New Spanish Sub is Too Big to Berth at Home Port

Ceremony marking the installation of S-81's electric motor, one year before the discovery of the buoyancy problem (Navantia, 2012)

By The Maritime Executive 07-19-2018 08:50:25

Spain's newest submarine, the S-80 Plus, is too big to fit at its home port. A redesign to correct a buoyancy problem left it 30 feet longer than originally planned - about nine feet too long for the submarine slips at Arsenal de Cartagena, the Spanish Navy's sub base. 

Due to a miscalculation during the design phase - a misplaced decimal point, according to a former defense procurement official - the original S-80 hull form turned out to be too heavy by a margin of about 125 tons. To correct the problem, shipbuilder Navantia added three additional compartments to lengthen the design and increase buoyancy, ensuring that the sub would be able to reliably surface from depth. However, this modification made the four-vessel series larger than the existing slips at Cartagena, and the Spanish government will have to expand them at an expense of approximately $20 million. In response to media reports, Spain's Navy contends that the length of the subs is a non-issue, as it has already planned to upgrade and modernize the docks.

Due to the design changes, the S-80 series is already well over budget: at $4.5 billion for four vessels, the program will ultimately cost nearly twice as much as originally planned. For comparison, competing diesel-electric subs typically cost less than $700 million per unit. 

Spain will also have to pay an additional, unplanned $150 million to prolong the service lives of its Cold War-era S-70 series subs, as the delivery schedule for the new S-80s has been pushed back. The first of the new class, the Isaac Peral, is now expected in 2022, rather than 2015, as was originally projected. The last will not be delivered until 2028.