Buoy anti-tank obstacle

Buoy is a British type of anti-tank obstacle used to block roads intended to impede enemy movement.

Each buoy was a truncated cone with a rounded bottom which was constructed out of concrete.

The advantage of buoy was that it could be used to block or unblock a road quickly.

Passing a rod or crossbar through a pair of buoys formed a wheeled axle that could easily be rolled into place; when the axle was removed the buoys could be separated and stood up.

Although easily knocked over, the conical shapes could not be rolled very far, they would move unpredictably and out of the field of view of a tank driver, making it difficult to avoid them.