Lighthouse Frequently Asked Questions
I am adding this section due to the number of messages I get asking specific questions. It's not that I don't appreciate the questions, I am creating this section for the people that have questions and don't ask them. If you have a lighthouse question, email it to me. It may be featured here in the future.
Q. Why are
lighthouses painted differently? Do these designs represent
something?
A. Lighthouses are painted different
colors and designs to make them daymarks. So, if you were a mariner
out at sea during the day, you could look for the lighthouse. Let's say for instance that you were off the coast of N.C. and you saw black and white swirling stripes down the lighthouse; you would then
know that you were by Cape Hatteras. Or if you spotted a lighthouse
that had black and white diamond shapes on it, you would then know
that you were farther south by Cape Lookout.
Q. If lighthouses are painted different to distinguish them during the day, how can you tell them apart in the dark?
A. Similar enough, each lighthouse also flashes
a different sequence of light for the same reason. Cape
Hatteras flashes a white light every 7.5 seconds. (The light rotates, but it gives the appearance of flashing from a
distance.) Cape Lookout flashes a white light every 15 seconds. So,
by scanning the horizon for the lighthouse, and then watching the
light, you were able to figure out where on the seaboard you
were.
Q. Why is the
coast off of Cape Hatteras called "The Graveyard of the
Atlantic"?
A. It is called the Graveyard of the
Atlantic because there has been a substantial number of vessels lost
(over 2300 since the early 1500s) in that particular area to the Diamond shoals. From what I have read, two different
"rivers" or currents that flow past there. The cold Labrador
current comes from the North, and the warm Gulf Stream current flows
up from the South. Mariners knew that these currents helped move
them along, so depending on which way they needed to go, they would
try and get into that prospective current. It just so happens that
the currents pass dangerously close to the Diamond Shoals, which led to many wrecks.
Q. Is there such a thing as the "Graveyard of the Pacific?" And if so, where is it?
A. Yes, there is a Graveyard of the Pacific. It is in the Pacific Northwest where the Columbia River meets the Pacific Ocean. The Columbia River is the second longest river in the United States at over 1200 miles long. By the time that volume of water collides with 20- to 30-foot ocean swells at the Pacific Ocean; it creates a hazardous bar that mariners must cross. This fact is why the area is known as the Graveyard of the Pacific.
Q. Are there any
more staffed lighthouses in the United States? Or are they all automated?
A. There is one last staffed lighthouse in the United States. It happens to be the very first lighthouse ever built on U.S. soil, which is the Boston Light on Little Brewster Island.
Q. How is the
power of a lighthouse rated?
A. Lighthouses are rated in two different ways. The fist is in nautical miles. In other words, how many miles out to sea a light is visible. For example, 20 nautical miles. The other way is in candlepower, which is a measure of luminous intensity, equal to 0.981 candelas.
Q. Which lighthouse is the brightest
in the world?
A. Two lighthouses share this distinction. The Phare du Créac'h, on the island of Ouessant, in France and the "new" Cape Point Lighthouse in South Africa are both visible for 60km, or about 37 miles.
Q. Which lighthouse is the brightest
in the United States?
A. The Charleston Lighthouse, also known as the Sullivan’s Island Lighthouse in South Carolina is the brightest in the United States. When it was first established in 1962, its beam was produced by six separate lights mounted on an aluminum base, which weighed 1,800 pounds. The six lights produced an amazing 28 million candlepower which was said to be visible for 70 miles at sea. After complaints from nearby neighbors and the dangers associated with servicing the lights, the Coast Guard cut it back to 1.5 million candlepower. The light is still visible for 26 miles on a clear night.
From 1958 to 1962, the Oak Island lighthouse in North Carolina held that distinction. When all of its lights were lit, it produced an astonishing 14 million candlepower, visible for 24 miles out to sea.
Q. Which
lighthouse is the tallest in the United States?
A. The Cape Hatteras Lighthouse in North
Carolina at 193 feet.
Q. Which
lighthouse is the tallest in the World?
A. The Île Vierge Lighthouse in France is the tallest at 271 feet. Some "lighthouse" like structures are taller but aren't considered a traditional lighthouse. The Île Vierge Lighthouse is the tallest "traditional" lighthouse.
Q. Why is it
that when I read about a lighthouse, one book will say its 153 feet
tall, and another will say 160 feet tall?
A. The
reason there are usually several different listed heights when
talking about a lighthouse because there are several different ways
to take the measurement. The height of a lighthouse is typically
measured from the ground to the top of the lantern room. Some measurements include a lightning rod, which can add upwards of 3 to 6
feet onto the height.
Q. What is a focal plane?
Q. What materials have been used to build lighthouses?
A. Lighthouses were made
out of many things. Back in the late 1700s to the early 1800s, most
were made out of wood. These types of towers traditionally did not last long. Most were lost to fire, gale winds, or huge waves. The
more popular building materials, the ones that have withstood the
test of time are granite, brick, iron, and even reinforced concrete.
Q.
What is Florida's most powerful
lighthouse?
A. The Hillsboro Inlet
lighthouse has a 2 million candlepower beacon and can be spotted
25 miles out to sea. It is also the last Florida lighthouse to be
built on shore. It was built in 1907.
Q. How many lighthouses are there in
the United States?
A. It
is estimated that about 680 lighthouses are remaining in the
U.S.
Q. How many lighthouses are there in
the world?
A. It
is estimated that there are 17,800 lighthouses in 250 countries throughout the world.
Q. What is the oldest lighthouse in the United States?
A. The Boston Lighthouse on Little
Brewster Island. It was built in 1716, but then heavily damaged in
the American Revolutionary War. In 1783, it was renovated and put
back into service. Since it was renovated, it is not considered the oldest "original" lighthouse, that question is answered below.
Q. What is the oldest
"original" lighthouse in the United States?
A. The
oldest original lighthouse in the U.S. is the Sandy Hook Lighthouse in New Jersey. It was
built in 1764, and is still flashing it's light today.
Q. What was used to make the "light"
in the lighthouses before electricity?
A. Several different types of liquids
were used burned in the lens including whale oil and kerosene. In one
case, natural gas was used since it was near a natural gas spring. This
lighthouse was the Barcelona Lighthouse in the Westfield, New York.
Q. Which state has the most lighthouse in the United States?
A. Michigan. It has over 120 lighthouses.
Q. How many states in the United States have lighthouses?
A. 37 states contain lighthouses.
Q. When was the first documented use of range lighthouses?
A. The first documented use of range lights was at Newburyport Harbor (Plum Island Lighthouse).
Q. Which coast has more lighthouses? East Coast or West coast?
A. The East Coast, which has 391 lighthouses. The West Coast has 94.