Maritime police were called to Northcote Pt in Auckland's Waitemata Harbour when a sail boat broke its mooring at 3.45pm this afternoon.
A police spokesman said the boat had been moored at Shoal Bay.
A motorist on the harbour bridge said the boat's mast could be seen by drivers. The boat had been banging against one of the bridge pylons.
The police towed the boat to Westhaven Marina and returned it to its owner.
