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Lighthouse Preservation

Photos Courtesy Of The National Park Service

Far north of the shining city lights lies a place where the water is clear and bright. In this place is housed a beacon that has guided mariners safely home for more than a century.

However, after so many years, the structure itself needed its own assistance. In 2011, the lighthouse on SouthManitouIsland in Michigan underwent a restoration and exterior whitewashing that returned the building to its heyday.

A History Lesson

Located 8 miles northwest of the town of Glen Arbor, South Manitou is considered a part of the Sleeping Bear Dunes National Lakeshore. This area’s rich history dates to 1673 when the islands were first mapped by the French explorer Louis Joliet. In the early 1800s, sailed schooners transiting the Great Lakes used South Manitou as a means of navigation, but the island became most significant for fueling and feeding the steamboat crews transporting goods from the southernmost ports on Lake Michigan through the Straits of Mackinac to ports near Detroit.

The site of the current lighthouse has been home to three different configurations during the 1800s, with the most current one erected in 1871. The lighthouse stands 104 feet tall, and is connected by an enclosed hallway that leads to the two-story light keeper’s quarters. Imagine the men who constructed this monumental beacon, which by its mere location, must have logistically taken a considerable number of trips across Manitou passage to transport all of the large hand-chiseled limestone blocks that form the radius of the structure's foundation. The enormity of the task was compounded by the extraordinary number of bricks used to form the inner and outer walls that combined were 3 feet thick. Due to the close proximity of Lake Michigan and the consistency of the sand, just digging the foundation must have been a monumental task. One rumor is that the foundation is almost as deep as the lighthouse is tall, and the limestone blocks used are set on oak timbers at the base of the construction.

Safety First

The National Park Service has a strong commitment to safety that was paramount in completing the preservation of the exterior of the lighthouse. At the beginning of the project, all those involved received training in the work cage used by the park employees. This 3-foot by 3-foot cage, suspended by 7x19 strand galvanized-steel cable, was rigged from the top walkway by a ¾-inch-cable anchor point wrapped around the circumference of the lighthouse three times and stayed by cable clamps. Anti-chafing gear also was used to protect the cable whenever it came in contact with the structure. This device was equipped with a safety brake to prevent the basket from free-falling in the event of a motor or power failure. Additionally, safety and self-rescue drills were conducted to ensure that everyone required to work in the basket, as well as island maintenance personnel, were well-trained in case of an emergency. Personal safety gear consisted of a full-body harness that allowed for longer suspension time in the event of a fall, without cutting off blood to the femoral arteries. This harness also was equipped with suspension trauma straps that allowed the victim of a fall the ability to keep pressure off other vital areas until a rescue could be achieved. Workers were attached to a ⅝-inch braided lifeline, capable of withstanding a 5,000-pound shock load; the harness was attached to this apparatus via a 3-foot rip-stitch lanyard and rope grab. For on-site assisted rescues, a six-pin rappel rig on the top of the lifeline was anchored to a suitable point at the top of the lighthouse. Also developed was a means to raise an unconscious victimt to a sufficient height to clear the basket and be lowered to the ground by the rappel rig. Daily rigging checks were performed to ensure all gear was secure before placing a man in the basket.

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The whitewash used on the lighthouse consisted of hydrated lime and water mixed to the consistency of a light pancake batter. Sometimes salt was added to inhibit algae growth and improve the slaking process, which allows the mixture to stand for at least 12 hours before being re-stirred for use. This process is essential to create the chemical reaction that must occur between the lime and water to form microscopic crystalline structures to improve

The tower of the 1871 lighthouse on South Manitou Island in Michigan received a makeover using a whitewash comprised of hydrated lime and water.

durability and adhesion. A small amount of acrylic latex additive also was incorporated to improve the bonding of the whitewash to the brick; a diluted formula of this additive was used as a pre-primer to pre-hydrate the surface and improve adhesion. Preparation of the old surface was essential to achieve a good bond as well. Old whitewash that had developed algae growth under its surface had to be removed manually with scrapers and any other loose material stabilized before applying bonding primer or whitewash.

Weather Conditions

Weather was also a consideration in order to avoid spalling—or cracks—in the new whitewash due to accelerated drying time from the sun and wind. These factors were the hardest to control, especially with constant wind on the island, but crews worked on the shaded side in the morning if the wind conditions were favorable.

Wind was also a safety factor for the stability of the basket, which was suspended by a single cable with two outrigger wheels that contacted the lighthouse surface. Two taglines were used on each outer corner, and these were secured to a fixed point toward the bottom of the lighthouse to keep the basket positioned securely against the wall. A safety monitor was positioned on the ground to assist the operator during location moves and to readjust taglines. Imagine how nervous the old Coast Guardsmen must have felt doing this task from a boatswain's chair with little or no safety equipment.

Anyone who visits South Manitou can only stand in awe of the spectacular view from the Lake Michigan lighthouse. The sheer beauty and grandeur of this freshwater archipelago is sure to provide a memorable experience.

Chris LaFleur is a maintenance employee who worked on the restoration project at Sleeping Bear Dunes National Lakeshore in Empire, Mich. Reach him at clafleur@nps.gov .

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