A new submarine commissioned by the Spanish navy at a cost of 2.2 billion euros (£1.9billion) has been discovered to contain a serious design flaw – it is too heavy.
Miscalculations at the engineering stage have been blamed for a two-year delay in delivery of the first of four submarines commissioned from Spain's state-owned shipbuilder Navantia.
Last month it emerged that the Isaac Peral sub – part of the new S-80 series and named in honour of the Spanish man credited by some as the inventor of the underwater vessel – was at least 75 tons overweight, an excess that could compromise its ability to surface after submerging.
Navantia admitted the existence of "deviations related to the balance of weight" in the vessel and estimated it would take up to two years more to correct the problem.
The 233ft vessel may have to be lengthened to compensate for the excess weight, a redesign that comes with an estimated cost of 7.5 million euros per extra metre.
The shipbuilders based in Cartagena, southern Spain, are now seeking "technical experts from abroad" to advise in the redesign of what was billed as the "most modern conventional submarine".