Is there anything on a cruise ship that seems to break more regularly, or with more significant consequence, than the podded propulsion systems that now power a majority of the global fleet?
The latest example is the Carnival Vista, the second-newest ship for Carnival Cruise Line, which is off for a 17-day trip through a repair yard to have all four of the bearings on its two Azipod thrusters replaced.
But maybe you heard it 19 years ago, when Carnival cancelled four summer cruises on the Carnival Paradise when a seal broke, allowing seawater into the pod.
Or maybe you heard it in April, when Royal Caribbean International's Oasis of the Seas had to be taken out of service abruptly and sent to the Grand Bahama Shipyard in Freeport for an Azipod repair.
Azipods, developed by the Swedish electrical conglomerate ABB and the Finnish shipyard Masa Yards in the late 1980s, put the motor that runs the ship's propellers outside the body of a ship in a "gondola" suspended from the back of the ship where the rudder typically sits.
Because they can turn on a 360-degree swivel (Azipod stands for Azimuthing Electric Podded Drive), ships don't need a rudder, and maneuverability is vastly improved over a conventional drive shaft.
It is a neat trick, and competitors developed a version, most notably Rolls-Royce, which called its podded propulsion system Mermaid.
But the problem over the years has been that the bearings don't hold up. In 2010, Royal Caribbean Cruises Ltd. was awarded $65 million in a settlement in a suit against Rolls-Royce, in which it alleged that the Mermaids installed on Celebrity Cruises' Millennium-class ships were flawed.
In a statement announcing the settlement, Dan Hanrahan, then Celebrity's president, said that "guests and travel agents should feel confident in Rolls-Royce's assurances of the reliability of the Mermaid pods."
In 2011 Carnival Corp. was awarded $24 million in a suit against Rolls-Royce for defects in the Mermaids on the Queen Mary 2.
Eventually, ABB developed a design where some of the parts that tended to fail in the Azipods could be replaced by a technician crawling down inside the pod, rather than having to access the pod from outside in a drydock.
Still, as the Carnival Vista shows, problems remain. In a statement, Carnival said is working closely with ABB Group to replace the bearings.
After 30 years, cruise lines put up with reliability issues because in addition to maneuverability, the pods save fuel and reduce pollution. ABB says the Azipods are up to 20% more efficient than traditional propulsion systems.
Cancelling three cruises and taking the Vista out of service for 17 days is expected to cost Carnival at least $49.5 million. Call it the price of innovation.