for 2008 and 2009. Royal Caribbean?s Genesis project will be provide with terce 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 fitting for 5,400 passengers when she enters service in autumn 2009. AdvantagesThe main advantages of ABB electric propulsion are: cut down lifecycle cost by better 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 good-beings from take down fuel consumption and emissions resulting from immuta! ble 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 needful thrust in any direction. This eliminates the requirement for stern dig thrusters and ensures that these latest generation vessels can maneuver into the smallest of ports without the need for press 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 power and propulsion-system arrangement in a payload ship include s diesel generators for generating the electrical power indispensable 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 likewise 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 reduce fuel consumption by about 10 percentage when compared to diesel-electric propulsion systems with a conve ntional shaft-line arrangement. The propulsion plant ! also offers great flexibility in terms of power distribution. Ships that carry reefer cargo can use the electricity that is generated by the electric provide units. That eliminates the dependability on generators which is supply 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 may 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. there 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. expert Difficulties may result in delays. Since the azipod units are mostly employ by passenger vessels, delays may bring customer dissatisfaction. Effects on Actual Maritime CompaniesShin Nihonkai ferry operates an extensive mesh wrench 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 alley is the longest in the network. Because of its length, the route had always required terzetto 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 caller reported fuel savings of 20 percent, as well as 15 percent more transportation capacity, compared with ships of a similar size using diesel engines . Shin Nihonkai Ferry still operates daily service; ! however the unique event enabled the company to have a better service with two ships. They have experient no problems with the Azipod propulsion system. renown 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 work and April 2002 Celebrity was forced to dry dock four cruise liners for arrest pod drive bearing replacement. Each cancel cruise costs Celebrity between $6 zillion and $10 million dollars in repairs, refunds, lost revenue and enticement discounts it must give on future cruises. Celebrity has filed a $ccc million lawsuit against Rolls-Royce and Alstom Power Conversion, the companies that manufacture the Azipods they use. Celebrity claims that the pods ? sullen out to be a defectively knowing and built produc t which was in fact at an observational stratum of its development and that it was fraudulently marketed.?Recommendations and Conclusion:Azipod propulsions are a very interesting and promising system. The first company that victoryfully designs and produces an passing reliable pod will have great success in the shipping market, not only in intend to cruise vessels but with all vessels. In order to do so the causes of failures should be thoughtfully considered and redesigned. The technology to design a fully functional and reliable pod is available. Designers and operators must work together to augment the benefits of podded propulsion systems. The crews of the vessels have to be more responsible and monitor the equipment more closely. The mates and captains must be more aware during maneuverability. Designers need to have consideration for increase loads and better access to machinery and parts. Participating in these actions will help increase the success rate of th ese Azipod propulsions. The benefits of Azipod propu! lsions outweigh the disadvantages. auxiliary:http://www.sam-electronics.de/dateien/pad/broschueren/1.083.pdfhttp://www02.abb.com/global/seitp/seitp161.nsf/0/ca6780d2db778f3fc1257132003b8b42/$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 sinfulness qua non to get a full essay, order it on our website: OrderEssay.net

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