Tom Shugart, a former U.S. submariner and an adjunct senior fellow at the Center for a New American Security think tank, said that an additional burst of speed can help a submarine evade an incoming anti-submarine warfare torpedo. "Being able to quickly come up to high speed may be necessary in order to either move quickly out of a position where the torpedo can lock on and start homing," he said, "or to run far enough and fast enough that the torpedo runs out of fuel before it reaches the submarine."
Experts in the U.S. have suggested extending the life spans of Japanese submarines to 30 years from the current 22 years. That way, Japan could eventually have a 30-boat submarine fleet without having to add new boats.
Read the full story and more from Nikkei Asia.