Graves Light gets another first-order Fresnel lens

gl-john-nelson-randy-clark-do-final-fitBig news, everybody. Graves Light received a little taste of a genuine first-order Fresnel lens, similar to the original 1905 lens that sent out a 350,000-candlepower beam across the harbor.

The Coast Guard is still in charge of the navigational aids at Graves, so we couldn’t make the beacon shine like it did before the original giant Fresnel lens was removed in 1975. Since 1905, Graves had been the most powerful lighthouse in New England. Not so any more.

So we did the next-best thing by reconstructing part of the lens with pieces from lighthouses around the world. We assembled them as part of the interior decor in a way that won’t interfere with the modern, solar-powered lamp.

What’s a first-order Fresnel lens?

John and Randy assemble the flash panels to adorn the kitchen on the watch deck.

For a lighthouse, a Fresnel lens is a beehive-shaped compound lens made up of rings of glass prisms that cast parallel beams of light.

It is named after its inventor, French physicist Augustin Jean Fresnel (1788-1827), who had a special understanding of the physics of light.

Lighthouse lenses are divided according to size and light focal length, a category called “order.” Formally there are eight orders of Fresnel lenses, with the first-order being the largest. (There is also a 3-1/2-order lens. Two larger lenses were ultimately developed.)

A first-order lens casts a beam that can be seen more than 20 miles away. Only the curvature of the Earth prevents it from shining further on a clear night.

Fresnel lenses are made of heavy glass prisms housed in large brass or bronze frames, assembled as panels and arranged in a circle. The entire assembly of an operating Fresnel lens rotated on mechanical carriage or a pool of mercury, and in some parts of the world, still does. That liquid heavy metal ensured steady, constant, friction-free rotation, regardless of the weather, on a corrosion-free surface. The Coast Guard recovered 400 pounds of mercury from Graves when it removed the lens. Our new lens is stationary and won’t be used as an aid to navigation, so there’s no rotation mechanism or mercury.

Where did the new Graves first-order Fresnel lens come from?

We assembled the new Graves lens from several antique first-order lenses from decommissioned or modernized lighthouses outside the United States. Nearly all first-order Fresnel lenses have been destroyed, or are owned by governments as legacy artifacts. No complete first-order Fresnel lens exists in private hands, anywhere in the world.

Working through Chance Brothers Lighthouse Engineers of Melbourne, Australia, we bought pieces from English lenses built between 1880 and 1920.

Wyatt designed the bronze frame by computer, and built a full-scale wooden mockup.

Wyatt designed the bronze frame by computer, and built a full-scale wooden mockup. Then he assembled the frame on the mainland to make sure everything fit.

Reconstructing a lens

A first-order Fresnel lens would generally consist of glass prisms assembled in about 45 panels.

The panels are stacked three high and arranged in a circle. The lower and upper panels are called catadioptric panels and bend the light by reflection like a mirror. The center sections, or flash panels, are dioptric prisms which concentrate the light like a magnifying glass.

We acquired glass prisms to fill 15 panels. For considerations of living space and climate control – and for the practical matter of finding enough prisms – we did not attempt to rebuild an entire first-order lens nor could we. These panels are so scarce, it appears there may be no more to be found!

The objective was to illustrate the wonder of a First Order lens without taking over our kitchen.

No shop drawings for assembling a lens like this exist. It’s been said the factories that made them in England and France were destroyed during World War II. Our own Wyatt designed a custom skeleton frame using SolidWorks software, and uploaded the specifications to a water jet cutter, producing a rigid structure out of 1/2-inch bronze plate.

The assembly in our shop allowed us to correct mistakes, make sure the glass prisms fit properly, and refine each frame to ensure a good fit-out on station.

We packed each completed panel in wooden crates, brought them to Graves Light aboard Miss Cuddy, and winched them halfway up the lighthouse to the entrance, and hand carried them up the tower for installation.

After assembly, we found that the lens focused sunlight inward and melted our first aid kit. We knew from our neighbor Sally Snowman, keeper of Boston Light, and our visit to the Castle Morro lighthouse in Havana, that the old Fresnel lens lighthouses had interior curtains to block the sun by day. Both the Boston and Havana lighthouses still have operational Fresnel lenses.

So we went to Zimman’s for a bolt of the proper cloth. Our own Keeper Lynn is creating a custom curtain to prevent the sunlight from starting a fire, without the curtain obstructing the navigational lamp.

Vital statistics

  • Manufacturer: Chance Brothers of England
  • Grade: First Order Lens
  • Origin: From several lighthouses worldwide, circa 1880-1920
  • Weight of a complete sense: 3 tons
  • Weight of our lens apparatus: 1 ton
  • Height: 9 feet
  • Diameter: 6.5 feet
  • Light strength: Approximately 350,000 candlepower with kerosene burner

Where’s the original?

The original Graves Light lens, made in Paris by Barbier, Bernard and Turenne, is in the possession of the Smithsonian Institution in Washington, D.C. It isn’t on display, but is probably crated up in a warehouse. The Smithsonian loans out many of its pieces for public display, but federal law forbids the original Graves lens from being exposed to weather, so we couldn’t move it back to the lighthouse even if the Smithsonian would let us (which it won’t.)

