 A blockhouse was added in 1794, with further rebuilding in 1799; magazines from both of these rebuildings remain.Fort Sewall was also rebuilt in 1809 with 8 guns as part of the Second System (1807 to 1820).The secretary of war's report on fortifications dated December 1811 describes the fort as "an enclosed work of masonry and sods, mounting eight heavy cannon, covered by a blockhouse...".