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Bearing failures continue to plague the pod drive systems fitted to many new high-end cruise ships, years after the technology was introduced and long after the bearing failure problem had supposedly been solved.
The latest to be affected, even before it entered service, is The Pride of Hawaii, built by Meyer Werft for Norwegian Cruise Line America (NCL) at its facility in Bremerhaven.
Pride of Hawaii is a 93,500 ton ship equipped with a pair of 20,000kW ABB diesel-electric Azipod pod drive units.
At 965 feet and USD $500+ million, NCL claims Pride of Hawaii is the largest and most costly U.S.-flagged liner ever built. It will carry as many as 2,700 passengers and over 1,100 crew. More than 10 restaurants and 13 bars and lounges are on board.
Launched in the North Sea for pre-delivery trials in mid-March, it was quickly back in dry dock at Blohn+Voss in Hamburg, suffering a bearing failure in one of the pod drives.
At the time, Meyer Werft would only comment that, "we found some filings where they do not belong." And that it changed the bearings, "as a measure of precaution."
However, after replacing the first bearing, follow-up oil analysis showed the need to replace all the key drive bearings in both azipods, necessitating a return trip to Bremerhaven, where it was once again put in dry dock for repair. The trip to Bremerhaven was scheduled -- to clean and detail the ship prior to customer delivery -- but the need to do it in dry dock while the Azipods are repaired was not.
So after less than two weeks in the water, Pride of Hawaii had already experienced two major unscheduled and expensive dry dock visits for replacing the drive bearings -- one set twice -- under its belt. Delivery to NCL was also delayed, triggering penalties under the build contract.
Meyer Werft said: "The delivery was postponed, because the yard changed the bearings of the pod propulsion system as a measure of precaution in order to avoid damage to the system."
Meyer Werft did indicate it would be negotiating with ABB and the bearing manufacturer regarding the costs for the two unscheduled dry docks, repairs, late delivery penalties from NCL America, and other expenses.
Even so, the company continues to support the drive system choice, and eventually delivered the liner to NCL in Eemshaven. The ship will move on to NCL in Baltimore for U.S. inspection and crew training, and is set to be christened in Los Angeles in two weeks.
Government largesse is largely responsible for the ship's existence. Pride of Hawaii is the third U.S.-flagged cruise liner NCL America has put in the water under a provision buried in the Omnibus Appropriations Act for Fiscal Year 2003, the so-called "Hawaii Cruise Ship Initiative" -- promoting sea cruises to and amongst the Hawaiian islands. Pride of Aloha and Pride of America are the other two ships. Unsurprisingly, the legislation was sponsored by Hawaii's Senator Inouye. He will also give a speech at the ship's christening ceremony.
NCL has two other liners under construction by Meyer Werft, Norwegian Pearl and Norwegian Gem. They are scheduled for delivery by early 2007 and mid-2007, respectively.
ABB's Azipods, and their competitor Rolls-Royce / Alstom Mermaid pod propulsion systems, have been plagued by continued -- and hugely expensive -- drive bearing failures.
Several cruise-loving engineers have noted to eBearing that Azipod and Mermaid pod propulsion units seem to be experiencing bearing failures in regular cycles; cycles which seem to be dependent upon the average speed in the water and operating time spent in rougher, open waters.
The other major user of pod drive systems, Celebrity Cruise Lines' Millennium class ships -- Summit, Infinity, Constellation, and Millennium -- have all experienced multiple drive bearing failures, costing the line approximately $100 million per year in repairs, lost revenue and restitution.
One particularly bad month between March and April 2002 saw four cruise liners taken out of service for emergency pod drive bearing replacement and another's delivery delayed when bearings failed on a shakedown trip. Celebrity has been particularly hard-hit as all of its new ships were ordered with pod drive units. In 2003, Celebrity filed a $300 million suit against Rolls-Royce / Alstom, claiming its Mermaid pod drive units are fundamentally flawed and that repair attempts were, "nothing more than an elaborate charade to cover up the truth."
NCL, in fact, currently has two liners out of service due to drive bearing failures. The Norwegian Star, operating in Mexico, canceled cruises and is in dry dock for an Azipod drive bearing replacement. Star experienced a similar pod drive bearing failure in 2004, which also resulted in its being out of service for a period of time. This week, NCL announced its Pride of Aloha (formerly Norwegian Sky) -- sister ship to Pride of Hawaii -- has cancelled cruises and will be out of service until May 26 while the starboard side propeller shaft bearings are replaced.
The actual cost of a pod bearing failure -- taking a liner out of service, canceling reservations, sailing to dry dock, repairs, inspection and putting a ship back into service -- is extremely high. In litigation, Celebrity has claimed $10 million to $14 million for each bearing failure.
But just how high is not normally not disclosed, since the figure is often a point of litigation. However, NCL's 2005 annual report provides a window into at least a portion of their costs. For example, the Star's 2004 bearing failure forced unapproved itinerary changes, triggering $4.3 million in U.S. Customs fines alone.
| Product Model | Inside Diameter | Outside Diameter | Thickness |
| GRAE12NPPB bearing | 12 | 40 | 19 |
| ZKLDF460 bearing | 460 | 600 | 70 |