Rebuilding the disappeared granite wharf

When first built, Graves Light included a substantial wharf, built of huge granite blocks.

The sea has swept away all but four of the original massive stones. For years, divers have searched the bottom of the harbor around Graves Ledge and never found any of them.

So we rebuilt the wharf with 2-1/2 ton granite blocks recycled from an old New Hampshire railroad bridge. It was a complicated job.

With ACK Marine, we set three courses of granite blocks extending below most of the elevated wooden dock and a bit further into the harbor.

Guiding the blocks into place with precision required calm seas and a dead low tide. ACK set the first of the three courses of granite in a day.

The blocks were set in place in wet concrete with large holes bored through them.

To slow the inevitable destruction by the sea, the blocks were doubly held into place with massive steel pins that run through holes drilled through the entire thickness of each block and down into the ledge itself. Each pin was attached to the stone beneath the sea with high-tech, environmentally friendly epoxy.

ACK Marine then installed the wooden forms and poured a massive concrete slab behind the blocks to try and prevent heavy winter storms from knocking the whole thing to pieces.

Never know until you try!

Extra thanks to Mike S from King Pine for the helicopter photos and Michael B for the breathtaking overhead picture.

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How much of a pounding can it take from the sea?

We get a lot of questions about how much of a pounding this or that modification or reconstruction will take from the sea.

A lot of engineers and others helped us think things through before we drew up the plans and went to work.

This diagram shows the load calculations on the Oil House, with its new second story.

We built a new timberframe roof to replace the old, and added stainless steel reinforcements which the original roof didn’t have.

The precast marine concrete walls of the second floor are heavily reinforced and interlock with one another. They are bolted six feet into the ledge below.

Nearby pilings for the footbridge are made from 6-inch reinforced stainless steel pipe, welded to the original US Army Corps of Engineers steel pilings that were drilled six feet into the ledge. The original ones worked perfectly for decades until a big storm snapped them off like twigs.

The windows will be protected from hurricanes by anti-ballistic shutters.

That’s the plan, of course. The sea will decide for herself what works.

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How it looked up close

The Oil House project has generated a lot of interest in our restoration efforts, so we’d like to share some more photos that have been trickling in all week of our work on the second story.

Praise and respect for the whole crew! Thanks Anthony, Frank, Ben, Randy, Jared, Brad and Raivo for the excellent pictures from every possible angle. 

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Oil House gets a second story & new roof

Erickson Air Crane lowers the first wall panel of the second story of the Oil House.

In 25-knot winds and sub-freezing temperatures, a daring and dedicated crew of 30 put a second story and new roof on the Graves Light Oil House.

We have been working since last spring to convert the Oil House into a guest cottage.

A heavy-lift Erickson Air Crane helicopter ferried the five-ton marine concrete walls and a completed timberframe roof from a barge to Graves Ledge.

Waiting crews guided the massive pieces in place as the helicopter – Erickson’s civilian version of Sikorsky’s military CH-64 Tarhe Skycrane – neatly lowered them, one at a time, on the heavy granite Oil House.

The Oil House was built in 1905 to store whale oil used to fuel the Graves Light beacon. It is made of heavy granite blocks and has withstood all seas and weather ever since.

Making an equally tough second story was a task we gave to Carson Concrete, which pre-cast the four interlocking side panels in Pennsylvania and sent them to Boston by barge.

The original wooden roof also survived, but was too battered to salvage. Haystack Joinery in Maine built a magnificent timberframe replacement on shore. We helicoptered it out in one piece along with the concrete second story.

Hats off to our most daring and dedicated crew, which pulled off the job flawlessly on the icy ledge. Everyone’s safe.  

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