Article 8 of the first London Naval Treaty allowed anti-submarine sloops outside the main restrictions. Britain included the provision but, in this assessment, built fewer than it could have. Japan also recognised the opportunity for escorts below the destroyer category. British sloop requirements helped shape corvettes and later frigates. Black Swan-class sloops supplied a model for the capability sought, while the inability of some civilian yards to handle turbines encouraged a design that more yards could build. Kaibōkan fit within this sloop lineage.
Chapter · 1:53-3:10
Article 8 and the sloop origins of escort design
Article 8 allowed small escorts outside the main treaty restrictions, while British sloop development shows how shipyard capabilities shaped later corvettes and frigates.