 Decommissioned in 1854 , the castle was first leased , and later bought outright , by the Royal Yacht Squadron to form their new clubhouse . The Squadron then employed the architect Anthony Salvin to rebuild large parts of it between 1856 and 1858 . It became the headquarters for part of the D @-@ Day invasion force during the Second World War , but has otherwise remained in use by the Squadron and is a distinctive landmark in yacht races along the Isle of Wight . 
