The remains of a Henrician artillery castle, built in 1543-4 for Henry VIII as part of his coastal defences against the threat of French and Spanish invasion. It was built on the Hamble foreshore to protect the Solent. In 1642 the castle was taken by Parliamentary forces who dismantled it and it was not recommissioned.
The castle was probably a three-tier fort consisting of a high rectangular tower or keep with a lower semi-circular bulwark or gun tower with parapets and a gun platform. It was surrounded by a moat. A survey of 1595 indicated that lighter carriage-mounted ordnance was positioned on the tower and the gun platform had two larger iron culverines.
All that remains of the castle are fragments of masonry and a break-water on the Hamble shore line.