The two flue harpoon or two flue iron (which, together with the one flue harpoon

One flue harpoon

The one flue harpoon or one flue iron is a type of harpoon used in whaling after its introduction in the early 19th century when it replaced the two flue harpoon...

, were known as common harpoons) is a type of harpoon

Harpoon

A harpoon is a long spear-like instrument used in fishing to catch fish or large marine mammals such as whales. It accomplishes this task by impaling the target animal, allowing the fishermen to use a rope or chain attached to the butt of the projectile to catch the animal...

 used in whaling

Whaling

Whaling is the hunting of whales mainly for meat and oil. Its earliest forms date to at least 3000 BC. Various coastal communities have long histories of sustenance whaling and harvesting beached whales...

 for at least 1000 years. It appears in works of art dating back to the 14th century.

In the early 19th century the design was modified, and the one flue harpoon

One flue harpoon

The one flue harpoon or one flue iron is a type of harpoon used in whaling after its introduction in the early 19th century when it replaced the two flue harpoon...

was created. By removing half of the point, the chance of the point cutting its way back out of the whale was greatly reduced.