British military department responsible for artillery, stores and fortification works which became involved in the Isle of Man after Crown rule was established.

The Board of Ordnance managed guns, ammunition, military stores and engineering works throughout the British state. Its connection with Mann is clearest after Revestment, when responsibility for the Island’s military stores and fortifications passed from the former lordly administration into Crown structures.

Earlier Manx offices had combined several duties which were later separated. Evidence given in 1792 recalled that the Commander of Derby Fort and the Steward of the Garrisons and Demesnes were offices under the Lords of Man. The former command was described as “almost a sinecure”, while the steward dealt with repairs to the Lord’s houses, forts and castles and with ammunition and carriage.

After Revestment those offices ceased in their old form. The same evidence records later employment under the Board of Ordnance as Store Keeper and Overseer of the Works. These posts placed the practical care of military stores and public works within the British ordnance system.

The change reflected the wider administrative consequences of 1765. Castle Rushen, the Island’s forts and military stores were no longer maintained as part of the private establishment of the Lord of Man but were increasingly handled through Crown departments.

The surviving evidence is administrative rather than architectural: it describes offices, responsibilities and expenditure rather than giving a continuous history of individual fortification works.