An early snorkel accelerates the First World War ASW cycle

Could Germany have blockaded Britain if it possessed snorkels in 1914?

Not immediately; too few submarines were available, and British intelligence and ASW development would likely produce countermeasures before the fleet grew.

A snorkel would not enable an immediate 1914 blockade because Germany lacked enough submarines. As numbers grew, British intelligence penetration would make the technology harder to conceal and encourage counters such as heavier depth-charge patterns and purpose-built anti-submarine sloops. The mine-heavy character of First World War submarine operations also limits how directly a later snorkel advantage can be projected backward.