In 1841 the first Fresnel lens to be used in this country was imported from France and installed in the south tower. In 1898 an electric arc lamp replaced oil lamps in the south tower, this being the first primary lighthouse in the United States to use electric light. The electric arc lamp was equipped with a bivalve lens of the new lighting type. This lens, weighing over 7 tons, revolved in 10 seconds, and gave a flash every 5 seconds, lasting 0.3 seconds. The Navesink Light was the only shore station having a plant for generating electricity. Its estimated candlepower was 25,000,000 making it the most powerful coast light in the United States. Although on account of the curvature of the earth, the light itself could not be seen more than 22 miles, its beam was reported to have been observed in the sky at a distance of 70 nautical miles.

After the establishment of this electric flashing light many complaints were made by residents of the neighborhood of the great discomfort and annoyance caused by the brilliancy of the flash. This was remedied by darkening several of the lantern panels on the land side. The light was later changed to an electric incandescent light of 9,000,000 candlepower. With the improvement in floating aids, however, this lighthouse lost some of its early importance, and the candlepower was reduced to 5,000 candlepower. It was changed to unwatched in 1949. The light was discontinued in 1952 and used as a daybeacon until 1963. (3) (4)