Why could Fairmile boats hold their own despite being technically slower than German S-boats?
Short answerThey were often faster after crew modifications than published figures suggest and could perform better when rough seas troubled the more highly optimized Schnellboot.
NotesThe Schnellboot's excellent reputation can obscure its dependence on favorable operating conditions. Published Fairmile speeds also understated what crews achieved after modifying engines and equipment, with some boats approaching 30 knots rather than the nominal 23. Rough water could narrow the remaining performance gap because the highly optimized German boat did not suit every sea state. A slower-looking craft with good handling and crew-driven improvement could therefore remain tactically competitive. Clean trial figures alone give a poor ranking of coastal-force performance.