Hillsboro Inlet lighthouse
The Hillsboro Inlet Lighthouse has weathered many hurricanes, including the one in 1926
that took away about six hundred feet of beach. The erosion was so great that much of the
area around the lighthouse was washed away, exposing the concrete pilings that support the
structure. Fortunately the lighthouse had a strong foundation. Many attempts were made to
stop the beach erosion including the use of wooden barriers and piled up brush along the
shore but they failed until huge granite boulders were placed from the lighthouse out into
The task of building a lighthouse foundation was intensive. Sand was removed down to
the bedrock. Holes were then made in the solid rock using chisels, pickaxes, and heavy
drills. Bolts were then set into the holes and fixed firmly in place with molten lead.
Even in brick and granite lighthouses this method was frequently used. For some
lighthouse foundations, massive steel screws were driven into the soft limestone to anchor
the lighthouse. Either method proved effective.
Like other skeletal lighthouses, the Hillsboro Inlet
lighthouse was fabricated in the Detroit but others like
it were built in New Jersey and New York. They were first assembled to ensure that
everything fit properly, then dismantled, packed, and shipped to their final destinations.
The cast-iron central tube measures nine feet across and has a double-thick wall with a
few inches of space between the walls. This added strength to the tower and insulated it,
keeping it a bit cooler in the summer. The lighthouse stands 136 feet tall and became
unmanned in 1974.
The diamond-shaped, curved panes of glass in the lantern room of the Hillsboro Inlet
Lighthouse are unusual and were very difficult to produce at the time. They were used
because they prevented the light from being cut off by any horizontal window framing as
the beacon rotated. The clamshell lens, also found in the lighthouse at Cape San Blas, was
an improved version of the more traditional beehive Fresnel lens design. Made in 1907 in
France, this lens had 356 polished optical glass prisms held in place by a brass framework
and was 9 feet in diameter. It would cost several million dollars to duplicate this lens
today, so smaller beacons with plastic lenses are now used.
The clamshell lens mechanism sat in a circular raceway holding five hundred
pounds of liquid mercury that floated the heavy lens so it could easily turn without the
use of ball bearings. Unfortunately, the mercury would evaporate in the hot Florida sun,
poisoning the air inside the lantern room although no one realized the dangers back then.
The mercury was also handled frequently by the lighthouse keeper when he cleaned it by
filtering adding to the danger.
Hillsboro Inlet was and still is a treacherous stretch of waterway, especially where it
meets the Atlantic. It was windy the day I visited the lighthouse, and even the larger
boats were having trouble navigating their way through the pass.
During World War II, many ships were sunk along Floridas Atlantic coast. German
submarines would sit offshore and use the lights of the town to silhouette passing ships,
making them easy targets. The tanker Lubrofol was sunk by a German submarine off
the coast of Hillsboro Inlet, leaving the beaches fouled with oil. The Hillsboro Inlet
Lighthouse was used as an observation platform to help spot submarines as were other
Florida lighthouses, but it was a difficult task. Air patrols were the most effective tool
to find submarines and because of those patrols, several submarines were sunk; one still
sits in three hundred feet of water just south of Hillsboro.
The lighthouse and grounds are closed to the public. Just to get close, you have to
pass through the private Hillsboro Club, and they arent very fond of sightseers. You
can get a good look at the lighthouse from the bridge, but the best view is from the
beaches across the inlet. The Hillsboro Lighthouse Preservation Society works with the
Coast Guard and occassionally opens the lighthouse to the public. The official webpage for the Society and information about upcoming tours go to their homepage.