Where would you find whirlpools?

Whirlpools - occur quite frequently in the narrow sea passages between island groups and mainland shores. They are common in the fiords of Norway the long narrow inlets of sea between high cliffs. What happens is that a rotary flow of sea currents is created by a head on meeting of a rising tidal current with the returning ebb current of the preceding tide. Usually whirlpools are more likely to occur over a deep or depressed area of the sea bed. In some cases particularly between the Sea of Japan and the Philippine Sea the whirlpool becomes so great that the rotary flow changes to a spiralling downward flow into a deep centre. This is capable of sucking under water objects as large as ships.