Tremenheere joined the
Royal Marines on 12 January 1779 as a
first lieutenant, during the
American Revolutionary War. He served at sea for the following three years, including fighting at the
Battle of Dogger Bank in 1781. In 1794, still a lieutenant, he commanded a detachment of marines that fought at the
Battle of Martinique and the
Invasion of Guadeloupe; in the latter battle his unit was key in capturing the strongpoint of Fort Fleur d'Épée. He was then promoted to
captain in 1796 and from around 1799 served on board the
ship of the line HMS Sans Pareil. He was made lieutenant-governor of
Curacoa Island, that island having recently been captured by the forces of Vice-Admiral
Lord Hugh Seymour of which Tremenheere was a part of, on 17 October 1800. Tremenheere served as co-governor of the island with the previous Dutch occupant of that position. As neither man was senior to the other there was often great confusion in the giving of orders and in the control of the island. To further difficulties, Seymour quarrelled with the army's Major-General
Sir Thomas Trigge over who Tremenheere owed subordination to, he being an anomalous Royal Marine. Trigge attempted to replace him as lieutenant-governor with Lieutenant-Colonel William Carlyon Hughes, but Tremenheere refused to give up his position to him. Under orders from Seymour he focused his time on the island on attempting to install a sense of Britishness on the foreign population, it being expected that the islands would stay under their control. In 1801 Seymour died, giving the upper hand to Trigge who finally succeeded in installing Hughes and removing Tremenheere in 1802. Tremenheere returned home to England to get married when the
Peace of Amiens began in the same year. When the Peace ended in 1803 he was assigned to serve on the ship of the line
HMS Caesar in the
Channel Fleet. ==Death==