Great Britain owned Florida at the time because Spain made an unfortunate alliance with France during the French and Indian War (the one during which the Acadians were sent into exile). During the fighting France lost her prized possessions of Havana and Manila to the superior British navy. When the war ended, Spain had to give Florida to Great Britain to get Havana back.
But when the British moved into the fort at Pensacola, they found that there weren't any good maps of the Florida coast, or, for that matter, any of the northern Gulf of Mexico. They picked a cartographer named George Gauld to remedy that situation.
Gauld began mapping the Florida coast in 1764 at Pensacola, studied the Tampa Bay region beginning in 1765, worked in the Mobile area in 1768, and studied Key West and the Caribbean beginning in 1773.
Then, in 1776, with the outbreak of the American Revolution, the mouth of the Mississippi River became very important to the British. The British war planners thought about sailing up the Mississippi into the Illinois country and invading the American colonies from the rear. But they didn't know much about the river's mouth and weren't sure they could get big warships through the shallows at its mouth.
Gauld sailed in May 1777 aboard the survey ship Florida to take a look at the river's entrance. He found 14 feet of water at Southwest Pass then continued to examine the coast "a little to the Westward of the Mississippi," sailing as far west as Timbalier Island in Terrbonne Bay before heading back to British territory for supplies.
He headed west again once he was reprovisioned, sailing into Atchafalaya Bay and at least ten miles up the Atchafalaya River. He noted that the river itself was nice and deep but that "there is such a Ledge of Oyster Banks between it and the Sea that it is hardly possible to find a Channel even for a small Vessel."
He charted Vermilion Bay and mapped Marsh Island, noted an old wreck at the mouth of the Mermentau River, and reached the mouth of the Calcasieu River on July 20.
At the mouth of the Sabine River, near modern Louisiana Point, according to Gauld's journal, "We found the Wreck of a Sloop ... [and] took aboard three men belonging to her, the Captain, Passenger, & all the rest of the People being Dead." He said "savages" had stripped the vessel of its sails and anything else that could be carried away.
According to Gauld the ship had sailed for the Mississippi River from Montego Bay, Jamaica, the previous November but "falling in to the Westward, they bewildered themselves on that desolate Coast & were cast away."
The three survivors took one of the ship's boats and "wandered along the coast for some Months in quest of the Mississippi, but after a fruitless search ... returned to the Wreck for some Provisions, and were just going away again when providentially the Surveying Sloop Florida appeared and relieved them from their distress July 22nd, 1777, after they had been eight Months away from Jamaica."
On the way home, Gauld ran into a Spanish ship and nearly had what he called a "scuffle." He noted that the Spanish governor of New Orleans, "who in several Actions toward the English on the Mississippi seems to have been rash and ill advised" took it upon himself "to send down an Armed Brig with a Large Party of Soldiers on purpose to take or destroy us."
Gauld talked himself out of that one, but what he didn't know was that the rash Spanish governor, Bernardo de Galvez, was about to exhibit even worse behavior.
He and a little army that included Acadians, Attakapas Indians, and a motley assortment of other folks were about to march on Baton Rouge and Mobile in support of the American Revolution, and then to move on to seize Gauld's home port of Pensacola.
You can contact Jim Bradshaw at firstname.lastname@example.org or P.O. Box 1121, Washington LA 70589.