What features would a pirate ship need to be able to support the weight of a dragon and cargo?

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A notable character in my story is a notorious pirate known for his ruthlessness. His notoriety makes him a target for other pirates, marine soldiers, and whatever else decided to make a home in the unforgiving depths of the sea. To protect himself, he’s come in the good graces on a metal dragon who, in exchange for a constant supply of precious metals and ores to eat, will use the radiance of its scales to blind, disable, or confuse an enemy.
However, making this plausible has become rather difficult for me. Dragons, naturally, way much much more than the common human and assorted cargo and boats can only handle so much weight before it sinks. So my question is: what characteristics or features would the ship need in order to handle the weight of the metal dragon? The answer can include what the ship is made of, how big it is, etc.



Details about the dragon for context:



  • The dragon survives on a diet of precious gems and ore, which makes it much heavier than other dragons.

  • It is so heavy that it cannot fly on it’s own

  • It is about 7 meters tall

  • It’s approximate weight is 28,000 pounds, or 14 tons

Guidelines:



  • The boat has to at least be able to carry 10,000 pounds

  • The dragon does not have to be able to stand up or move freely

  • The dragon can be confined to a single part of the ship





magic dragons







share|improve this question



















  • 1




    Just a note. A small medieval small ship would have a capacity of about 50 tons cargo. Even in the bronze age Ulysses likely had a ship which would easily carry a puny 14 tons dragon.
    – AlexP
    5 hours ago










  • Just for fun, to give a modern number to AlexP's historical ones, a modern cargo ship has no problem clearing 100,000 tons DWT. Ships are big!
    – Cort Ammon
    5 hours ago






  • 2




    @AlexP ... You can't put a 14 ton dragon at or above the metacenter of a small ship! If the metacentric height goes to zero, the ship's righting moment will be reversed; that is, any roll whatsoever will cause the ship to flip.
    – kingledion
    5 hours ago










  • Weight is not the issue. A @kingledion noted, it's size (not only height, which would cause the ship to roll over, but even if it lay down, it would be too long; not enough room to fit).
    – RonJohn
    5 hours ago










  • @kingledion: You can if you balance the ship judiciously, by adding ballast for example. I don't imagine that at any time in history mariners didn't know how to balance their ships. (Successful mariners, at least.)
    – AlexP
    4 hours ago















up vote
5
down vote

favorite
1












A notable character in my story is a notorious pirate known for his ruthlessness. His notoriety makes him a target for other pirates, marine soldiers, and whatever else decided to make a home in the unforgiving depths of the sea. To protect himself, he’s come in the good graces on a metal dragon who, in exchange for a constant supply of precious metals and ores to eat, will use the radiance of its scales to blind, disable, or confuse an enemy.
However, making this plausible has become rather difficult for me. Dragons, naturally, way much much more than the common human and assorted cargo and boats can only handle so much weight before it sinks. So my question is: what characteristics or features would the ship need in order to handle the weight of the metal dragon? The answer can include what the ship is made of, how big it is, etc.



Details about the dragon for context:



  • The dragon survives on a diet of precious gems and ore, which makes it much heavier than other dragons.

  • It is so heavy that it cannot fly on it’s own

  • It is about 7 meters tall

  • It’s approximate weight is 28,000 pounds, or 14 tons

Guidelines:



  • The boat has to at least be able to carry 10,000 pounds

  • The dragon does not have to be able to stand up or move freely

  • The dragon can be confined to a single part of the ship





magic dragons







share|improve this question



















  • 1




    Just a note. A small medieval small ship would have a capacity of about 50 tons cargo. Even in the bronze age Ulysses likely had a ship which would easily carry a puny 14 tons dragon.
    – AlexP
    5 hours ago










  • Just for fun, to give a modern number to AlexP's historical ones, a modern cargo ship has no problem clearing 100,000 tons DWT. Ships are big!
    – Cort Ammon
    5 hours ago






  • 2




    @AlexP ... You can't put a 14 ton dragon at or above the metacenter of a small ship! If the metacentric height goes to zero, the ship's righting moment will be reversed; that is, any roll whatsoever will cause the ship to flip.
    – kingledion
    5 hours ago










  • Weight is not the issue. A @kingledion noted, it's size (not only height, which would cause the ship to roll over, but even if it lay down, it would be too long; not enough room to fit).
    – RonJohn
    5 hours ago










