Blockade-running had now become a business speculation. But the great bulk of the trade was in very few hands, for the risks were great, and the capital involved was large. The initial cost of a blockade-runner was heavy; the officers were highly paid; a pilot well acquainted with the port to be attempted often demanded one thousand pounds for his services; and besides all this, it is to be remembered that on a fair calculation not above one trip in four was successful. It is computed that in three years there were built or despatched from the Clyde no less than one hundred and eleven swift steamers specially designed for the adventurous trade with the Confederate ports. Almost any day in August 1864, one of these vessels might have been seen cruising about at the Tail of the Bank, preparing to try her speed against the swiftest passenger steamers of the river. The _Douglas_ was in those days the fastest boat on the Mersey; but one of the new blockade-runners, named the _Colonel Lamb_, easily beat her, attaining on the trial a speed of sixteen and three-quarter knots (or about nineteen miles) per hour. A careful observer might almost have guessed the character of the enterprise for which a blockade-runner was designed by a scrutiny of her build. Two taper masts and a couple of short smoke-stacks were all that appeared above the deck; her object was to glide in the darkness past her watchers, and the tall spars of a heavily-rigged ship would have been too conspicuous a mark for eager eyes. Her hull was painted white, for experience showed that on dark nights or in thick weather that colour most easily escaped observation. Although she had considerable stowage-room, her draught was light, and she was propelled by paddle or side wheels, in order that she might turn readily in narrow or shallow waters. To aid their war-vessels in capturing and destroying light-heeled cruisers such as this, the Federal government built twenty-three small gunboats. They, too, drew but little water, and rarely exceeded five hundred tons burden. For armament they carried one eleven-inch pivot-gun and three howitzers—two of twenty-four pounds, and one of twenty pounds—well-chosen weapons for the work they had to do. Their weak point was their rate of speed, which did not amount to more than nine or ten knots an hour. So deficient were they in this respect, that a blockade-runner has been known to run out, get damaged, and sail round a gunboat into port again.