In the Lecture dated 28 March 1930 for aspirant officers of the Royal Netherlands Navy Reserve in the Dutch East Indies was explained what kind of demands a designer had to deal with to come with a compromised design including as much as possible of the demands still without increasing the displacement. The lecturer mentioned that the main task of a submarine was to nearer the enemy without being sighted and to manoeuvre in such a position that she was able to torpedo her target. Large displacements were a disadvantage and submarines were just successful when they operated in large numbers. Large number of small submarines were to prefer above a few large submarines. The main reason to decide to increase the displacement was heavier military demands.
As example was chosen for the fleet submarine type which had to be able to follow the battle fleet and needed a maximum speed of 21-22 miles. There were 3 types of submarines described of which the displacement (1.500 tons), fuel bunker capacity, range, armament, torpedoes and ammunition was similar.
Type A was fitted out with 2.040 hp diesel engines allowing a maximum speed of 15,3 (surfaced)-10,5 (submerged) knots, a submerged range of 180 nautical miles and a test diving depth of 350 metres.
Type B was fitted out with 3.000 hp diesel engines allowing a maximum speed of 17,2 (surfaced)-10,5 (submerged) knots, a submerged range of 180 nautical miles and a test diving depth of 300 metres.
Type C was fitted out with 5.700 hp diesel engines allowing a maximum speed of 21,1 (surfaced)-8,5 (submerged) knots, a submerged range of 110 nautical miles and a test diving depth of 300 metres.
Main conclusion was that to increase the surfaced speed was the diving depth decreased just like the submerged speed and range. The result was that the weight of the battery could be decreased and the electric motors less powerful.
Source
Archive Dutch Naval Staff (National Archive, The Hague, Netherlands) inv. no. 291. Lecture dated 28 March 1930 for aspirant officers of the Royal Navy Reserve in the Dutch East Indies.
As example was chosen for the fleet submarine type which had to be able to follow the battle fleet and needed a maximum speed of 21-22 miles. There were 3 types of submarines described of which the displacement (1.500 tons), fuel bunker capacity, range, armament, torpedoes and ammunition was similar.
Type A was fitted out with 2.040 hp diesel engines allowing a maximum speed of 15,3 (surfaced)-10,5 (submerged) knots, a submerged range of 180 nautical miles and a test diving depth of 350 metres.
Type B was fitted out with 3.000 hp diesel engines allowing a maximum speed of 17,2 (surfaced)-10,5 (submerged) knots, a submerged range of 180 nautical miles and a test diving depth of 300 metres.
Type C was fitted out with 5.700 hp diesel engines allowing a maximum speed of 21,1 (surfaced)-8,5 (submerged) knots, a submerged range of 110 nautical miles and a test diving depth of 300 metres.
Main conclusion was that to increase the surfaced speed was the diving depth decreased just like the submerged speed and range. The result was that the weight of the battery could be decreased and the electric motors less powerful.
Source
Archive Dutch Naval Staff (National Archive, The Hague, Netherlands) inv. no. 291. Lecture dated 28 March 1930 for aspirant officers of the Royal Navy Reserve in the Dutch East Indies.
