The obstructions were to be placed on both sides of the crest of the bar, so that the same forces which created the bar might be relied on to keep them in their places.
The bar was not to be obstructed entirely; for natural forces would soon open a new passage, since the rivers must discharge themselves by some outlet; but to be only partially obstructed, so that, while this channel was ruined, no old one, like Swash or Sanford, should be improved, or a new one formed.
The vessels were so placed that on the channel course it would be difficult to draw a line through any part of it that would not be intercepted by one of them. A ship, therefore, endeavoring to make her way out or in could not, by taking the bearings of any point of departure, as she could not sail on any straight line.
The vessels were placed checkerwise, at some distance from each other, so as to create an artificial unevenness of the bottom, remotely resembling Hell Gate and Holmes’s Hole, which unevenness would give rise to eddies, counter-currents and whirlpools, adding so seriously to the difficulties of navigation that it could only be practicable by steamers, or with a very commanding breeze.
The execution of this plan was begun by buoying out the channel and circumscribing within four points the space where the vessels were all to be sunk, as follows:
*
S. W. * THE BAR. * N. E.
*
The distance between the points from S. W. to N. E. is about an eighth of a mile; the breadth perhaps half as much. It was no part of the plan to build a wall of ships across, but to drop them at a little distance from each other, on the principles above stated, closing the channel to navigation, but leaving it open to the water.
Work was resumed on Friday morning, the 20th, the Ottawa and Pocahontas bringing the ships to their stations. The placing of them was an operation of considerable nicety, especially as some of the vessels were so deep as to be with difficulty dragged on the bar, except at high water. A graver hindrance to their exact location was found in the imperfection of the arrangement for sinking, several of the ships remaining afloat so long after the plug was knocked out, that they swung out of position. They were, nevertheless, finally placed very nearly according to the plan. Great credit was earned by Mr. Bradbury and Mr. Godfrey for the successful execution of so difficult an undertaking. The last ship, the Archer, closed the only remaining gap, and the manner in which Mr. Bradbury took her in with the Pocahontas and then extricated the latter from her perilous position, filled the fleet with admiration for his skillful seamanship and cool daring. By half-past ten the last plug was drawn, and every ship of the sixteen was either sunk or sinking.