  • @kingledion: You can if you balance the ship judiciously, by adding ballast for example. I don't imagine that at any time in history mariners didn't know how to balance their ships. (Successful mariners, at least.)
    – AlexP
    4 hours ago













up vote
5
down vote

favorite
1









up vote
5
down vote

favorite
1






1





A notable character in my story is a notorious pirate known for his ruthlessness. His notoriety makes him a target for other pirates, marine soldiers, and whatever else decided to make a home in the unforgiving depths of the sea. To protect himself, he’s come in the good graces on a metal dragon who, in exchange for a constant supply of precious metals and ores to eat, will use the radiance of its scales to blind, disable, or confuse an enemy.
However, making this plausible has become rather difficult for me. Dragons, naturally, way much much more than the common human and assorted cargo and boats can only handle so much weight before it sinks. So my question is: what characteristics or features would the ship need in order to handle the weight of the metal dragon? The answer can include what the ship is made of, how big it is, etc.



Details about the dragon for context:



  • The dragon survives on a diet of precious gems and ore, which makes it much heavier than other dragons.

  • It is so heavy that it cannot fly on it’s own

  • It is about 7 meters tall

  • It’s approximate weight is 28,000 pounds, or 14 tons

Guidelines:



  • The boat has to at least be able to carry 10,000 pounds

  • The dragon does not have to be able to stand up or move freely

  • The dragon can be confined to a single part of the ship





magic dragons







share|improve this question















A notable character in my story is a notorious pirate known for his ruthlessness. His notoriety makes him a target for other pirates, marine soldiers, and whatever else decided to make a home in the unforgiving depths of the sea. To protect himself, he’s come in the good graces on a metal dragon who, in exchange for a constant supply of precious metals and ores to eat, will use the radiance of its scales to blind, disable, or confuse an enemy.
However, making this plausible has become rather difficult for me. Dragons, naturally, way much much more than the common human and assorted cargo and boats can only handle so much weight before it sinks. So my question is: what characteristics or features would the ship need in order to handle the weight of the metal dragon? The answer can include what the ship is made of, how big it is, etc.



Details about the dragon for context:



  • The dragon survives on a diet of precious gems and ore, which makes it much heavier than other dragons.

  • It is so heavy that it cannot fly on it’s own

  • It is about 7 meters tall

  • It’s approximate weight is 28,000 pounds, or 14 tons

Guidelines:



  • The boat has to at least be able to carry 10,000 pounds

  • The dragon does not have to be able to stand up or move freely

  • The dragon can be confined to a single part of the ship





magic dragons




magic dragons






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 4 hours ago









kingledion

65k22205359




65k22205359










asked 5 hours ago









Mop

3017




3017







  • 1




    Just a note. A small medieval small ship would have a capacity of about 50 tons cargo. Even in the bronze age Ulysses likely had a ship which would easily carry a puny 14 tons dragon.
    – AlexP
    5 hours ago










  • Just for fun, to give a modern number to AlexP's historical ones, a modern cargo ship has no problem clearing 100,000 tons DWT. Ships are big!
    – Cort Ammon
    5 hours ago






  • 2




    @AlexP ... You can't put a 14 ton dragon at or above the metacenter of a small ship! If the metacentric height goes to zero, the ship's righting moment will be reversed; that is, any roll whatsoever will cause the ship to flip.
    – kingledion
    5 hours ago










  • Weight is not the issue. A @kingledion noted, it's size (not only height, which would cause the ship to roll over, but even if it lay down, it would be too long; not enough room to fit).
    – RonJohn
    5 hours ago










  • @kingledion: You can if you balance the ship judiciously, by adding ballast for example. I don't imagine that at any time in history mariners didn't know how to balance their ships. (Successful mariners, at least.)
    – AlexP
    4 hours ago













  • 1




    Just a note. A small medieval small ship would have a capacity of about 50 tons cargo. Even in the bronze age Ulysses likely had a ship which would easily carry a puny 14 tons dragon.
    – AlexP
    5 hours ago










  • Just for fun, to give a modern number to AlexP's historical ones, a modern cargo ship has no problem clearing 100,000 tons DWT. Ships are big!
    – Cort Ammon
    5 hours ago






  • 2




    @AlexP ... You can't put a 14 ton dragon at or above the metacenter of a small ship! If the metacentric height goes to zero, the ship's righting moment will be reversed; that is, any roll whatsoever will cause the ship to flip.
    – kingledion
    5 hours ago










  • Weight is not the issue. A @kingledion noted, it's size (not only height, which would cause the ship to roll over, but even if it lay down, it would be too long; not enough room to fit).
    – RonJohn
    5 hours ago










  • @kingledion: You can if you balance the ship judiciously, by adding ballast for example. I don't imagine that at any time in history mariners didn't know how to balance their ships. (Successful mariners, at least.)
    – AlexP
    4 hours ago








