Ontario were blockaded in the mouth of the Niagara River by three larger American vessels. Commander Alexander Dobbs, in command of the British vessels, and his sailors and Royal Marines dragged a gig and five other boats overland from below Niagara Falls and launched a boarding attack on the American schooners off Fort Erie on the night of 12 August. The crews of the schooners spotted and challenged them, but the British replied "Provision boats", and deceived the Americans long enough to bring their boats alongside. They captured and . The crew of escaped by cutting their anchor cables before slipping away, but were accidentally fired upon by US artillery on the shore. The British lost 2 killed and 4 wounded in the engagement, while the Americans had 1 killed and 70 captured, of whom 8 were wounded. This victory raised British morale but Drummond mistakenly believed that it depressed American morale to the same extent. Some American deserters reported this, as well as saying that the defenders numbered only 1,500, when there were 2,200 troops. British assault On 13 August, Drummond opened fire on the fort with two light 24-pounder field guns and four 18-pounder or 24-pounder naval guns. Because the bombardment was fired from too long a range, it was ineffective against the fort's walls. Drummond launched a three-pronged attack on the night of 15/16 August, with each arm of the attack aimed at one of the American batteries. The largest column, of 1,300 soldiers led by Lieutenant Colonel Victor Fischer, would outflank the south end of the defenses at Snake Hill. Another column of 700 soldiers under Colonel Hercules Scott, would attack the Douglass Battery and the north end of the defenses, and sweep into the U.S. camp, meeting Fischer's column in the middle. Finally, a column of 360 soldiers, sailors and marines led by Lieutenant Colonel William Drummond would attack the fort once the other assaults were under way, with the objective of capturing the old British barrack buildings. A reserve of nearly 700 men (the 1st Battalion of the Royal Scots, the Glengarry Light Infantry, the Incorporated Militia of Upper Canada and those soldiers from the Regiment de Watteville who had not volunteered to take part in Fischer's attack on the Snake Hill battery) was left in the siege lines under Lieutenant Colonel Tucker. Colonel Scott and Lieutenant Colonel Drummond were both experienced soldiers and