Japanese small cruiser submarines I-16, I-18, I-20, I-22, I-24, I-46-I-48, I-47 remains

Built in 1940. With a displacement of 2,180 (standard)-2,553 (normal)-3,215 (emergency)-3,215 (submerged) tons and as dimensions 109.3 x 9.1 x 5.34 metres. Riveted double hull of ‘D’-steel. Submergence depth 100 metres. Submergence time 60 seconds. Torpedo tubes 8 torpedo tubes Type 95 forward for which 20 torpedoes were carried (12 reload). Fitted out with 1-2 man submarine aff. Propulsion consisted of 10,000 AH-240 cells-240 volts battery and 2 cycle 12,400 shp engines Range 14,000 nautical miles with a speed of 16 knots. Submerged endurance 20 hours/3 knots. Speed 24 (surfaced)-8,5 (submerged) knots.

I-47

The torpedo rooms were forward located in intersecting circles vertically one above the other one similar to the I-400 class submarines. Framing in the lower torpedo room was inside the inner hull while there was not enough space between the inner and out hulls, The outside frame consisting of small scantlings was supported by inside framing (Z-bar section). The pressure bulkheads consisted of intersecting vertical cylindrical surfaces with vertical stiffeners at the traces and furthermore a substantial horizontal box girder. Stiffeners were welded tot he bulkhead which was on her turn welded to a flange ring riveted to the hull. The I-47 was able to carry six so-called Kaitens on deck 2 fore and 4 aft, entered at sea through hatches at the bottom and pipes to submarines. Forward the pipes lead tot he forward battery compartment hatch trunk between the upper and lower hatches, aft were similar arrangements. In this manner were none additional pressure hull openings required. The main engines were fitted out with 750 hp motor driven scavenger blowers which could be cross connected. The bridge was closed and fitted out at the top of the covered position forward with a heavy gears manually trained binocular periscope turret for and reconnaissance purposes.

Source

U.S. Naval Technical Mission to Japan. Report S-01-1 Characteristics of Japanese naval vessels article 1 submarines. Dated January 1946.