An army of 130,000 men, with 400 guns and 20 days' supplies, was to embark from four ports close to Boulogne as a center, and cross the 36 miles of Channel to a favorable stretch of coast between Dover and Hastings, distant from London some 70 miles. The transport flotilla, as finally planned, was to consist of 2000 or more small flat-bottomed sailing vessels with auxiliary oar propulsion-_chaloupes_ and _bateaux canonnieres_, from 60 to 80 feet over all, not over 8 feet in draft, with from two to four guns and a capacity for 100 to 150 men. Large open boats (_peniches_) were also to be used, and all available coast craft for transport of horses and supplies. Shipyards from the Scheldt to the Gironde were soon busy building the special flotilla, and as fast as they were finished they skirted the shores to the points of concentration under protection of coast batteries. Extensive harbor and defense works were undertaken at Boulogne and neighboring ports, and the 120 miles from the Scheldt to the Somme was soon bristling with artillery, in General Marmont's phrase, "a coast of iron and bronze." The impression was spread abroad that the crossing was to be effected by stealth, in calm, fog, or the darkness of a long winter night, without the protection of a fleet. Almost from the first, however, Bonaparte seems to have had no such intention. The armament of the flotilla itself proved of slight value, and he was resolved to take no uncalled-for risks, on an unfamiliar element, with 100,000 men. An essential condition, which greatly complicated the whole undertaking, became the concentration of naval forces in the Channel sufficient to secure temporary control. "Let us be masters of the Strait for 6 hours," Napoleon wrote to Latouche-Treville in command of the Toulon fleet, "and we shall be masters of the world." In less rhetorical moments he extended the necessary period to from two to fifteen days. Up to the spring of 1804 neither army nor flotilla was fully ready, and thereafter the crossing was always definitely conditioned upon a naval concentration. But the whole plan called for swift execution. As time lapsed, difficulties multiplied. Harbors silted up, transports were wrecked by storms, British defense measures on land and sea grew more formidable, the Continental situation became more threatening. The Boulogne army thus became more and more--what Napoleon perhaps falsely declared later it had always been--an army concentrated against Austria. To get a fleet into the Channel without a battle was almost impossible, and once in, its position would be dangerous in the extreme. Towards the end, in the opinion of the French student Colonel Desbriere, Napoleon's chief motive in pressing for fleet cooperation was the belief that it would lead to a decisive naval action which, though a defeat, would shift from his own head the odium of failure.