Hello to all ; a small contribution .................
Genesis of the oceangoing U boats in the Kriegsmarine (Type IA and Type IX) - the E-1.
Protracted negotiations with Spain during the period 1926-1929 led to the construction (in the Spanish shipyard Echevarrietta and Larrinaga in Cádiz), under the auspices of the IvS in Rotterdam (Ingenieurskantoor voor Scheepsbouw - IvS or InKaVos, Engineers Office for shipbuilding) of a +/- 650 ton submarine based on the experimental UG design of 1918. The project would be implemented with engines and parts directly from Germany for final assembly of the E-1 in Cadiz. The experiences gained with this design would then be used for the construction of the first oceangoing submersibles post-WWI, the U 25 and U 26 (type IA) for the Kriegsmarine.
By 1931 and despite some difficulties the Spanish submarine, built in Cadiz, had been completed. The ship would be studied by German designers as the basis for subsequent designs including both Type IA and the Batiray (UA) type. The team leader was Kaplt. A.D. Bräutigam and among others also were there kplt. (Eng) Papenberg and Oblt. z. S. Rösing (according to the book First U-Boat Flotilla By Lawrence Paterson) and for others, the sea trials were conducted by specialists from the German submarine Branch, including Lothar von Arnauld de la Périere, an ace of the First World War who had led the U 35 and was also on board another famous skipper: Harald Grosse, who with the U 34 sank the Spanish submarine C-3 on December 12, 1936 off the coast of Málaga (as http://torosencadiz.blogspot.com.ar/201 ... rillo.html.)
In the first two pictures (below) we see the striking resemblance between the E-1 and U 25 (Type IA).
Sources: http://www.t2balli.de/index.php/modellb ... -weltkrieg
https://es.wikipedia.org/wiki/Submarino ... %281934%29
MEGA Fotoalbum, Spanien 1931, 640 Fotos Postkarten, Cadiz Tarifa Tetuan UBOOT eBay.htm
Cheers. Raúl M .