Spain's S-81 Isaac Peral Submarine Cost $680 Million To Build... And Can't Float

According to El Pais, the S-81 Isaac Peral -- the first of four state-of-the-art new submarines commissioned for the Spanish Navy -- is 75 to 100 tons overweight.

Among the S-80's celebrated advancement is a diesel-electric propulsion engine that, ironically, promises to be 20% lighter than comparable systems while delivering 50% more power.

If Spain hopes to salvage its submarines, it must either find some weight that can be trimmed from the current design or lengthen the ship to accomodate the excess weight, The Local notes.