The treaty exemptions that preserved sloops and gunboats

Which navy made the best use of the treaty provisions for 600-ton and other exempt small ships?

The provisions deliberately enabled gunboats and sloops, while the British exploited flexible designed-speed wording to obtain more capable vessels.

The 600-ton exemption was deliberate rather than an accidental loophole. Treaty negotiators protected small gunboats and larger sloops needed for routine imperial and presence duties. The restriction concerned the speed for which a ship was designed, allowing machinery to be officially rated conservatively while offering more power in wartime. The 1939 Sinking incident, in which a sloop kept pace with a Town-class cruiser, illustrates how elastic those paper limits could become in service.