I stumbled across this article about ships. Thought I'd put this here, nothing too technical but still educational. I know some folks don't follow links. My hats off to the folks who wrote this...
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Not many people have an opportunity to get this close to a container ship. Those who do may see icons that impart important information. For example, those black brackets to the right of the company name indicate where the tugboat is supposed to push. Photo by David Webster Smith
The Secret Language of Ships
Signs and symbols on the sides of ships tell stories about an industry few outsiders understand.
Credits
Text by Erin Van Rheenen
Photos by David Webster Smith
April 10, 2018 | 1,700 words, about 8 minutes
Approaching the container ship in San Francisco Bay, the tugboat looks like a pit bull puppy chasing an eighteen-wheeler. When the vessels are an arm’s length apart, the ship’s mate throws down a line. Now leashed to the ship, the tug can push and pull it around the bay. Big ships can’t easily slow down or maneuver by themselves—they’re meant for going in a straight line.
Tugboat crews routinely encounter what few of us will ever see. They easily read a vessel’s size, shape, function, and features, while deciphering at a glance the mysterious numbers, letters, and symbols on a ship’s hull. To non-mariners, the markings look like hieroglyphs. For those in the know, they speak volumes about a particular ship and also about the shipping industry.
Oceangoing vessels carry over 80 percent of the world’s trade, with more than 90,000 merchant ships plying international waters. Tankers, bulk carriers, and container ships—the largest things on Earth that move—are by far the most important modes of transportation of our time. They convey billions of tonnes of goods every year, bringing us everything from cars to crude oil to containers jammed with fidget spinners.
Those who work in ports or on the water have a good view of the proceedings; tugs may have the best view of all. These photos get you closer to ships than most people will ever be.
“The sides of ships have their own sort of beauty,” says photographer David Webster Smith, who is also a San Francisco tugboat engineer. “As soon as I can, I get my camera out.”
Most ships have clues to their identity emblazoned on their stern, often in the same order: owner, name, port (or “flag”), and International Maritime Organization (IMO) number. American President Lines (APL) owns this ship, christened the Mexico City, and it sails under the flag of Singapore.
The owner, name, and flag may change over a ship’s lifespan, but the IMO number stays the same as mandated by an international maritime treaty. Like vehicle identification numbers, IMOs help thwart fraud. Do a web search on an IMO number and the ship’s full history pops up.
Curious about those yellow-green, fortune-cookie-shaped objects along the lines? They’re anti-rat devices, foiling rodent attempts to scrabble from dock to line to ship.
Why would a ship owned by a South Korean company (Hanjin) list its port as Panama?
More than 70 percent of the world’s commercial ships sail under what’s called a “flag of convenience.” This means that the ship is registered in a foreign country and sails under that country’s flag, usually to reduce operating costs, sidestep taxes, or avoid the stricter safety standards of the owner’s country.
By far the most popular flag of convenience is Panama, with Liberia and the Marshall Islands fast gaining ground. For these countries, the fees companies pay to fly their flags are a significant source of revenue.
There’s another thing about this ship worth mentioning. See the crew members up on deck, at the far left and right of the photo? They’re actually dummies dressed as mariners, meant to fool pirates into thinking someone is always on watch.
These marks, called load lines, show the maximum load a ship can carry.
Load lines owe much to a British member of Parliament named Samuel Plimsoll. Worried about the loss of ships and crew members due to overloading, he sponsored a bill in 1876 that made it mandatory to have marks on both sides of a ship. If a ship is overloaded, the marks disappear underwater. The original “Plimsoll line” was a circle with a horizontal line through it. The symbol spread around the world; additional marks were added over the years.
The letters on either side of the circle stand for the ship’s registration authority. AB is the American Bureau of Shipping, one of 12 members of the International Association of Classification Societies, which sets and maintains safety standards for more than 90 percent of the world’s cargo ships.
The marks and letters to the right of the circle indicate maximum loads under different climatic conditions. Salt water is denser than fresh, cold water denser than warm. Since water density affects ship buoyancy, different conditions call for different load lines.
W marks the maximum load in winter temperate seawater, S in summer temperate seawater, T in tropical seawater, F in fresh water, and TF in tropical fresh water, like that of the Amazon River.
This ship is equipped with what’s called a bulbous bow, a protrusion low on the bow. Contrary to its ungainly appearance, the bulb actually reduces drag, increasing speed and fuel efficiency.
The white symbol that looks like the numeral five without the top line alerts tugboats to the presence of the bulb, which under certain conditions may be entirely underwater. Tugs need to be aware of the protuberance to avoid running it over as they maneuver around the ship, possibly damaging both the bulb and the tug.
The white circle with an X inside signals the presence of a bow thruster, a propulsion device that helps the boat maneuver sideways, a boon for getting on and off docks.
The numbers arranged in a vertical line—called draft marks—measure the distance between the bottom of the hull (the keel) and the waterline. If the water comes up to the 10-meter line, for example, that means 10 meters of the ship is underwater.
Where the water hits the draft lines tells sailors if the ship is overloaded, and—when compared to the reading on the opposite side of the boat—if it’s listing to one side.
To the left of the draft lines are different versions of the bulbous bow and bow thruster symbols. BT|FP tells you the position of the bow thruster: between the ballast tank (BT) and the forepeak (FP), the forward most part of the ship. It’s important for a tugboat operator to know the location of the bow thruster, as it creates turbulence that the tug would rather avoid.
