In fact was this design dealing with sub designs
although using the same hull: namely one with single acting heavy oil engines
and one with double acting gasoline engines. The gasoline fuelled engines supplied
more power but were less economical with fuel consumption.
Dimensions 134’10” (over all) x 14’6 1/8” (maximum
diameter) x 14’11 5/8| (maximum beam)
and a displacement of 284 (light)-340 (total excluded the superstructure)-367
(total submerged) tons. Surface buoyancy 19.5% of surface displacement.
Metacentric height while submerged 14”. Metacentric height light condition 8½”.
Range of positive stability.
Fitted out with a conning tower of non-magnetic metal
accessible from the hull by a watertight hatch. A well equipped navigation
bridge was on top of this tower about 10 feet above the water level.
The heavy oil main engines were of the 4-cylinder
vertical inverted type, with a total horsepower of 550hp the gasoline fuelled
engines of the vertical inverted cylinder double acting four-cycle 6-scylinder
type with a total horsepower of 800hp. Fuel bunker capacity around 2.500 US gallons
when gasoline fuelled, in caste she was heavy oil fuelled were ballast tanks
converted making it possible to double the bunker capacity. Main motors were
2-multipolar direct current motors delivering each 135 (continuously)-260 (for
one hour) hp. Guaranteed surface speed with the main engines heavy oil fuelled was
13 knots. With the bunker capacity was the endurance 125 hours or 1.625 knots.
With a cruising speed of 11 knots was the range 2.400 knots. Guaranteed surface
speed with the main engines gasoline fuelled was 14 knots. With the bunker
capacity was the endurance 50 hours or 700 knots. Guaranteed submerged speed
was maximum 10¾ knots and an endurance of one hour. With a speed of 6 knots was
the range 45 knots. Diving time from light to submerged 5 minutes and from
intermediate to submerged in 3 minutes. The hull proper was constructed of
steel allowing to dive to a depth of 200 feet.
Armament consisted of 4-45cm internal in the bow
fitted torpedo tubes firing torpedoes with a length of 5,2 metres. Each tube
was loaded and in this manner available for immediate response. The torpedoes
were launched by air pressure controlled by the commanding officer or his
substitute located at one of the two withdrawable periscopes. There were at the
same time two tubes opened. When these two torpedoes were fired, could within
seconds the other two tubes be opened. Standard was no storage for spare
torpedoes available.
Source
Archive Kon. Mij. De
Schelde 1875-1960 (Municipality Archive Vlissingen) T 214.802. 
