Naval Historywith Dr. Alex

Q&A · 15:51-17:07

How treaty rules enabled heavily armed sloops

The 1936 London treaty category for slow, torpedo-less vessels gave the Royal Navy room to build sloop-derived escorts with substantial four-inch armament.

Bittern Class SloopsBlack Swan Class SloopsEscort DestroyersNaval TreatiesRiver Class FrigatesRoyal NavySecond London Naval Treaty (1936)Sloops
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Question

How could Bittern- and Black Swan-class sloops carry six 4-inch guns if earlier treaty rules appeared to limit their armament?

Short answer

The 1936 Second London Naval Treaty category for ships without torpedoes, no faster than 20 knots, and with no gun over 6.1 inches did not limit the total number of qualifying guns.

Notes

The answer turns on Article 1, Category B, Section 5 of the Second London Naval Treaty rather than the older restriction in the prompt. The category excluded torpedoes, speeds above 20 knots, and guns exceeding 6.1 inches, but placed no ceiling on the number of guns that met those conditions. That wording left room for the Bittern and Black Swan sloops to carry multiple four-inch weapons. The same treaty space helped shape the Hunt-class escort destroyers and the design lineage leading toward River-class frigates.