History of Beacons

Lighthouse and beacon surrounded by the ocean
Sand Key Lighthouse located off Key West as seen in the early 1900s. Photo: Monroe County Library

A Visual Positioning System

Despite 19th century efforts to improve maritime commerce, poor positioning accuracy still contributed to dozens of vessels grounding in the Florida Keys each year. The U.S. Coast Survey was tasked with developing navigational aids in the Florida Keys, including a series of unlighted reef beacons that visually warned ships of their proximity to the reef. Before modern, satellite-based GPS were in place to guide boaters, day beacons were a visual positioning system that helped mariners confirm their position on charts.

The first beacons in the Keys were primitive "screw pile" beacons installed in 2–4 feet of water at American Shoal, East Washerwoman, and Caesar Creek. The 9-foot long iron piles driven into the seafloor held 30 to 40-foot long mangrove wood posts. The posts were topped with a black colored barrel that could be seen with the naked eye from a distance of 2–3 miles and up to 6 miles using a spyglass.

Totten Beacons

Looking above and below the water line at a lighthouse and a single rod in the foreground
Beacon B at American Shoal is still visible above the water not far from the American Shoal lighthouse, which was completed in 1880. Photo: Matt Lawrence/NOAA

By 1853, construction began on more permanent markers, labeled alphabetically from "A" through "P". These would become known as the "Totten Beacons" after Lieutenant James B. Totten, the U.S. Army Assistant to the Coast Survey who oversaw their construction. Totten reported to his superiors that he had installed 14 of the 15 planned beacons by July 1855.

Each beacon consisted of several parts. At its base, a 9-foot long, 9-inch diameter cast iron screw pile was driven into the reef. The screw pile's top end was a 4-foot hollow pipe to accept the beacon's vertical shaft. For ease of transportation, the beacon's mast consisted of three sections, starting with a 14-foot cast-iron base inserted into a screw pile. The base was then bolted to a 10-foot long cast iron midsection via a set of collars. The mid-section, in turn, was bolted to a 16-foot long wrought iron upper spindle. The shaft of the upper spindle tapered from a 7.25-inch diameter at its base to 2 inches in diameter at the top. The lettered marker was mounted on two powerful hinges at the junction of the second section and the spindle, creating a vane that held the wrought iron letter inside of a 6-foot frame. The spindle's top was crowned with a lattice-work iron cylinder hoop, 6 feet high and 2.5 feet in diameter to give it extra visibility. Each beacon was painted in various patterns of black, white, and red, so that no two adjacent beacons had the same colors on like parts.

A drawing of a pole with a flag-like extension showing the letter A
A historic drawing outlining the plan for LT James Totten's unlit beacons. Image: NOAA Library

The Remaining Legacy

Following Totten's work, storms and hurricanes battered the beacons. Some remained standing for only a few years, while others lasted decades. The U. S. Lighthouse Board took over responsibility for the beacon's maintenance and by the 1870s had developed more substantial beacons that used stakes, tie rods, and turnbuckles to provide additional support to the beacon's mast.

Some of the new beacons replaced the single letter vane with a tri-vane design that made the letter visible from more angles. These newer style beacons also used screw piles that had a disc-shaped base similar to the screw piles used on several of the lighthouses installed on the Florida Keys reefs. Historical research suggests that the beacons were maintained until the 1920s, serving an important role protecting lives and property.

A line drawing of an object extending above the surface of water
Single vane beacon style with supporting turnbuckles. Although this depicts a number 2, Totten Beacons contained letters from A to P to mark the location on the reef tract. Image: U. S. Lighthouse Board, Notice to Mariners, No. 57 of 1873
A line drawing of an object extending above the surface of water
Tri-vane beacon style with supporting turnbuckles. This design, which replaced the single-vane design on many reefs, made the letter visible from more angles. Image: U. S. Lighthouse Board, Notice to Mariners, No. 57 of 1873