Which accident had the greatest effect on the Royal Navy?
Short answerThe loss of HMS Thetis, a T-class submarine, is identified because it led the Royal Navy to undertake a major study.
NotesThe loss of HMS Thetis, a T-class submarine, is identified as the accident with the greatest effect on the Royal Navy among those discussed. Her sinking prompted the service to undertake a major study of what had happened. The exchange does not identify the resulting reforms, so the supported conclusion is limited to the scale of the investigation.