[1] Cathcart joined the Royal Navy in August 1795 as a volunteer aboard Melpomene, a thirty-eight gun, fifth rate vessel originally captured from the French in 1794, being finally decommissioned in 1815.
[7] He is reported to have served with distinction at the raids on Boulogne, a naval action of August, 1801 in which the Royal Navy attempted to destroy components of the French fleet in that port.
[7] In recognition of Cathcart's conspicuous conduct during the attack, Captain Edward T. Parker sent the following despatch to Nelson on 16 August 1801, having been mortally wounded himself in the action and dying from his injuries a short time later, It is at this moment that I feel myself at a loss for words to do justice to the officers and crew of the Medusa who were in the boat with me, and to Lieut.
The barge and cutter being on the outside, sheered off with the tide, but the flat boat, in which I was, hung alongside, and as there was not an officer or man left to govern her, must have fallen into the hands of the enemy, had not Mr. Cathcart taken her in tow, and carried her off.
[8]Cathcart was appointed as post-captain on HMS Clorinde, captured along with the Surveillante, after foundering on rocks while attempting escape from a joint British and Haitian siege of Santo Domingo, under the command of Emmanuel Halgan, in 1803.
The Cathcart genealogical entry for him states that,"This gallant young officer fell a victim to the yellow fever, at Jamaica, when in command of the Clorinde frigate, with the rank of post-captain, 5th June 1804, in his 22d year, unmarried.