A Sinking Decimal Point Error

It was a beautiful luxury liner and the largest passenger ship ever constructed in Italy.  The SS Principessa Jolanda, named after the daughter of Italy’s monarch, King Victor Emanuel III, slowly inched down the slipway.  Halfway down the rails, the ship began to wobble, hitting the water for the first time at a slight angle.

Instead of righting, the ship heeled to the port, causing the crew to rush into action.  The starboard anchors were dropped and the crew tried desperately to right the vessel.  Within ten minutes, the vessel’s list to port was so bad that water began entering the ship, causing the Principessa to capsize, sinking below the surface of the water within an hour of her launch.

The exact cause of the sinking was never officially determined but was thought to be a combination of a poor launch and the ship’s having too high a center of gravity because her coal bunkers were empty.  A sister ship, the SS Principessa Mafalda, named after Jolanda’s younger sister, was later successfully launched with more ballast and with most of her superstructure left unfinished.

I recently finished a class in economic statistics in which I had to do real math for the first time in decades.  Whether it was because it’s been decades since I did any real math, or because age-related brain rot has set in, I found myself frequently making stupid little math errors on a regular basis.  I would drop a decimal point or suddenly decide that two plus two was occasionally five…. Well, for whatever reason, math is harder than it used to be.  After a little research, however, I take some solace in the fact that such errors are more common than I had thought.  (And they are usually made by people who’ve taken far more math courses than I have!)

Mexico City just completely revamped its metro rail system, but when they tried to run the expensive new trains on the existing track, they discovered that the wheelbase of the new cars was too long to take the curves built into the trail line.  The entire new rolling stock of both engines and cars was simply too long to be used—a total loss.  

In 1998, NASA spent $125 million dollars to launch the Mars Climate Observer which, after 10 months, traveled 461 million miles only to crash onto the surface of the red planet.  It seemed that half the engineers who designed her used the metric system while the other half did not.  It was the first time a spacecraft was lost in translation.  

In 2014, France spent $20 billion on brand new commuter trains that proved to be just a few inches too wide to enter the train stations.  So far, it has only cost about $70 million to shave a few inches off the sides of all the train stations' entrances.

No matter how sophisticated the plans and no matter how many times those plans are checked and rechecked, catastrophic engineering failures continue to occur because of the simplest math errors.  I think the best example is the “new” Spanish submarine design.  

Starting back in the 1990’s, Spain decided to upgrade its fleet of submarines.  For technical advice, the Spaniards turned to that country well known for its naval excellence:  France.  (Well, it could have been worse—they could have turned to a landlocked country like Uganda.  On the other hand, Uganda hasn’t lost as many naval battles as France has.)

France had come up with an improved design for two of its existing classes of submarines:  the S-60 and S-70 classes, which were two reliable lines of diesel-electric submarines.  The new class, the S-80 would be substantially larger and able to remain on patrol longer.  In the end, while France decided not to build the S-80 subs, Spain went ahead and ordered a total of four subs with the final design and construction all to be done in Spain.  Each sub would cost $680 million dollars.

The hope was that the new subs would be the start of a new and improved Spanish Navy, restoring national pride in the country’s navy.  Spain had once boasted of the strongest navy in the world, but that was before the country lost the Great Armada in 1588.  Since then, there had been few high points in Spanish naval history.  (There was, for example, that day in September 1898, when the United States easily sank the entire Spanish navy.)

In 2013, shortly before the launch of the first sub, someone doublechecked the math on the ship’s design and discovered that someone else had misplaced a decimal point so that the new boat was going to be 100 tons too heavy to float!  While an extra 100 tons on a 2000-ton ship doesn’t sound like much, it was more than enough to keep the ships from floating.  All subs are designed to go underwater but the people aboard them really like to have confidence they can also occasionally surface…and this one couldn’t.  

Finally, Spain did what it should have done all along and turned to the real experts for help.  The Electric Boat Company—the people who make American subs—was called in to evaluate the design and to suggest a possible solution.  If the subs were lengthened, it would add buoyancy.  The recommendation was to add 33 feet in the middle of the sub, for a measly $9 million a foot.  Each.  And it would require about a decade to accomplish the design changes to the four subs.  This new, new design would bring the sub up to 81 meters length and 3000 tons in weight.  The computer-generated image at left is what the subs would look like before the extension was added.  If you want to know what the finished sub would look like, it’s basically the same but 11% longer.

The extensions were finally finished in 2018 and Spain proudly took possession of the Isaac Peral.  The design was now 30 years out of date and the final price tag for each boat had ballooned to $1.2 billion—roughly twice the estimated original cost—but the first boat off the line was finally put to sea in 2021.  Happily, the navy discovered the sub could resurface when needed.  

Unfortunately, it was at this point that the Spanish discovered a new problem:  The boats were too long to tie up at their docks at the submarine base in Cartagena, a mistake that inexplicably took the Spanish naval authorities five years to notice.

Today, the harbor is being dredged and the docks extended to accommodate what the Spanish are now calling the “S-80 Plus” submarines.  The project is expected to be finished by 2027 at an undisclosed price.

According to the Spanish authorities, “There had been some deficiencies in the program.”