E.U. - S.V. Anzeiger C.37 Kriegsmarine U-boot 10,5cm Flak L/45, circa 1939

Portable calculator called "E.U. - S.V. - Anzeiger" Mod. "C.37" used for firing calculations with 10.5 cm guns supplied with the "Type IX" U-boats and "Type VII" ocean-going boats and on the destroyers of the Kriegsmarine during World War 2. This extraordinary apparatus, mechanical precursor of modern shooting apparatus, was created by "Dr. Pannke Apparatebau Berlin-Lankwitz", or better known as the person who contributed, through large sums of money, to subsidize the creation of the first "modern" computer occurred thanks to the brilliant intuitions of Konrad Zuse.

This tool necessarily takes into account some fundamental characteristics useful for shooting accuracy, divided and reported against:

- Eigenes Schiff" = Proper Position

- Gegner = Opponent Position

"EU/SV Anzeiger" means EU/SV device where "EU "stands for Entfernungsunterschied (differential distance) i.e. the relative distance between ships and "SV" stands for Seitenverbesserung (dot increase) i.e. the deflection of the aim.

Fundamental, given that the firing with the 10.5cm cannon obviously took place when the U-boat was surfacing, was the accuracy of the calculation for the purposes of sinking or seriously damaging opposing vessels. In fact, it must be taken into account that the U-boats, once identified, had little chance of escaping the attacks of Cruisers, Destroyers, etc. equipped with greater fire capabilities even if, in favor of the U-boats, there were the deadly "torpedoes".

The fundamental data thanks to which the certain and exclusive assignment of this instrument to the U-boats can be established is shown on the front plate of the instrument. In fact, in the nomenclature of German cannons, the first digit indicates the caliber expressed in centimeters (10.5cm). , otherwise, "Ubts+Tbts" (Unterseeboot and Torpedobootzerstörer), indicates the guns for use on Submarines and Destroyers.

Finally, Flak L/45 indicates the length expressed in calibers: in this case, the cannon is 45 times the length of the barrel, and was designed to also perform anti-aircraft fire.

Contrary to what one might think, in fact, the 10.5 cm cannon on the uboats was used very frequently as it allowed, when possible, to save torpedoes which were supplied in a significantly lower number compared to the much fewer 10.5 cm shots" bulky".

The instrument, being portable, had to have compact dimensions, which is why its overall dimensions are limited to 31 cm x 22 cm x 7 cm.