Perla-class submarine

The Perla class was the third sub-class of the Italian 600 Series of coastal submarines, ten boats named after gemstones and built for the Regia Marina between 1935 and 1937. Contracts were shared between Odero Terni Orlando at Muggiano and the Cantieri Riuniti dell'Adriatico yard at Monfalcone, which built the lead boat Perla, launched in May 1936. They were essentially repeats of the Sirena class, with a larger false conning tower, more modern engines, a radio direction finder that could be controlled from inside the boat and new air conditioning, which raised the displacement slightly. They carried six 533 mm torpedo tubes and a 100 mm deck gun and reached about 14 knots on the surface. Only three of the ten survived the Second World War.