With the Napoleonic Wars in full swing, British and Scandinavian merchant shipping transiting  the lucrative trade route around Orkney were often attacked by French and American privateers. The Hackness Battery and two Martello Towers were built in 1813–14 to help protect the safe anchorage at nearby Longhope Sound. Their guns were never fired in anger. 

The Martello towers at Hackness and Crockness are two of the three such defences built in Scotland, although more than a 100 were built along the south coast of England. They take their name from Mortella Point, Corsica where in 1794, the circular masonry tower located there withstood an assault by two British warships with a combined firepower of 106 guns.