Twydall Profile

The sloping earthworks employed in the Twydall Profile were intended to be quick and inexpensive to construct and to be effective in the face of the more powerful artillery and high explosive ammunition being introduced at that time.

[1] In the United Kingdom, a huge investment had been made in the previous decades in a considerable number of large fortifications to defend the naval dockyards, collectively known as the Palmerston Forts.

The solution devised and promoted by the forward-thinking military engineer, Lieutenant-Colonel Sir George Sydenham Clarke, was for a smaller, less expensive type of fort or redoubt, which could be manned by infantry and mobile field artillery rather than large guns fixed in deep emplacements.

The shallow ditch was crossed by a drawbridge at the rear; however, neither work had the barracks, fixed artillery emplacements, magazines, or caponiers that might have been expected in a fort of this period.

At the foot of the slope is an unclimbable palisade made of angled steel palings, often referred to as a "Dacoit fence", recommended to be 9 feet 6 inches (2.90 metres) tall.