Using coast-guard service to preserve destroyer capacity

Could old destroyers be kept through the interwar years by converting them to coast-guard duties?

Yes, if they had credible duties and reduced armament; the real gain would be retained crews, maintenance practice, and a pathway to later replacement ships.

Minelayers and destroyers need a real peacetime function if their machinery and trained crews are to survive. A coast-guard mission could justify their speed and a reduced gun armament while making the vessels visibly useful outside the battle fleet. Regular service would keep engines maintained and crews practised instead of leaving nominal reserve ships to decay. It would also create a pathway for replacement coast-guard construction, carrying small-warship skills and personnel into a later mobilisation.