Last summer, a Coast Guard rescue helicopter carried some unusual cargo across Boston Harbor: two 1,100-pound pieces of cast iron that would form part of the pedestal for Graves Light’s new beacon. “That was probably the most nail-biting part,” says Dave Waller, one of the 119-year-old light station’s owners.

Waller has spent nine years reuniting the lighthouse with a Fresnel lens—a type of lens that uses cast-glass prisms to focus and direct light, creating a strong beam. The light station illuminated Boston Harbor with one when it opened in 1905. The Coast Guard removed the original Fresnel lens when it automated the lighthouse in 1975, donating the lens to the Smithsonian.

After Waller and his wife, Lynn, purchased Graves Light in 2013, they restored most of the structure. According to Dave Waller, they were still disappointed by its “pathetic, modern light” and decided to replace it with a Fresnel lens similar to the original. “[Graves] was the brightest light north of Cape Cod when it was built,” he says. “And it had a magnificent lens built in France.”

He found an Australian lighthouse engineer who helped source the antique pieces of the replacement lens from as far away as Tasmania, and the couple’s two teenage sons helped build a frame. “The [frame] pieces that were missing, we had to make from scratch out of brass,” Waller says.

Installation of the lens is mostly complete, and once it is turned on, the light will be powered by solar panels. Waller says the Coast Guard has already updated its navigational charts to reflect the lens’s distinct flash pattern. “There’s something cool about the lighthouse staying true to its original function,” he adds. “It’s not just a quaint seaside item. It’s doing its duty that it was built for.”