Democratic Sentinel, Volume 20, Number 2, Rensselaer, Jasper County, 17 January 1896 — DARING ENGINEERING. [ARTICLE]

DARING ENGINEERING.

A Great Lighthouse in the Open Ocean. A difficult and costly piece of engineering has been undertaken by the I nited States Government in the projected establishment of a great lighthouse in the open ocean off Diamond Shoal, seven miles from the present Hatteras Light and bearing almost due east. This is one of the most daring schemes that army officers have dealt with since General Casey, chief of engineers, successfully undermined the great Washington monument and placed there a solid foundation expected to support that structure for ages to come. Surrounding this new plan, however, there is foreboding of failure, and it is predicted tints early that $1,000,000 is to be sunk literally as well as metaphorically tn the sea. If such a structure is placed there and stands without serious damage the onslaught of the seas for five years, according to a leading army engineer, this Government will have accomplished its greatest triumph in this branch of science. The height of the focal plane above water in the prospectus is given as 100 feet, and the structure is to stand in thirty-three feet of water, and to be supported on disk piles sunk to a depth of thirty feet in the sand. The diameter from centre to centre of vertical members of the foundation series is to be sixty feet, and the height of the floor of the house above water forty-seven feet. The main portion of the structure is to be constructed of forged steel members, with principal joints and connections formed of steel castings. A special feature of the design is to make all essential parts below the water line of massive dimensions, as well as all those parts above the water line which will be subject to the action of wind and waves. The use of bolts, keys, screws and other small sections or dimensions which would be rapidly weakened by corrosion, will be avoided as far as possible. Joints and connections are to be made absolutely rigid to all possible strains and to be as strong as the members themselves. This is to be effected by joining ends of members to steel cast hubs by the use of massive steel rings shrunk on in a manner approximating that followed in “built-up” gun construction. In the foundation series, besides the massive members necessary for the strength of the tower when in place, there will be certain other tie rods of lighter section, which are added for greater security to stiffen the framework while it is floated and while being placed and grounded on the shoal. It is proposed by the board to construct the screw pile structure in the harbor and float it out by steel cylindrical caissons calculated to give a draught of thirty feet when at sea. This part of the light is then to be sunk probably fifty feet down in the bottom by hydraulics until a firm hold is secured. It is then proposed to build up from the skeleton arrangement until the lightkeeper's apartments have been completed, and the height secured for the great lens which is to throw its light twenty-five miles in all directions. The work is to begin this winter, and it is proposed to complete the light in two or three years.