| In 1937 in Romania decided to construct 3 submarines under a new project which was developed by the German engineers working in the Dutch firm «Ingenieurskantoor voor Scheepsbouw (IvS) in the Hague. For a basis was taken the German U-boat project type IA (its prototype – Spanish «Е-1» is more true even). Later, the government refused the construction of the third. It was supposed they will be minelayer submines, but the decision on use of one (S-1) as attacking was accepted. Places for mines were now used as additional fuel tanks. Both submarines were assambled in the State Shipyard of Galatzi, Romania. All works were conducted under supervision and by means of experts of German firm " Deschimag " Bremen.