1




1




Just a note. A small medieval small ship would have a capacity of about 50 tons cargo. Even in the bronze age Ulysses likely had a ship which would easily carry a puny 14 tons dragon.
– AlexP
5 hours ago




Just a note. A small medieval small ship would have a capacity of about 50 tons cargo. Even in the bronze age Ulysses likely had a ship which would easily carry a puny 14 tons dragon.
– AlexP
5 hours ago












Just for fun, to give a modern number to AlexP's historical ones, a modern cargo ship has no problem clearing 100,000 tons DWT. Ships are big!
– Cort Ammon
5 hours ago




Just for fun, to give a modern number to AlexP's historical ones, a modern cargo ship has no problem clearing 100,000 tons DWT. Ships are big!
– Cort Ammon
5 hours ago




2




2




@AlexP ... You can't put a 14 ton dragon at or above the metacenter of a small ship! If the metacentric height goes to zero, the ship's righting moment will be reversed; that is, any roll whatsoever will cause the ship to flip.
– kingledion
5 hours ago




@AlexP ... You can't put a 14 ton dragon at or above the metacenter of a small ship! If the metacentric height goes to zero, the ship's righting moment will be reversed; that is, any roll whatsoever will cause the ship to flip.
– kingledion
5 hours ago












Weight is not the issue. A @kingledion noted, it's size (not only height, which would cause the ship to roll over, but even if it lay down, it would be too long; not enough room to fit).
– RonJohn
5 hours ago




Weight is not the issue. A @kingledion noted, it's size (not only height, which would cause the ship to roll over, but even if it lay down, it would be too long; not enough room to fit).
– RonJohn
5 hours ago












@kingledion: You can if you balance the ship judiciously, by adding ballast for example. I don't imagine that at any time in history mariners didn't know how to balance their ships. (Successful mariners, at least.)
– AlexP
4 hours ago





@kingledion: You can if you balance the ship judiciously, by adding ballast for example. I don't imagine that at any time in history mariners didn't know how to balance their ships. (Successful mariners, at least.)
– AlexP
4 hours ago











2 Answers
2






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up vote
4
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Size alone



This is a buoyancy problem and is solved through naval architecture. Here are the key concepts:



enter image description here



The center of gravity is the center of mass on the ship. The ship is pulled downwards as if it were a point mass at this point. The center of buoyancy is 'point source' of the buoyancy. These are two forces acting on a ship. When the ship is upright (the picture to the left, above) these two forces cancel each other out.



When the ship rolls to one side or another they are out of balance. If you look at the picture to the right, above, the center of buoyancy is to the left of the center of gravity. That means these two forces will cause the ship to 'twist' in a counter-clockwise direction. This will cause the ship to right itself--this is called righting moment.



enter image description here



In this picture above, the righting arm is positive; that is the righting moment acts in the direction that will right the ship. It is possible, however, to have a negative righting arm. In that case, G will be to the right of Z (and B) in the above picture, and the ship will flip.



The last concept that is important is the metacenter (M in the above diagrams). As the ship rolls from left to right, the center of buoyancy will rotate around the axis of the metacenter. The metacentric height is the (constant) distance between G and M.



If you mount a heavy dragon on the deck, then this move the center of gravity towards the deck of the ship. As G moves upwards, if it ever raises past M then the ship becomes unstable, as any perturbation will move G to the right of B and flip the ship.



What happens to a small ship?



If your your pirate is master of a galley crew (or fleet), then he is likely going to be out of luck as far as landing a dragon. Here is a diagram of a trireme, based on what the Greeks would have used at Salamis. This is a ~50 ton vessel, with a crew of 100-200. Venetian galleys of the 14th century were not much bigger; warships were perhaps 100 tons and merchant galleys up to 300.



enter image description here



For this ship, the buoyant force is 50 tons (same as ship's displacement) and metacentric height is only about one meter. When the ship heels over 20 degrees, the righting moment is the buoyancy times the righting arm; which is



$$ GM cdot sin(theta_r)$$ for shallow angles of $theta_r$, or roll angle. GM is the metacentric height. Righting arm in this case is about 35 cm. The righting moment is then about 175 kN-m. This is the force that buoyancy puts on the boat to counteract wind and wave and keep you from tipping.



If a dragon is about 14,000 kg, and is two meters above the center of gravity, this changes the center of gravity upwards by roughly 0.4 meters relative to the metacenter. This has a linear reduction of righting arm down to 100 kN-m. This is a pretty solid hit on the stability; almost a 50% drop. Triremes did flip in storms; now they take about half the force to flip with the dragon on board.



