The Royal Navy placed less emphasis on snorkels because its expected operating environment reduced their urgency. Aircraft overhead in the Atlantic were often Allied, while the Pacific offered vast spaces in which a boat might avoid detection. Japanese air-based anti-submarine capability was strong in some units but inconsistent overall. The equipment priority therefore followed the threat environment British submarines expected to face.
Notable Point · 9:46-11:06
Why the Royal Navy placed less emphasis on snorkels
British snorkel priorities reflected an operating environment in which much Atlantic air cover was friendly and Japanese airborne ASW was uneven across the Pacific.