Friday, August 26, 2016

Delaware Breakwater Metes & Bounds


The Delaware Breakwater is situated at the entrance into the Delaware Bay near Cape Henlopen. The anchorage ground, or roadstead, is formed by a cove in the southern shore directly west of the pitch of the cape and the seaward end of an extensive shoal called the shears; the tail of which makes out from the shore about five miles up the bay , near the mouth of Broadkill Creek, from whence it extends eastward and terminates at a point about two miles to the northward of the shore at the Cape.
The Breakwater consist of an insulated dike or wall of stone, the transversal section of which is a trapezium, the base resting on the bottom, whilst the summit line forms the top of the works. The other sides represent the inner and outer slopes of the work, that to the seaward being much greater than the other. The inward slope is 45 degrees; the top is horizontal , 22 feet in breadth and raised 5-1/3 feet above the highest spring tide; the outward or sea slope is 89 feet n altitude upon a base of 1053 feet; these dimensions being measured in relation to a horizontal plane passing by a point 27 feet below the lowest spring tide. The base bears to the altitude nearly the same ratio as similar lines in the profile of the Cherbourg and Plymouth Breakwaters.
The opening or entrance from the ocean is 650 yards in width, between the north point of the cape and the east end of the Breakwater. At this entrance the harbor will be accessible during all winds coming from the sea.
The dike is formed in a straight line from E.S.E. To W.N.W. ; 1200 yards is the length of this portion of the work which is designed to serve the purposes of a breakwater. At a distance of 350 yards from the upper or western end of the breakwater ( which space forms the upper entrance), a similar dike of 500 yards in length , is projected in a direct line, W. by S. ½ S. forming an angle of 146 degree, 15 min, with the Breakwater. This work is designed more particularly as an icebreaker. The whole length of the two dikes above described ; which are now partly commenced will be 1700 yards; they will contain when finished 900,000 cubic yards of stone, composed of pieces of basaltic rock and granite weighing from a quarter of a ton to three tons and upward.
The depth of the water at low tide is from four to six fathoms throughout the harbor which will be formed by these works and the cove of the southern shore. It is calculated to afford a perfect shelter over a space of water surface of seven tenths of a square mile.
The object to be gained by the construction of an artificial harbor in this roadstead are to shelter vessels from the action of waves caused by the winds blowing from the E. to the N.W. round by the N. and also protect them against injuries arising from floating ice descending the bay from the N.W.

Source: Encyclopedia Americana : Tuesday , November 16, 1830 Issue Charleston Courier of Charleston, South Carolina.
From the pen of the Engineer engaged in the construction of the work.

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