How big should the ship be?



The ship should be much larger than the dragon. How much larger depends on the design of the ship. Where the trireme is a long, low ship, with only 2 meters of freeboard (height of the deck above the water level). This is the same freeboard as the reconstructed Nina (of Columbus fame) had at only 40 tons. A larger sailing ship would have a greater height out of the water, therefore a dragon posses a proportionately larger problem.



I would estimate that for a galley-stype ship, you would want at least a 200 ton vessel to safely park a dragon. On a full masted, Pirates of the Carribean stype sailing ship, you probably want more like 500 tons. This isn't that big in the scheme of things, but it is significantly larger than Queen Anne's Revenge (Blackbeard's ship). It is, however, much smaller than USS Constitution at 2200 tons. So, your pirate is going to need a relatively large ship.



On the other hand, the dragon can do a lot to help. First, the dragon has to keep its center of gravity in the center of the boat (just like you have to be careful in a canoe). Second, it would be really nice if the dragon left whenever the wind and waves go high. The danger of flipping is pretty small in calm seas.






share|improve this answer






















  • Triremes (and galleys in general) were not cargo ships, and were never used as such.
    – AlexP
    4 hours ago











  • @AlexP But they were pirate ships, which is the point of this question.
    – kingledion
    1 hour ago

















up vote
0
down vote













14 tons dragon + 10.000 pounds of cargo equals roughly 20 tons in total.



Pirate ships like those used in the 18th century on Earth could easily carry such weight and more.



The Queen Anne's Revenge, for example, had a cargo capacity of about 200 tons.



The San Esteban, a Spanish Galleon shipwrecked in the Gulf of Mexico, is estimated to have been able to carry between 167 tons to 291 tons of cargo.



So, the weight itself wouldn't be a problem, it weight distribution that would be. The dragon would have to mostly keep close to the center line of the vessel to avoid creating an imbalance.






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  • 1




    Please expand this answer with quotes from sources. Otherwise it might get deleted. (Already it's been downvoted.)
    – RonJohn
    5 hours ago










  • @RonJohn: The Queen Anne's Revenge and the San Esteban are pretty famous ships. I have added hyperlinks to their Wikipedia articles.
    – AlexP
    4 hours ago










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2 Answers
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active

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2 Answers
2






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
4
down vote













Size alone



This is a buoyancy problem and is solved through naval architecture. Here are the key concepts:



enter image description here



The center of gravity is the center of mass on the ship. The ship is pulled downwards as if it were a point mass at this point. The center of buoyancy is 'point source' of the buoyancy. These are two forces acting on a ship. When the ship is upright (the picture to the left, above) these two forces cancel each other out.



When the ship rolls to one side or another they are out of balance. If you look at the picture to the right, above, the center of buoyancy is to the left of the center of gravity. That means these two forces will cause the ship to 'twist' in a counter-clockwise direction. This will cause the ship to right itself--this is called righting moment.



enter image description here



In this picture above, the righting arm is positive; that is the righting moment acts in the direction that will right the ship. It is possible, however, to have a negative righting arm. In that case, G will be to the right of Z (and B) in the above picture, and the ship will flip.



The last concept that is important is the metacenter (M in the above diagrams). As the ship rolls from left to right, the center of buoyancy will rotate around the axis of the metacenter. The metacentric height is the (constant) distance between G and M.



If you mount a heavy dragon on the deck, then this move the center of gravity towards the deck of the ship. As G moves upwards, if it ever raises past M then the ship becomes unstable, as any perturbation will move G to the right of B and flip the ship.



What happens to a small ship?



If your your pirate is master of a galley crew (or fleet), then he is likely going to be out of luck as far as landing a dragon. Here is a diagram of a trireme, based on what the Greeks would have used at Salamis. This is a ~50 ton vessel, with a crew of 100-200. Venetian galleys of the 14th century were not much bigger; warships were perhaps 100 tons and merchant galleys up to 300.



enter image description here



For this ship, the buoyant force is 50 tons (same as ship's displacement) and metacentric height is only about one meter. When the ship heels over 20 degrees, the righting moment is the buoyancy times the righting arm; which is



$$ GM cdot sin(theta_r)$$ for shallow angles of $theta_r$, or roll angle. GM is the metacentric height. Righting arm in this case is about 35 cm. The righting moment is then about 175 kN-m. This is the force that buoyancy puts on the boat to counteract wind and wave and keep you from tipping.



