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New optic and a new era at Hillsboro Inlet

By Ralph Krugler

“Time marches on” is one of the truest statements ever uttered. For many lighthouses, the result of that reality is a spot on the doomsday list rather than a life in retirement. For the lucky ones out there, it’s just another era in the daily grind. For the skeletal tower at Hillsboro Inlet, Florida, a new era arrived in May 2021.

Hillsboro Inlet Lighthouse, Florida. Photo by Ralph Krugler.

From the lighthouse’s first day of service, March 8, 1907, to electrification on February 26, 1932, the illumination device inside the second-order Fresnel lens was an incandescent oil vapor (IOV) lamp.  It consisted of three mantles and would typically burn a gallon of kerosene per night.  Unfortunately, no photo of the device used at Hillsboro Inlet exists, but one of the founding members of the Hillsboro Lighthouse Preservation Society (HLPS), David Butler, drew what he perceived the device to be (seen at left).

The IOV had a bicycle-style hand pump that the keepers would use to maintain the 100-psi necessary to ensure a constant flow of oil from the reservoir to the burners.  The closest we have to a photo comes from the family of Keeper Thomas Knight in which the device can be seen behind the bullseye.

The only exception to the IOV providing the light for the lens came on the night of August 10, 1908, when Keeper Alfred Berghell had to fix the device. First Assistant Thomas Albury, who was on watch, could not get the oil to flow and so troubleshooting took place until the light was burning bright again. Until the IOV was operational, Berghell had hung a kerosene table lamp in the center of the lens. While not perfect, it kept the light shining.

The first step in the journey of “progress” came when the tower was electrified and three 250-watt bulbs replaced the three IOV jets. The brilliance of the light was retained until 1942. In WWII, many coastal lenses were extinguished completely, but Hillsboro was dimmed from 750 watts to only 50. The full intensity was returned as the lights along the coast were relit in August 1944.

Dual lamp system (U.S. Coast Guard)

The second step of the journey came in 1966.  As technology evolved, the brilliance of lightbulbs intensified. The three bulb system was reduced to a single 1000-watt bulb, with a second bulb for redundancy.

Time passed and the bulb shrunk while maintaining its intensity.  Quartz iodide bulbs were the next era, installed in 1978.

The biggest stumbling block for the lighthouse came in May 1993, when a drive gear broke and the future of the lens was in jeopardy.  Fortunately, the newly formed HLPS prevailed upon the USCG to restore the lens. A succession of low-intensity airport beacons substituted for the lens in the interim. When the light came back on in 1999, it was a single 1000-watt Xenon lamp — again with a second in redundancy — which remained until 2018. 

Halogen lamp system

Then, the short-lived halogen bulb era was upon us.  The “pro” for the change was that replacement bulbs were a mere fraction of the cost. The “con” was the life span.  The bulbs only lasted between 3 to 6 months, which wasn’t the worst part. The housing of the primary bulb had failed early on, resulting in the secondary bulb being the only operational device.

Despite requests for repair and the Coast Guard’s assurances, it never materialized.  This resulted in several late-night drives to the lighthouse to switch out the bulbs.

The last time this would happen was in early May of this year, as if the device was saying, “for old time’s sake.”

In January of 2021, BMC Ray Coleman (District 7, ATON Chief, USCG) was renting one of the keepers’ cottages with his family. He requested a tour of the lighthouse for his young children.  HLPS President Ken Herman and I provided the service and took the opportunity to get to know him better.  BMC Coleman was very appreciative of the efforts we go to in order to maintain the lighthouse, and was curious about our thoughts on conversion to LED. Since the original IOV had already been removed, never to return, the evolution to LED was a non-issue for us. Plus, we were under the impression that the halogen was just meant to be a temporary placeholder until the LED came available.

BMC Coleman and I were discussing the possibilities for the LED and he was uncertain which would be installed. I had seen the high-powered LED (SL-LED) from Sealite and shared the information with him. I was happy to see that the model chosen was that particular one.

Sealite’s High Output LED Lighthouse Light Source (SL-LED)

The parts from Sealite and installation crew arrived in April and the process was running fairly smoothly.  A new photo sensor was attached to the lantern ring at the base of the windows. It is connected to the control center; a metal box with the computer to operate the LED. This unit also has a relay cable to the existing lens motor drive panel, and a second cable that goes to the LED itself.

The pre-installation measurements had been done in error; and when it came time to lay out the cable, everyone realized the error all at once. The lights the crew had replaced to this point had all been stationary; whereas, Hillsboro has a revolving lens.  When the measurement was taken, the tape was run from the control unit to the floor, then to the base of the lens pedestal, up the pedestal, through the platform access hole, and stopping where the LED would be placed.

The crew working on the new optic installation

The problem is that when the motors activated, the cable to the LED would have been ripped out on the first rotation.  Fortunately, the wiring for the halogen unit had not been removed.  The light conversion project was halted for the day.  New measurements were taken going up the lantern, across to the center of the lens and down to the location for the LED. 

The crew ordered the new cable from the manufacturer in Australia. The two-week delay of course became a four-week delay, in which time the halogen had its final failure. 

At 8 AM on May 21, the crew returned, cable in hand. This time, the existing wiring was removed, so the installation had to be a success.

Ken Herman lays a cable to the LED optic

The LED unit comes with a focal plane height placement. The unit has a base onto which a LED pedestal is fastened.  Prior to installing the LED, the focal plane has to be assessed.  The package comes with a device to set the focal plane height for the LED.  Essentially, it is a removable spike that screws into the pedestal, the tip of which is where the LED will be centered. A line is measured from the tip of the spike to the center of the bullseye and is adjusted until a horizontal line is achieved.

After a couple trips to a local electrical parts store, and with daylight running out, it was time to set up the system.  A data cable (provided by the manufacturer) is run from the control unit to a laptop.  A simple setup program is run and the manufacturer suggests that the initial intensity of the LED be set between 30 and 50%.  Since Hillsboro has been the brightest lighthouse in continuous service in the world for quite some time now, 50% intensity was chosen.

Then, all systems were tested, retested and retested again. Several issues were addressed, but finally, shortly after 6 PM, all systems were “go.” At 6:32 PM the light from the sun was reduced enough to trigger the photo sensor and illuminated the LED for the first time.

The intensity of the LED was amazing to behold. With the halogen system, one could stand in the lantern on the walkway and look into the center of the lens when illuminated.  Trying to do that with the LED was a painful endeavor.

The LED is illuminated inside the Fresnel lens for the first time

Also, the entirety of the lantern was lit up as had never been seen previously.  I watched the beam shoot out to the horizon greater than before. On the shore side, it amused me to see the beam sweep across the various condos, lighting up the bedrooms and wondered how long it would take to get a complaint phone call.  So far… so good.

The unit has an optional GPS system, which we did not order. It can also be set to send weekly reports and alerts if there is a system failure.

The next era of lighthouse illumination devices is upon us. For traditionalists, they will not appreciate the change in color from a warm yellowish to a much harsher, brilliant, white.  That choice is yours.

As a side note: seeing the intensity of the beam from the ground later that night, we couldn’t help but wonder if the halogen had been centered perfectly in the focal plane; there was that much visible difference.

Hillsboro Lighthouse Preservation Society

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