Towry was born in March 1767, educated at Eton College and joined the Royal Navy at 13 under the patronage of Lord Longford. He served during the American Revolutionary War aboard HMS "Alexander" and participated in the relief of the Great Siege of Gibraltar in 1782. Following the end of the war he continued in service under the Duke of Clarence and at the outbreak of the French Revolutionary Wars he was attached to the Mediterranean Fleet under the patronage of Lord Hood. He was rapidly promoted and by 1794 was a post captain in command of the small 28-gun frigate HMS "Dido". "Dido" was the only ship of the Mediterranean Fleet to exchange fire with French ships during Martin's cruise of 1794, but was unable to prevent the French escaping into Gourjean Bay.