Next
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Not many people have an opportunity to get this close to a container ship. Those who do may see icons that impart important information. For example, those black brackets to the right of the company name indicate where the tugboat is supposed to push. Photo by David Webster Smith
The Secret Language of Ships
Signs and symbols on the sides of ships tell stories about an industry few outsiders understand.
Credits
Text by Erin Van Rheenen
Photos by David Webster Smith
April 10, 2018 | 1,700 words, about 8 minutes
Approaching the container ship in San Francisco Bay, the tugboat looks like a pit bull puppy chasing an eighteen-wheeler. When the vessels are an arm’s length apart, the ship’s mate throws down a line. Now leashed to the ship, the tug can push and pull it around the bay. Big ships can’t easily slow down or maneuver by themselves—they’re meant for going in a straight line.
Tugboat crews routinely encounter what few of us will ever see. They easily read a vessel’s size, shape, function, and features, while deciphering at a glance the mysterious numbers, letters, and symbols on a ship’s hull. To non-mariners, the markings look like hieroglyphs. For those in the know, they speak volumes about a particular ship and also about the shipping industry.
Oceangoing vessels carry over 80 percent of the world’s trade, with more than 90,000 merchant ships plying international waters. Tankers, bulk carriers, and container ships—the largest things on Earth that move—are by far the most important modes of transportation of our time. They convey billions of tonnes of goods every year, bringing us everything from cars to crude oil to containers jammed with fidget spinners.
Those who work in ports or on the water have a good view of the proceedings; tugs may have the best view of all. These photos get you closer to ships than most people will ever be.
“The sides of ships have their own sort of beauty,” says photographer David Webster Smith, who is also a San Francisco tugboat engineer. “As soon as I can, I get my camera out.”
Most ships have clues to their identity emblazoned on their stern, often in the same order: owner, name, port (or “flag”), and International Maritime Organization (IMO) number. American President Lines (APL) owns this ship, christened the Mexico City, and it sails under the flag of Singapore.
The owner, name, and flag may change over a ship’s lifespan, but the IMO number stays the same as mandated by an international maritime treaty. Like vehicle identification numbers, IMOs help thwart fraud. Do a web search on an IMO number and the ship’s full history pops up.
Curious about those yellow-green, fortune-cookie-shaped objects along the lines? They’re anti-rat devices, foiling rodent attempts to scrabble from dock to line to ship.
Why would a ship owned by a South Korean company (Hanjin) list its port as Panama?
More than 70 percent of the world’s commercial ships sail under what’s called a “flag of convenience.” This means that the ship is registered in a foreign country and sails under that country’s flag, usually to reduce operating costs, sidestep taxes, or avoid the stricter safety standards of the owner’s country.
By far the most popular flag of convenience is Panama, with Liberia and the Marshall Islands fast gaining ground. For these countries, the fees companies pay to fly their flags are a significant source of revenue.
There’s another thing about this ship worth mentioning. See the crew members up on deck, at the far left and right of the photo? They’re actually dummies dressed as mariners, meant to fool pirates into thinking someone is always on watch.
These marks, called load lines, show the maximum load a ship can carry.
Load lines owe much to a British member of Parliament named Samuel Plimsoll. Worried about the loss of ships and crew members due to overloading, he sponsored a bill in 1876 that made it mandatory to have marks on both sides of a ship. If a ship is overloaded, the marks disappear underwater. The original “Plimsoll line” was a circle with a horizontal line through it. The symbol spread around the world; additional marks were added over the years.
The letters on either side of the circle stand for the ship’s registration authority. AB is the American Bureau of Shipping, one of 12 members of the International Association of Classification Societies, which sets and maintains safety standards for more than 90 percent of the world’s cargo ships.
The marks and letters to the right of the circle indicate maximum loads under different climatic conditions. Salt water is denser than fresh, cold water denser than warm. Since water density affects ship buoyancy, different conditions call for different load lines.
W marks the maximum load in winter temperate seawater, S in summer temperate seawater, T in tropical seawater, F in fresh water, and TF in tropical fresh water, like that of the Amazon River.
This ship is equipped with what’s called a bulbous bow, a protrusion low on the bow. Contrary to its ungainly appearance, the bulb actually reduces drag, increasing speed and fuel efficiency.
The white symbol that looks like the numeral five without the top line alerts tugboats to the presence of the bulb, which under certain conditions may be entirely underwater. Tugs need to be aware of the protuberance to avoid running it over as they maneuver around the ship, possibly damaging both the bulb and the tug.
The white circle with an X inside signals the presence of a bow thruster, a propulsion device that helps the boat maneuver sideways, a boon for getting on and off docks.
The numbers arranged in a vertical line—called draft marks—measure the distance between the bottom of the hull (the keel) and the waterline. If the water comes up to the 10-meter line, for example, that means 10 meters of the ship is underwater.
Where the water hits the draft lines tells sailors if the ship is overloaded, and—when compared to the reading on the opposite side of the boat—if it’s listing to one side.
To the left of the draft lines are different versions of the bulbous bow and bow thruster symbols. BT|FP tells you the position of the bow thruster: between the ballast tank (BT) and the forepeak (FP), the forward most part of the ship. It’s important for a tugboat operator to know the location of the bow thruster, as it creates turbulence that the tug would rather avoid.
Next
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Thanks, Sir Peanut! 
