The Royal Navy Gunbrig HMS Urgent is one of only two ships known to have been built by John Bass the Lympstone shipbuilder (the other being the Royal Navy frigate HMS Cyane).
Trewman's Exeter Flying Post dated 6 December 1804 reported a sailing from Exmouth: "for Plymouth, the Rapid, Collins, and Urgent. Patterson, being two remarkably fine-looking brigs, built at this harbour, one at Mr Bass's yard Lympstone...".
There is very little information about the Urgent available on the WWW. 
According to Wikipedia's "List of Gun Brigs of the Royal Navy" at http://en.wikipedia.org/wiki/List_of_gun-brigs_of_the_Royal_Navy
the Urgent was one of a batch of fifteen "Archer" design gun-brigs ordered in June 1804, built by John Bass at Lympstone, and launched 2 November 1804.
It seems to have had a fairly uneventful career: the only action being the protection of British Forces in an attack on Copenhagen in August 1807. The Urgent was sold out of the Royal Navy in 1816, presumably after the French threat had diminished with the end of the Napoleonic War.
Obadiah Ayles of Topsham fared a little better when these orders were placed : receiving an order for one gun-brig of the same design, called Piercer, 9 January 1804, which was launched 29 July 1804, and two of "Confounder" design 20 November 1804, launched late the following year.