Article 20's national replacement exceptions

Article 20 created special replacement provisions for the British Hawkins-class cruisers Frobisher and Effingham, the Japanese cruiser Tama, Japanese destroyers, and Japanese submarine tonnage. The Japanese clauses allowed some destroyer and submarine replacement work to be brought forward within the treaty period. Exceptions multiplied as negotiators tried to reconcile inherited ships and national plans with a common limit. Britain had a comparatively clear path toward the many light cruisers it wanted, while Japan's concessions look more strained. The United States had moved from seeking twenty-one heavy cruisers to accepting eighteen plus substantial light-cruiser tonnage, even though it regarded 10,000 tons as the minimum useful Pacific cruiser size. These provisions formed a negotiated ledger of fleet-specific compromises rather than a simple ratio.