Eyes of the vortex
The vortex in Hayle harbour only appeared a few times a year.
It was a quirk of Victorian engineering devised to stop the harbour silting up. Water would be stored in a pool at high tide and, once the tide had retreated, released back into the harbour to wash away the sand.
The water would get into the pool through a tunnel beneath a quay. But sometimes the tide would come back in faster than the water could pass through the tunnel. This would create the whirlpool.
Below an image of the eye of hurricane Isabel taken from the ISS.
(Hurricane v. Tornado?)