Capital-ship battles receive far more attention than the sustained combat faced by small escorts in ONS 5, SC 130, and HX 239. ONS 5 became a seven-day battle against roughly 30 U-boats, an action that would likely be far better known had a battleship been at its center. SC 130 and HX 239 were further convoy battles in the same campaign, fought by combinations of frigates, sloops, corvettes, an escort carrier, and aircraft. Their layered defence paired centimetric radar with growing numbers of Hedgehog and Squid mortars and heavy depth-charge loads. River-class frigates represented roughly a fourth or fifth wartime escort iteration, with variants shaped by naval or merchant-yard construction and by British or Canadian production. By 1943, those rapidly evolving surface escorts imposed mounting risks on the Type VIIC U-boats that still formed most of Germany's submarine force. These small ships accumulated extensive campaign service even when popular histories gave them fewer individually named battles.
Chapter · 12:57-15:59
ONS 5, SC 130, HX 239, and layered convoy defence
Three hard-fought convoy battles show how radar, aircraft, escorts, and increasingly numerous anti-submarine weapons combined against U-boats.