The Ronis was a French-built Latvian submarine of 390 tons displacement launched in 1926. The Ronis was powered by two sets of Suizer diesel engines providing a top speed of 14 knots surfaced and 9 knots submerged. She was armed with one 3 inch un; two machine-guns and six 17.7 inch torpedo tubes, two fixed in the bow and the other four in revolvin...