A €2.2 billion ($2.85 billion) contract to construct four S-80 submarines has been sent off-course by the Spanish government after engineers determined that such vessels, as currently designed, probably would sink to the bottom of the ocean from excess weight and other factors.

Already, the country’s defense department has seen €530 million ($686 million) go down the drain on this project.

Engineers at shipbuilder Navantia, contracted by the defense department to build the subs, estimate that the vessels are each 100 tons too heavy. As a result, Navantia estimates the project will be delayed by up to two years.

According to Naval-Technology.com, each S-80 was designed to “carry out naval power projection operations and surveillance activities, and protect and transport both the naval and army forces in littoral waters.” Each sub is 71 meters in length, 7.3 meters in diameter, weighs a total of 2,200 tons and can carry 32 crewmembers.

The S-80 was once billed as the “most modern submarine” in the world. The Spanish navy was planning to take delivery of the first of the four vessels next year. 

The Local, an English-language Spanish newspaper, reported that engineers have proposed two solutions to the weight problem: reduce the volume and weight of the ships, or make them longer in length. (The latter option would be quite costly, as every meter added to the submarine’s length would entail more than €7.5 million in additional expenditures).

Given the already dire financial condition of debt-wracked Spain, the opposition United Left party has demanded an explanation for why so much money was wasted on such a failing program.