If a dragon is about 14,000 kg, and is two meters above the center of gravity, this changes the center of gravity upwards by roughly 0.4 meters relative to the metacenter. This has a linear reduction of righting arm down to 100 kN-m. This is a pretty solid hit on the stability; almost a 50% drop. Triremes did flip in storms; now they take about half the force to flip with the dragon on board.



How big should the ship be?



The ship should be much larger than the dragon. How much larger depends on the design of the ship. Where the trireme is a long, low ship, with only 2 meters of freeboard (height of the deck above the water level). This is the same freeboard as the reconstructed Nina (of Columbus fame) had at only 40 tons. A larger sailing ship would have a greater height out of the water, therefore a dragon posses a proportionately larger problem.



I would estimate that for a galley-stype ship, you would want at least a 200 ton vessel to safely park a dragon. On a full masted, Pirates of the Carribean stype sailing ship, you probably want more like 500 tons. This isn't that big in the scheme of things, but it is significantly larger than Queen Anne's Revenge (Blackbeard's ship). It is, however, much smaller than USS Constitution at 2200 tons. So, your pirate is going to need a relatively large ship.



On the other hand, the dragon can do a lot to help. First, the dragon has to keep its center of gravity in the center of the boat (just like you have to be careful in a canoe). Second, it would be really nice if the dragon left whenever the wind and waves go high. The danger of flipping is pretty small in calm seas.






share|improve this answer






















  • Triremes (and galleys in general) were not cargo ships, and were never used as such.
    – AlexP
    4 hours ago











  • @AlexP But they were pirate ships, which is the point of this question.
    – kingledion
    1 hour ago














up vote
4
down vote













Size alone



This is a buoyancy problem and is solved through naval architecture. Here are the key concepts:



enter image description here



The center of gravity is the center of mass on the ship. The ship is pulled downwards as if it were a point mass at this point. The center of buoyancy is 'point source' of the buoyancy. These are two forces acting on a ship. When the ship is upright (the picture to the left, above) these two forces cancel each other out.



When the ship rolls to one side or another they are out of balance. If you look at the picture to the right, above, the center of buoyancy is to the left of the center of gravity. That means these two forces will cause the ship to 'twist' in a counter-clockwise direction. This will cause the ship to right itself--this is called righting moment.



enter image description here



In this picture above, the righting arm is positive; that is the righting moment acts in the direction that will right the ship. It is possible, however, to have a negative righting arm. In that case, G will be to the right of Z (and B) in the above picture, and the ship will flip.



The last concept that is important is the metacenter (M in the above diagrams). As the ship rolls from left to right, the center of buoyancy will rotate around the axis of the metacenter. The metacentric height is the (constant) distance between G and M.



If you mount a heavy dragon on the deck, then this move the center of gravity towards the deck of the ship. As G moves upwards, if it ever raises past M then the ship becomes unstable, as any perturbation will move G to the right of B and flip the ship.



What happens to a small ship?



If your your pirate is master of a galley crew (or fleet), then he is likely going to be out of luck as far as landing a dragon. Here is a diagram of a trireme, based on what the Greeks would have used at Salamis. This is a ~50 ton vessel, with a crew of 100-200. Venetian galleys of the 14th century were not much bigger; warships were perhaps 100 tons and merchant galleys up to 300.



enter image description here



For this ship, the buoyant force is 50 tons (same as ship's displacement) and metacentric height is only about one meter. When the ship heels over 20 degrees, the righting moment is the buoyancy times the righting arm; which is



$$ GM cdot sin(theta_r)$$ for shallow angles of $theta_r$, or roll angle. GM is the metacentric height. Righting arm in this case is about 35 cm. The righting moment is then about 175 kN-m. This is the force that buoyancy puts on the boat to counteract wind and wave and keep you from tipping.



If a dragon is about 14,000 kg, and is two meters above the center of gravity, this changes the center of gravity upwards by roughly 0.4 meters relative to the metacenter. This has a linear reduction of righting arm down to 100 kN-m. This is a pretty solid hit on the stability; almost a 50% drop. Triremes did flip in storms; now they take about half the force to flip with the dragon on board.



How big should the ship be?



The ship should be much larger than the dragon. How much larger depends on the design of the ship. Where the trireme is a long, low ship, with only 2 meters of freeboard (height of the deck above the water level). This is the same freeboard as the reconstructed Nina (of Columbus fame) had at only 40 tons. A larger sailing ship would have a greater height out of the water, therefore a dragon posses a proportionately larger problem.



