Virtual rendition of the submarine S-80Plus. Navantia

The problems surrounding the bizarre story of the Spanish Navy’s new submarine, the S-80 Plus, have yet to be completely resolved. First, a design flaw meant that the vessel was so heavy that it could not resurface, forcing engineers at the Navantia shipyard to add 10 meters to its length and increase its displacement of water by 800 tons to improve buoyancy.

Now it turns out that this larger version of the S-80 does not fit inside its naval base in Cartagena, in southeastern Spain. This will force the Defense Ministry to enlarge the docking area at a cost of around €16 million.

The program stumbled in 2013, when a weight imbalance cast doubt on whether the submarine would be able to resurface

The Spanish government is due to approve the new spending ceiling for the sub project, bringing the total tab up to €3.9 billion from an initial budget of €2.1 billion. That means that each of the four submarines will come with a price tag of nearly €1 billion, nearly twice as much as initially expected.

Previous ministry officials never got around to approving the new spending guidelines, which means that the team led by the new minister, Margarita Robles of the Socialist Party, needs to fast-track it if it doesn’t want construction to get placed on hold in the fall.

The program stumbled in 2013, when a 125-ton weight imbalance was detected, casting doubt on whether the submarine would be able to resurface.

The Defense Ministry hired a US consulting firm, Electric Boat, which charged €14 million to confirm what experts had diagnosed: that around 10 meters had to be added to the sub’s original length of 71 meters, and that its displacement of water when surfaced had to be raised to 3,000 tons. The new model was called the S-80 Plus.

But one of the collateral effects is that the vessels no longer fit into the docking area of the Cartagena naval base, which can only accommodate lengths of up to 78 meters. For all four subs to to fit, it will be necessary to enlarge the docks and create added infrastructure.

The nearly €1 billion that the Spanish Navy will pay for each S-80 is nearly twice what Israel has paid for German subs

However, the greatest uncertainty lies in the AIP (air-independent propulsion) system, which will give the subs an autonomy somewhere between conventional and nuclear submarines, and allow them to remain underwater for almost two weeks. To avoid further delays, the AIP system will be integrated into the third submarine, whose delivery is scheduled for March 2026. The first two subs, due in 2022 and 2024, will run on diesel propulsion until they are brought in for maintenance toward the end of the decade and fitted with the new technology.

Industry sources said that the success of the S-80 Plus rests on the performance of this Spanish-made AIP system. If all goes well, the S-80 Plus will be a highly competitive product in the conventional sub market, ahead of the German 214. If things go wrong, it will become a failed project, as nobody will want to purchase such a big and indiscreet submarine.

In any event, the state-owned Navantia will have to drastically reduce their price. The nearly €1 billion that the Spanish Navy will pay for each S-80 is nearly twice what Israel has paid for German subs. The market value for this type of submarine is somewhere between €400 and €600 million.

Experts say that such a complex program as this one entails a lot of uncertainty (the final budget earmarks €100 million for unexpected costs), and that the more units get sold, the more of the initial investment will be recouped. But nobody is taking responsibility for the design flaw that has added nearly €1.8 billion to the final cost.