In 1843, Inspector I. W. P. Lewis, of the Lighthouse Service, emphasized the great need for a lighthouse on Minots Ledge and his judgment was sustained by Capt. William H. Swift, of the United States Topographical Bureau, who recommended an iron-pile lighthouse as offering less resistance to the waves than a stone tower.
The ledge was barely 20 feet wide and was exposed at low tide, being dry only 2 or 3 hours a day. On this narrow rock construction was begun in the spring of 1847 of a 75-foot open-work iron light structure. The men could only work on very calm days when the tide was at its ebb. The work was conducted from a schooner which remained near the ledge, unless the sea was rough, with the workmen sleeping on board. If a storm threatened, the schooner put into Cohasset Harbor until it was over.
Nine holes were drilled into the solid rock, each 12 inches wide and 5 feet deep. Eight were placed in a circle, 25 feet in diameter, with the ninth in the center. Iron piling, 10 inches in diameter were then cemented into each hole. Four men worked in 20-minute shifts at the drilling from a triangle, set on heavy spars, which supported a platform high above the ledge, on which the drilling machinery was installed.
All the apparatus was swept from the rock by two different storms in the summer of 1847. Workmen were swept into the sea several times, but none was drowned. Work had to be stopped for the winter in October 1847 and begun again in the spring of 1848, but by September of that year the nine holes had been drilled and the nine iron piles placed. The outer piles started toward the center to a 14-foot circumference, 38 feet above the uneven surface of the ledge. These were braced horizontally by iron rods at 19-foot intervals. Braces planned to strengthen the lower part of the tower were omitted on the theory that they would lessen rather than increase the over-all security of the edifice. However, it was where these braces were planned to go, that the structure actually broke off later.
A cast-iron spider, or capping, weighing 5 tons was secured to the top of this piling. The keeper’s quarters were erected on top of this. Finally a 16-sided lantern room at the very top, housed a Fresnel lantern, with 15 reflectors. The light, a fixed beacon with an arc of 210°, was first lighted January 1, 1850.
The first keeper, Isaac Dunham, was confident the light structure was not safe and wrote Washington requesting that it be strengthened. When no action resulted he resigned on October 7, 1850.
Capt. John W. Bennett, who succeeded him openly scoffed at his predecessor’s fears. He hired new assistants including an Englishman named Joseph Wilson and a Portuguese named Joseph Antoine. Two keepers remained at the light at all times.
The braces of the structure were soon showing signs of strain, however, and were constantly having to be removed, taken to the mainland and strengthened and straightened. A terrific northeast storm a few weeks after he took charge, changed Bennett’s mind and he officially reported the tower as in danger. A committee, delegated to investigate, arrived during a perfectly calm sea and returned to Boston, deciding nothing should be done.
On March 16, 1851, during another terrible storm, the keepers deciding the lantern room was unsafe, retreated down into the store room, where they cowered for 4 days and nights, only occasionally climbing to the lantern to repair some damage done by the storm. The violent pitching and swaying of the tower almost knocked them off the rungs of the ladder, when they did. A relatively calm spell followed during which the braces were tightened.
