Place MPM1932 - Capstan Square

A capstan would have been situated on or near this site from the 16th century and was used to raise and hold the chain boom which defended the entrance to Portsmouth Harbour. The chain stretched across the harbour and would have been used to prevent enemy ships from entering.

A capstan existed on or near this site since the 16th century and was used to hold the chain boom which defended the entrance to Portsmouth Harbour in place.

The chain boom operated between the Round Tower and a second tower on the Gosport side of the harbour. In the event of an attack the chain would have been raised and held taught by capstans to prevent enemy vessels from entering the harbour. Two sections of chain (now joined together) are held in the Portsmouth Museum Service collection and are on display at Southsea Castle (ref: 1945/1 and 1963/109). Another section of the boom was uncovered on the beach south of 18 Gun Battery in the 1970s (see MPM1931).

Corney, A, 1973, Fortifications in Old Portsmouth - A Guide (Bibliographic reference). SPM388.