The D1 was on the stocks at cartagena when the Spanish Civil War broke out, and was launched after the end of the war with her two sisters D2 and D3. The D-class had a surface displacements of 1,050 tons and 1,375 tons submerged. Each had a surface radius of 9,000 miles and a compliment of 13 men. These submarines were armed with one 4.7in gun, four 37mm AA guns and six 21in torpedo-tubes (four in the bow and two at the stern). Their dimensions were 275.5' x 21.75' x 13'. SG857f