The Coast Guard loans out Fresnel lenses under strict conditions, but requires that they be kept in climate-controlled environments, and, for preservation purposes, forbids them to be kept in lantern rooms.

See Theresa Levitt’s biography of optical genius Augustin Fresnel and his remarkable impact on lighthouses and navigation, A Short Bright Flash: Augustin Fresnel and the Birth of the Modern Lighthouse (Norton, 2013).

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Original drawings aid in door restoration

These custom-built stainless steel replacement hinges should last another hundred years.

These custom-built stainless steel replacement hinges should last another hundred years.

The leaky bronze doors on the Watch Deck needed new hinges to create a perfect seal against the weather.

We just couldn’t buy them in a store, or even find antique originals.

So we went back to the drawing board and used the original architectural drawings of Graves Light from 1903.

Those drawings included sketches and dimensions of the original hinges.

John Nelson of Nelson Metal Fabrication has fixed the leaky doors. John did a lot of great work for us already, and now it was time for more.

Using the original designs as a guide, John machined new stainless hinges to perfectly match the damaged old ones. Now the doors shut tight! The hinges should last until the 22nd century, at least.

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Mahogany kitchen benches go in this week

Nat of NMT Woodworking shows some of the mahogany benches he built for our kitchen.

Nat of NMT Woodworking shows some of the mahogany benches he built for our kitchen.

Meanwhile, Nat and the lads at NMT Woodworking in South Portland, Maine, have been busy.

Living space at Graves Light is at a premium – none mores than the kitchen on Level 6. That’s the old Watch Room, a circular room of bronze and steel that sits on top of the granite tower and just below the glass Lamp Room.

The NMT crew created this custom mahogany bench seat to fit against the curved wall.

They built it for serious chowder eating. The marine-grade mahogany is able to withstand extreme temperatures and salt air.

You can see how the curvature matches that of the bronze kitchen stove that our man Wyatt designed over the winter.

Nat will be installing the bench system this week, weather permitting, as always. So stay tuned.

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Engineer who removed original Fresnel lens returns to Graves

Engineer Ron Fiore explains to Dave how he devised the system to remove the original Fresnel Lens from Graves.

On the deck of Graves Light for the first time since 1975, engineer Ron Fiore explains to Dave how he devised the system to remove the original Fresnel Lens from Graves.

Well, the best part of this whole lighthouse experience continues to be all the great people we meet.

Today we met Ron Fiore, the structural engineer who devised the method of removing the gigantic First Order Fresnel lens back in 1975.

That lens blasted out a 3.2 million candlepower beam for 70 years straight. The lamp required a full-time crew to operate and maintain, so the Coast Guard had it taken out and replaced with an automated electric beacon.

Ron told us all the details about how he built a custom crane to gently lower the priceless lens – it weighed 2 tons and measured 12 feet tall and 9 feet across – down one story into the watch room.

Then he and the crew removed part of a wall to slide the lens past the sloping tower and drop it 60 feet to the dock, where a Coast Guard boat plucked it onto the deck. 

Legendary New England maritime history author Edward Rowe Snow made an appearance, instructing the crew to wave (as he was filming the feat) but the workers were too busy – and scared – to respond.

The next year Ron and his wife visited the lens again, this time at the Smithsonian!

The Fresnel lens was made in France by Barbier, Benard & Turenne in 1904, and was installed in 1905. After the 1975 removal, the Coast Guard installed an automated electric beacon, powered from land by an underwater cable. That cable broke, so in 2001 the Coast Guard installed the present solar-powered lamp, the Hydrosphere Vega VRB-25, made in the U.K.

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Custom building a lighthouse kitchen stove

With his high school engineering education and his own imagination, Wyatt designs the stove.

With his high school engineering education and his own imagination, Wyatt designs the stove for a small space with curved walls.

Without any flat interior walls, a lighthouse needs custom-made everything. Since kitchen space is the most precious, and the sea air corrosive of steel, conventional appliances just won’t work.

Wyatt's bronze stovetop, after it came back from the metal shop.

Wyatt’s bronze stovetop, fresh from the metal shop.

Luckily, Wyatt is studying engineering in high school. After drawing out the exact curve of the interior wall of the watch room, Wyatt whipped up a curved stovetop design on his computer.

We sent Wyatt’s design to a metal shop, which crafted a stovetop out of 1/2-inch thick bronze, using a water jet cutter.

The rest is up to us. We’re modifying propane barbecue burners to fit under the top and will design a curved faceplate for the knobs.

Can you smell a delicious chowder simmering this summer?

The stovetop design, from computer to metal shop.

The stovetop design: Wyatt measured the curve from the lighthouse radius, for fabrication from a sheet of half-inch-thick bronze.

 

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On-shore basement project: Building a lighthouse desk

Winter is a great time for on-shore basement projects for the lighthouse.

