[5] In August 1814, Vice Admiral Alexander Cochrane had convinced the Admiralty that a campaign against New Orleans would weaken American resolve against Canada, and hasten a successful end to the war.

[7] To this end, an expeditionary force of about 8,000 troops under General Edward Pakenham had arrived in the Gulf Coast, to attack New Orleans.

[10] Patterson dispatched Lieutenant Thomas ap Catesby Jones and a small flotilla to wait outside of the Rigolets heading eastward, towards the passes Mariana and Christiana (marked on Lossing's map, close to Cat Island), to watch the movements of the British vessels.

[14] Vice Admiral Sir Alexander Cochrane, British Commander-in-Chief of the North American Station, ordered HMS Seahorse, Armide and Sophie from Pensacola to the anchorage within Ship Island (Mississippi).

[15] This location, known today as Bayou Bienvenue, at the head of the lake, situated 60 miles (97 km) from the troopship anchorage of Cat Island, was to be the disembarkation point for the British soldiers.

On December 12 the squadron arrived at Cat Island, but found the overwhelming strength of the British would have been disadvantageous to the gunboats, so they returned in the direction of the Rigolets, and the fort at Petit Coquilles.

[21] Owing to the strong current, they were only able to get as far as the channel between the mainland and Malheureux Island on December 13 (to the south of the modern day settlement of Ansley, Mississippi).

[22] Jones had been ordered by Patterson to position his gunboats across Pass Christiana, then at the mouth of Lake Borgne, then fall back to the Rigolets to make a stand.

[23][17] At night on December 12, the British rowboats, under Lockyer, set off to enter Lake Borgne, to attack the gunboat squadron.

[13] Jones sighted the British rowboats on December 13 at 10:00am believing them to be disembarking troops, advancing in the direction of Pass Christian and then stopping.

At 2:00pm she had been sent to remove, or failing that to destroy, a stores dump at Bay St. Louis in order to prevent its capture by British forces.

Sea Horse faced a subsequent rowboat attack with four more launches as reinforcements, commanded by Captain Samuel Roberts of HMS Meteor.

'[3] In the face of superior numbers, the Sea Horse was scuttled and the store was set alight, an explosion occurring at 7:30pm with a large fire being visible thereafter.

[25] After rowing for about thirty-six hours,[14] the British approached the five American vessels drawn up in line abreast to block the channel between Malheureux Island and Point Claire on the mainland.

[14] The American sailors killed or wounded a number of the rowboat crews in the process, including most of the men in Lockyer's boat.

Whilst the British outnumbered the American seamen, Roosevelt does note the advantage Jones's flotilla had in defense, being stationary, having some long heavy guns and boarding nettings.

The casualties were from the following vessels: Tonnant, Norge, Bedford, Royal Oak, Ramillies, Armide, Cydnus, Seahorse, Trave, Sophie, Belle Poule, Gorgon, Meteor.

[34][c] As well as the warships providing men for the boats, there were sailors from the troopships Alceste, Belle Poule, Diomede and Gorgon.

The following troopships were nearby, and thus eligible for prize money: Bucephalus, Dictator, Dover, Fox, Hydra and Thames.

After the population of the city learned of the engagement on Lake Borgne, panic overtook some inhabitants of New Orleans; so Andrew Jackson declared martial law on December 15.