The aircraft-bearing subs were designed to bring the war to the US mainland and strategic choke points such as the Panama Canal by hiding offshore and releasing the single-engine bombers on what would be one-way missions. The tactic Japanese war planners envisioned provided a chilling foretaste of tactics the US and Russian navies would use with their ballistic-missile submarines during and after the cold war.
Indeed, the I-14's larger sibling, the I-400 class subs, could be considered the forerunners of today's ballistic-missile "boomers."
At 400 feet long, the I-400 subs were designed to travel 37,500 miles without refueling – enough range to cruise around the world 1-1/2 times between fill-ups and have enough fuel left for their three aircraft. Intended targets for the subs' bombers included Washington and New York. None of these long-range missions were carried out.
The expedition was conducted using manned submersibles operated by the Hawaii Undersea Research Laboratory, a cooperative venture between NOAA and the University of Hawaii. Partial funding for the effort came from the National Geographic Society's cable TV arm, the National Geographic Channel.
Today's announcement comes four and a half years after the same submersible team spotted the remains of one of the largest subs, the I-401 off the Hawaiian Islands.