[Onkel Neal]

https://nationalinterest.org/blog/bu...vy-needs-31827

Among the more-than-ample reasons for acquiring a flotilla of diesel-electric submarines for the U.S. Navy: SSKs could help deter war by demonstrating American resiliency should war come in the Western Pacific. Deterrence comes from capability and visible resolve to use it. And from staying power. Foes blanch at starting a fight if they fear they can do little to blunt an antagonist’s warmaking capability. In short, resilient contestants deter. And should war come anyway, an artfully employed diesel contingent could help the United States and its allies—principally Japan—prevail in that war.

An allied sub squadron wouldn’t need SSNs with breakneck speed and unlimited underwater endurance to defend a static island perimeter. SSNs excel at open-ocean combat, but they represent excess capacity and expense—and thus waste—for sentry duty. A U.S.-Japanese squadron would need subs to man the barricade in concert with surface craft, missile-armed troops on the islands, aircraft roving overhead, and well-placed minefields. Picket subs thus need to hover silently and stealthily along the island chain, awaiting their chance to strike.

Diesels can do that. The alliance needs enough sentries to keep up a constant rotation, assuring enough subs are always on guard, along with a reserve to shore up the line when vessels are lost in action. A U.S.-Japanese sub fleet would boast enough hulls to keep up a rotation along the Ryukyus. The JMSDF gets by with nineteen boats after a modest buildup, but the leadership wants more. Add a dozen or so American boats to the combined order of battle, and you’d have an undersea fleet able to hold the line with enough units to spare for offensive missions such as raiding shipping within the Yellow or East China Sea or the Sea of Okhotsk.