I would estimate that for a galley-stype ship, you would want at least a 200 ton vessel to safely park a dragon. On a full masted, Pirates of the Carribean stype sailing ship, you probably want more like 500 tons. This isn't that big in the scheme of things, but it is significantly larger than Queen Anne's Revenge (Blackbeard's ship). It is, however, much smaller than USS Constitution at 2200 tons. So, your pirate is going to need a relatively large ship.



On the other hand, the dragon can do a lot to help. First, the dragon has to keep its center of gravity in the center of the boat (just like you have to be careful in a canoe). Second, it would be really nice if the dragon left whenever the wind and waves go high. The danger of flipping is pretty small in calm seas.






share|improve this answer






















  • Triremes (and galleys in general) were not cargo ships, and were never used as such.
    – AlexP
    4 hours ago











  • @AlexP But they were pirate ships, which is the point of this question.
    – kingledion
    1 hour ago












up vote
4
down vote










up vote
4
down vote









Size alone



This is a buoyancy problem and is solved through naval architecture. Here are the key concepts:



enter image description here



The center of gravity is the center of mass on the ship. The ship is pulled downwards as if it were a point mass at this point. The center of buoyancy is 'point source' of the buoyancy. These are two forces acting on a ship. When the ship is upright (the picture to the left, above) these two forces cancel each other out.



When the ship rolls to one side or another they are out of balance. If you look at the picture to the right, above, the center of buoyancy is to the left of the center of gravity. That means these two forces will cause the ship to 'twist' in a counter-clockwise direction. This will cause the ship to right itself--this is called righting moment.



enter image description here



In this picture above, the righting arm is positive; that is the righting moment acts in the direction that will right the ship. It is possible, however, to have a negative righting arm. In that case, G will be to the right of Z (and B) in the above picture, and the ship will flip.



The last concept that is important is the metacenter (M in the above diagrams). As the ship rolls from left to right, the center of buoyancy will rotate around the axis of the metacenter. The metacentric height is the (constant) distance between G and M.



If you mount a heavy dragon on the deck, then this move the center of gravity towards the deck of the ship. As G moves upwards, if it ever raises past M then the ship becomes unstable, as any perturbation will move G to the right of B and flip the ship.



What happens to a small ship?



If your your pirate is master of a galley crew (or fleet), then he is likely going to be out of luck as far as landing a dragon. Here is a diagram of a trireme, based on what the Greeks would have used at Salamis. This is a ~50 ton vessel, with a crew of 100-200. Venetian galleys of the 14th century were not much bigger; warships were perhaps 100 tons and merchant galleys up to 300.



enter image description here



For this ship, the buoyant force is 50 tons (same as ship's displacement) and metacentric height is only about one meter. When the ship heels over 20 degrees, the righting moment is the buoyancy times the righting arm; which is



$$ GM cdot sin(theta_r)$$ for shallow angles of $theta_r$, or roll angle. GM is the metacentric height. Righting arm in this case is about 35 cm. The righting moment is then about 175 kN-m. This is the force that buoyancy puts on the boat to counteract wind and wave and keep you from tipping.



If a dragon is about 14,000 kg, and is two meters above the center of gravity, this changes the center of gravity upwards by roughly 0.4 meters relative to the metacenter. This has a linear reduction of righting arm down to 100 kN-m. This is a pretty solid hit on the stability; almost a 50% drop. Triremes did flip in storms; now they take about half the force to flip with the dragon on board.



How big should the ship be?



The ship should be much larger than the dragon. How much larger depends on the design of the ship. Where the trireme is a long, low ship, with only 2 meters of freeboard (height of the deck above the water level). This is the same freeboard as the reconstructed Nina (of Columbus fame) had at only 40 tons. A larger sailing ship would have a greater height out of the water, therefore a dragon posses a proportionately larger problem.



I would estimate that for a galley-stype ship, you would want at least a 200 ton vessel to safely park a dragon. On a full masted, Pirates of the Carribean stype sailing ship, you probably want more like 500 tons. This isn't that big in the scheme of things, but it is significantly larger than Queen Anne's Revenge (Blackbeard's ship). It is, however, much smaller than USS Constitution at 2200 tons. So, your pirate is going to need a relatively large ship.



On the other hand, the dragon can do a lot to help. First, the dragon has to keep its center of gravity in the center of the boat (just like you have to be careful in a canoe). Second, it would be really nice if the dragon left whenever the wind and waves go high. The danger of flipping is pretty small in calm seas.






share|improve this answer














Size alone



This is a buoyancy problem and is solved through naval architecture. Here are the key concepts:



enter image description here



The center of gravity is the center of mass on the ship. The ship is pulled downwards as if it were a point mass at this point. The center of buoyancy is 'point source' of the buoyancy. These are two forces acting on a ship. When the ship is upright (the picture to the left, above) these two forces cancel each other out.



