Complex sentence: Until the 20th century access to Padstow's harbour was via a narrow channel between the Doom Bar and the cliffs at Stepper Point, a difficult passage for sailing ships to navigate especially in north-westerly gales when the steerage wind was cut off by the cliffs.
Split into simpler sentences: Until the 20th century access to Padstow's harbour was via a narrow channel between the Doom Bar and the cliffs at Stepper Point. This was difficult for sailing ships to navigate especially in north-westerly gales when the steerage wind would be cut off by the cliffs.