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IJN I-7 (J3 Type)

1937 WORLD WAR 2

History

The IJN I-7 and her sister ship, the IJN I-8, were launched on July 3, 1935, and are the largest submarines ever put to sea by the Imperial Japanese. These ships are primarily designed for long-range reconnaissance work, and thus offer good seaworthiness, strong armament and beyond-visual-range capability, supported by a recoverable seaplane.

In fact, these vessels are long-haul craft, capable of staying at sea for 60 days at a time, with an operating range of about 14,000 nautical miles albeit heavily reliant on food and fuel management. The I-7 had a top speed of 23 knots and could dive to a depth of 325 knots, which proved useful in combat situations.

Despite its reconnaissance role, the I-7 is well equipped for surface operations with 6 x 533mm torpedo tubes and a 140mm deck gun. Being able to launch seaplanes for reconnaissance work, the I-7 was also equipped with a crane for self-recovery of the aircraft.

This provides the ship with a good, self-sustaining combat presence that is critical to Japan's ongoing naval operations in the vast Pacific.

The boat is powered by a diesel electric unit driving two axles. The diesel unit provided the necessary propulsion when it came to the surface, while the electric motor provided the boat with the elixir of life when it was submerged.

The boat can normally move forward 16 knots when it comes to the surface, and the top speed drops to 8 knots when it is launched.

Her overall silhouette was traditional for the time, with a tapered bow and stern. The sails are managed amidships as usual and are fitted with periscopes, antennae and communications. Twin screws are installed in the stern on both sides of the hull. Paddles at the stern end allow turns.

In the bow are the diving aircraft and six torpedo tubes. Deck guns were placed in front of the sails. Their entire crew is 100 people.

I-7's ocean-going career ended on June 22, 1943, when it was attacked and pursued by US Navy destroyer USS Monaghan (DD-354), I-7 landed on a rock bed and was abandoned in the Aleutian Islands nearby crew. Her sister, IJN I-8, was in slightly better condition, but was also sunk by U.S. warships while landing on Okinawa.