When the ship rolls to one side or another they are out of balance. If you look at the picture to the right, above, the center of buoyancy is to the left of the center of gravity. That means these two forces will cause the ship to 'twist' in a counter-clockwise direction. This will cause the ship to right itself--this is called righting moment.



enter image description here



In this picture above, the righting arm is positive; that is the righting moment acts in the direction that will right the ship. It is possible, however, to have a negative righting arm. In that case, G will be to the right of Z (and B) in the above picture, and the ship will flip.



The last concept that is important is the metacenter (M in the above diagrams). As the ship rolls from left to right, the center of buoyancy will rotate around the axis of the metacenter. The metacentric height is the (constant) distance between G and M.



If you mount a heavy dragon on the deck, then this move the center of gravity towards the deck of the ship. As G moves upwards, if it ever raises past M then the ship becomes unstable, as any perturbation will move G to the right of B and flip the ship.



What happens to a small ship?



If your your pirate is master of a galley crew (or fleet), then he is likely going to be out of luck as far as landing a dragon. Here is a diagram of a trireme, based on what the Greeks would have used at Salamis. This is a ~50 ton vessel, with a crew of 100-200. Venetian galleys of the 14th century were not much bigger; warships were perhaps 100 tons and merchant galleys up to 300.



enter image description here



For this ship, the buoyant force is 50 tons (same as ship's displacement) and metacentric height is only about one meter. When the ship heels over 20 degrees, the righting moment is the buoyancy times the righting arm; which is



$$ GM cdot sin(theta_r)$$ for shallow angles of $theta_r$, or roll angle. GM is the metacentric height. Righting arm in this case is about 35 cm. The righting moment is then about 175 kN-m. This is the force that buoyancy puts on the boat to counteract wind and wave and keep you from tipping.



If a dragon is about 14,000 kg, and is two meters above the center of gravity, this changes the center of gravity upwards by roughly 0.4 meters relative to the metacenter. This has a linear reduction of righting arm down to 100 kN-m. This is a pretty solid hit on the stability; almost a 50% drop. Triremes did flip in storms; now they take about half the force to flip with the dragon on board.



How big should the ship be?



The ship should be much larger than the dragon. How much larger depends on the design of the ship. Where the trireme is a long, low ship, with only 2 meters of freeboard (height of the deck above the water level). This is the same freeboard as the reconstructed Nina (of Columbus fame) had at only 40 tons. A larger sailing ship would have a greater height out of the water, therefore a dragon posses a proportionately larger problem.



I would estimate that for a galley-stype ship, you would want at least a 200 ton vessel to safely park a dragon. On a full masted, Pirates of the Carribean stype sailing ship, you probably want more like 500 tons. This isn't that big in the scheme of things, but it is significantly larger than Queen Anne's Revenge (Blackbeard's ship). It is, however, much smaller than USS Constitution at 2200 tons. So, your pirate is going to need a relatively large ship.



On the other hand, the dragon can do a lot to help. First, the dragon has to keep its center of gravity in the center of the boat (just like you have to be careful in a canoe). Second, it would be really nice if the dragon left whenever the wind and waves go high. The danger of flipping is pretty small in calm seas.







share|improve this answer














share|improve this answer



share|improve this answer








edited 4 hours ago

























answered 5 hours ago









kingledion

65k22205359




65k22205359











  • Triremes (and galleys in general) were not cargo ships, and were never used as such.
    – AlexP
    4 hours ago











  • @AlexP But they were pirate ships, which is the point of this question.
    – kingledion
    1 hour ago
















  • Triremes (and galleys in general) were not cargo ships, and were never used as such.
    – AlexP
    4 hours ago











  • @AlexP But they were pirate ships, which is the point of this question.
    – kingledion
    1 hour ago















Triremes (and galleys in general) were not cargo ships, and were never used as such.
– AlexP
4 hours ago





Triremes (and galleys in general) were not cargo ships, and were never used as such.
– AlexP
4 hours ago













@AlexP But they were pirate ships, which is the point of this question.
– kingledion
1 hour ago




@AlexP But they were pirate ships, which is the point of this question.
– kingledion
1 hour ago










up vote
0
down vote













14 tons dragon + 10.000 pounds of cargo equals roughly 20 tons in total.



Pirate ships like those used in the 18th century on Earth could easily carry such weight and more.



