On 6 May 1920 asked the Chief of the Dutch Naval Staff at The Hague, Netherlands the liaison officers at London, England and Berlin, Germany to supply all available and/or necessary information dealing with minelayer-submarines. The reason for this request was a possible project for such submarines to be used in Dutch territorial waters or in the Dutch East Indies. In the Dutch naval shipbuilding program for 1925 was such a submarine for the Dutch East Indies planned. The Naval Law was however refused by the Parliament. The first minelayer-submarine in the Royal Netherlands Navy was the former German UC 8 of 1915. Interned during the First World War and later bought by the Dutch cabinet and taken into the service as Hr. Ms. M 1. Despite the intention was the first newly built minelayer submarine not earlier realized as in 1936. The O 19 (first to be named K XIX) was laid down on 15 June 1936. The Kon. Mij. De Schelde at Vlissingen, Netherlands designed in 1929-1934 a minelayer submarine but which was never built.
The Dutch liaison officer at Berlin supplied details about the German submarines adding some general information. He wrote that before the First World War Germany did not possessed any minelayer submarine. In the German navy was none place for such a submarine, only for submarines which could cooperate with the Hochseeflotte (the major surface warships). There were still no ideas in merchant trade war using mines in 1911. The 18 type UC 20 mines were stored in six chutes (later types seemed to have 5 according to the liaison officer) and in fact always lying in the water. The disadvantage was that the mines on top sometimes stuck partly above the water out causing a possible corrosion of important components. To prevent this corrosion were the mines to be laid within 5-6 days after leaving the base. When the chutes were filled with the mines, were these to be tightened to prevent a gliding downwards. This sliding was a potential danger when transferring the mines while it was possible that a mine came below the submarine. As a result was already one submarine destroyed. It was also believed that C type submarines at sea also were destroyed by their own mines. Later were the boats fitted out with an additional safety to prevent damage by an own mine losing it anchor. The liaison officer remarked that the chute-system had the advantage of being very simple.
Displacement 410 (surfaced)-600 (submerged) tons. Speed 11,7 (surfaced)-7,1 (submerged) miles. Able to take 18 UC 20 type mines with her. The armament consisted of 1-8,8cm gun and 1 machinegun. For the gun were 120 shells (?) and for the machinegun 1.600 cartridges available. Fitted out with 2-50 cm bow torpedo tubes and 1-50cm stern torpedo tube and took 7 torpedoes with her. Fitted out with 2-300 hp diesels machinery for surface drive and 2-230 electric machinery for submerged drive. Range 6.500 (8.700) miles with a speed of 6 miles. Fuel bunker capacity 41 (+15) tons?. The crew numbered 3 officers and 23 petty officers and sailors.
Source
Archive Dutch Naval Staff 1886-1942 (National Archive, The Hague, Netherlands) inventory 132a.
Note
1. Of the type UC II minelayer-submarines. The magazine Schiffbau dated 23 April 1919 supplied for this type the following details. Displacement 417 (surfaced)-493 (submerged) tons. Dimensions 52,1 x 5,30 x 3,6 metres. Horsepower 2x250 hp surfaced-2x230hp submerged. Speed 11,4 (surfaced)-7,0 (submerged) knots. Oil bunker facility maximum 56 ton. Range 9.000 nautical miles with a speed of 7 knots surfaced and submerged 55 nautical miles with a speed of 4 knots.