We converted an old oak desk into a keeper’s desk. First, we crafted a new top to fit the curved inner walls of the tower. We secured it to the two base drawer units with brass fasteners (no rusty steel in the lighthouse environment) and stained it to match.

The desk is installed on the 4th level, which will be the master bedroom. Next, we’ll start building a space-saving Murphy bed, whose mattress can be stored vertically when not in use, and pulled down flat for the evening.

 

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Castle Morro lighthouse keeper in Havana gives Graves Light a tour

The keeper of the Castle Morro lighthouse in Havana, Cuba, shows us the original 1845 Fresnel lens.

The keeper of the Castle Morro lighthouse in Havana, Cuba, shows us the original 1845 Fresnel lens. Manually wound every 3 hours, the lens sits on its original pool of mercury for smooth rotation.

As authentic as it gets: Graves Light got an up-close look at the historic 1744 Castle Morro lighthouse in Havana harbor, Cuba, and saw an original Fresnel lens in about as original a state as possible.

Enrizio, keeper of the Havana lighthouse, takes us on a visit through Castle Morro.

Enrizio, keeper of the Havana lighthouse, takes us on a visit through Castle Morro.

On a quick visit to the island last weekend, Graves Light keepers Lynn and Dave talked their way into the lighthouse just as the Morro keeper was reporting for duty.

The light is closed to the public. Lunchpail in hand, Enrizio, the friendly keeper, gave us fellow keepers a tour and took us up to the lantern room.

It was like climbing back in time. What appears to be the original Third Order bivalve Fresnel lens is still in operation.

The lens was made in about 1845 by BBT Paris, the same manufacturer of the old First Order lens at Graves Light, which is now at the Smithsonian Institution.

The keeper fired up the early hand-cranked motor that spins the lens, which still floats smoothly on its mercury bath. Half the windows in the lantern room are cracked or broken out, but the lens produces a brilliant double white flash every 15 seconds. The mechanism is still manually wound every three hours.

The lens was modified by “the French” in the 1950s with the addition of small reflecting panels to bend some of the beam 45 degrees upward so that aircraft could navigate by its light. Other than those panels and an electric lamp that uses a 70 watt halogen bulb, the entire apparatus appears completely original.

Each evening, the keeper withdraws the curtains and engages the mechanism to spin the lens. By day, the curtains are drawn to prevent the sun from entering the lens and starting a fire inside.

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Diver’s discovery helps us complete our interior doors

Chris, of Boston Scuba, discovered an original Graves Light porcelain door knob on the bottom of Boston Harbor.

Chris, of Boston Scuba, discovered an original Graves Light porcelain door knob on the bottom of Boston Harbor.

Discovering the original from under water let us install authentic replacements.

Discovering the original from under water let us install authentic replacements from a wrecking company..

Some of the clues to the faithful reconstruction of the interior of Graves Light have come from the bottom of Boston Harbor.

Chris, a diver from Boston Scuba, found yet another artifact offshore at The Graves.

Pictured in his hand is a heavily weathered porcelain door knob.

We had already restored the surviving interior door and built two copies on Nantucket, but we didn’t know what the original knobs looked like. Now we do.

So we found four antique sets of knobs at a local wrecking company. Voila! The doors are now complete. Thanks, Chris!

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Glass jewels for lantern room get cast on Nantucket

Getting the glass jewels ready for the Watch Room skylights/Lantern Room floor panels.

Alison MacDonald of ACKfire studios gets the replacement glass jewels ready for the Watch Room skylights/Lantern Room floor panels.

We’re getting down to the fine details now. The missing glass jewels that form the skylights for the Watch Room ceiling and the floor pieces for the Lantern Room are now being cast.

The Nantucket artisans at Ackfire Studios are hard at work right now creating replacements for the missing heavy glass jewels embedded in the round bronze skylight frames.

Alison MacDonald of Ackfire visited Graves Light in April to examine the job and take measurements.

Now, the colored glass disks have been cut and are being cast in tiny molds within a large kiln.

We love our local artist community! Here is the Ackfire crew cutting individual discs of glass which will be melted and formed in these little molds.

The resulting glass jewels will be glazed into the lantern floor this month.

These glass pieces are reproductions of the missing original glass from the 1903 architectural design, and are copied from the remaining originals.

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Oak ceiling is put in place

G installs the 5th floor ceiling

G installs the new 5th floor ceiling, an exact reproduction of the original, surviving parts of which were left in place.

Remember the oak ceiling we showed being built on Nantucket back in April? It’s now installed at Graves Light.

Karl installs the 5th floor ceiling

Karl Phillips puts the new oak ceiling panels in place.

Master carpenter Karl Phillips built perfect replicas at his Driftwood Construction shop, based on surviving original panels and the original architectural drawings.

Karl and G put the new oak panels in place up on the 5th floor library of the lighthouse. G is performing the trimming and shaping.

Karl did most of the other woodwork at Graves, too, including reconstructed oak windows based on the original casement design, interior oak window panels and sills, interior oak doors, and the mahogany staircase handrails.

As we’d previously noted, we decided to leave the original damaged ceiling panels in place, covering them with the new ones to give some future renovators a surprise.

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