The Queen Anne's Revenge, for example, had a cargo capacity of about 200 tons.



The San Esteban, a Spanish Galleon shipwrecked in the Gulf of Mexico, is estimated to have been able to carry between 167 tons to 291 tons of cargo.



So, the weight itself wouldn't be a problem, it weight distribution that would be. The dragon would have to mostly keep close to the center line of the vessel to avoid creating an imbalance.






share|improve this answer










New contributor




Sava is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.













  • 1




    Please expand this answer with quotes from sources. Otherwise it might get deleted. (Already it's been downvoted.)
    – RonJohn
    5 hours ago










  • @RonJohn: The Queen Anne's Revenge and the San Esteban are pretty famous ships. I have added hyperlinks to their Wikipedia articles.
    – AlexP
    4 hours ago














up vote
0
down vote













14 tons dragon + 10.000 pounds of cargo equals roughly 20 tons in total.



Pirate ships like those used in the 18th century on Earth could easily carry such weight and more.



The Queen Anne's Revenge, for example, had a cargo capacity of about 200 tons.



The San Esteban, a Spanish Galleon shipwrecked in the Gulf of Mexico, is estimated to have been able to carry between 167 tons to 291 tons of cargo.



So, the weight itself wouldn't be a problem, it weight distribution that would be. The dragon would have to mostly keep close to the center line of the vessel to avoid creating an imbalance.






share|improve this answer










New contributor




Sava is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.













  • 1




    Please expand this answer with quotes from sources. Otherwise it might get deleted. (Already it's been downvoted.)
    – RonJohn
    5 hours ago










  • @RonJohn: The Queen Anne's Revenge and the San Esteban are pretty famous ships. I have added hyperlinks to their Wikipedia articles.
    – AlexP
    4 hours ago












up vote
0
down vote










up vote
0
down vote









14 tons dragon + 10.000 pounds of cargo equals roughly 20 tons in total.



Pirate ships like those used in the 18th century on Earth could easily carry such weight and more.



The Queen Anne's Revenge, for example, had a cargo capacity of about 200 tons.



The San Esteban, a Spanish Galleon shipwrecked in the Gulf of Mexico, is estimated to have been able to carry between 167 tons to 291 tons of cargo.



So, the weight itself wouldn't be a problem, it weight distribution that would be. The dragon would have to mostly keep close to the center line of the vessel to avoid creating an imbalance.






share|improve this answer










New contributor




Sava is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









14 tons dragon + 10.000 pounds of cargo equals roughly 20 tons in total.



Pirate ships like those used in the 18th century on Earth could easily carry such weight and more.



The Queen Anne's Revenge, for example, had a cargo capacity of about 200 tons.



The San Esteban, a Spanish Galleon shipwrecked in the Gulf of Mexico, is estimated to have been able to carry between 167 tons to 291 tons of cargo.



So, the weight itself wouldn't be a problem, it weight distribution that would be. The dragon would have to mostly keep close to the center line of the vessel to avoid creating an imbalance.







share|improve this answer










New contributor




Sava is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this answer



share|improve this answer








edited 4 hours ago









AlexP

32k773123




32k773123






New contributor




Sava is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









answered 5 hours ago









Sava

113




113




New contributor




Sava is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





Sava is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Sava is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







  • 1




    Please expand this answer with quotes from sources. Otherwise it might get deleted. (Already it's been downvoted.)
    – RonJohn
    5 hours ago










  • @RonJohn: The Queen Anne's Revenge and the San Esteban are pretty famous ships. I have added hyperlinks to their Wikipedia articles.
    – AlexP
    4 hours ago












  • 1




    Please expand this answer with quotes from sources. Otherwise it might get deleted. (Already it's been downvoted.)
    – RonJohn
    5 hours ago










  • @RonJohn: The Queen Anne's Revenge and the San Esteban are pretty famous ships. I have added hyperlinks to their Wikipedia articles.
    – AlexP
    4 hours ago







1




1




Please expand this answer with quotes from sources. Otherwise it might get deleted. (Already it's been downvoted.)
– RonJohn
5 hours ago




Please expand this answer with quotes from sources. Otherwise it might get deleted. (Already it's been downvoted.)
– RonJohn
5 hours ago












@RonJohn: The Queen Anne's Revenge and the San Esteban are pretty famous ships. I have added hyperlinks to their Wikipedia articles.
– AlexP
4 hours ago




@RonJohn: The Queen Anne's Revenge and the San Esteban are pretty famous ships. I have added hyperlinks to their Wikipedia articles.
– AlexP
4 hours ago

















 

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