Could someone explain the purpose of the Ōtori-class? They're too large to be Motor Torpedo boats/PT boats. Too small to fight like proper destroyers. Too slow to catch anything besides a slow battleship. And they don't have depth-charges/sonar like Destroyer Escorts.

PraiseVectron said:

Could someone explain the purpose of the Ōtori-class? They're too large to be Motor Torpedo boats/PT boats. Too small to fight like proper destroyers. Too slow to catch anything besides a slow battleship. And they don't have depth-charges/sonar like Destroyer Escorts.

They were pretty much improved Tomozuru-class Torpedo Boats with strenghtened hulls. They weren't adequate substitutes for escort vessels (Mutsuki-class destroyers included) but since they weren't restricted by the naval disarmament treaties, the Japanese built them anyway in order to diminish the disparity between the IJN and USN.

TL,DR; Loophole abuse.

PraiseVectron said:

Could someone explain the purpose of the Ōtori-class? They're too large to be Motor Torpedo boats/PT boats. Too small to fight like proper destroyers. Too slow to catch anything besides a slow battleship. And they don't have depth-charges/sonar like Destroyer Escorts.

They'd have been classified as Corvettes or gunboats in the allied navies, there displacement was similiar to the widely used Flower class for instance. The USN during the war grouped these ships into the generic 'escort' category which covered a number of classes all of roughly this 750-1000 ton weight. They were patrol and escort craft, not intended for fleet combat and the torpedoes on the Otori were largely vestigial and not carried on later types in favor of much larger depth charge loads (although it had to be said this was a two edge sword, the massive depth charge loads on such tiny ships resulted in a marked tendency for truly spectacular deaths when struck by torpedoes).

The Otori did in fact have both sonar and depth charges during the war, and their speed was more then fast enough to dance around a convoy. They were used mainly as escort vessels and occasionally pressed into service running supplies between various tiny islands as so many other IJN vessels where. Like many of the others though they didn't fair so hot in this role... half the class ended up sunk by submarines without ever really doing any damage back (a similar story prevailed elsewhere US submarines sank many more 'escorts' then escorts ever sank US subs).