Anchor from Blackbeard ship recovered

[KLA2]

A ton and a half. One of three!

Plus 40 cannons ... how did that ship stay afloat?

http://www.cnn.com/2011/US/05/27/north. ... tml?hpt=C1

I cannot easily find the specific stats, but I think ships of the day were 50 feet long, or so ... made largely of heavy wood like oak ...

[Мастер]

A ton and a half. One of three!

Plus 40 cannons ... how did that ship stay afloat?

http://www.cnn.com/2011/US/05/27/north. ... tml?hpt=C1

I cannot easily find the specific stats, but I think ships of the day were 50 feet long, or so ... made largely of heavy wood like oak ...

How much does the cannon weigh?

Assuming I'm doing this right, the density of iron is a bit over seven times the density of water. Taking the density of air to be close to zero, seems like a canon should take about seven times its volume to be empty (not counting the bored out part) in order not to contribute to the non-buoyancy of the ship.

Does that seem right?

[KLA2]

A ton and a half. One of three!

Plus 40 cannons ... how did that ship stay afloat?

http://www.cnn.com/2011/US/05/27/north. ... tml?hpt=C1

I cannot easily find the specific stats, but I think ships of the day were 50 feet long, or so ... made largely of heavy wood like oak ...

How much does the cannon weigh?

Assuming I'm doing this right, the density of iron is a bit over seven times the density of water. Taking the density of air to be close to zero, seems like a canon should take about seven times its volume to be empty (not counting the bored out part) in order not to contribute to the non-buoyancy of the ship.

Does that seem right?

Yes, about 7.68 to seawater.

But the hardwood of the ship itself, crew. cargo, plus supporting all the masts and superstructure ABOVE the waterline ... I don't know what I am talking about.

So much for this thread!

[Мастер]

But the hardwood of the ship itself, crew. cargo, plus supporting all the masts and superstructure ABOVE the waterline ...

Yea, I don't know how much that stuff weighs.

Does hardwood sink?

[KLA2]

But the hardwood of the ship itself, crew. cargo, plus supporting all the masts and superstructure ABOVE the waterline ...

Yea, I don't know how much that stuff weighs.

Does hardwood sink?

Well, not, accordingly to this analysis:

http://www.simetric.co.uk/si_wood.htm

My point was, like an iceberg, it may be lighter than water, but may not all float above the surface. :P

[KLA2]

A final shot over the bow:

We should consider the Vasa (Sweden, 1628) and The Mary Rose 1536 - 45:

The most recent surveys of the ship indicate that the ship was modified late in her career and has lent support to the idea that the Mary Rose was altered too much to be properly seaworthy. Marsden has suggested that the weight of additional heavy guns would have lowered her draught so much that the waterline was less than one metre (c. 3 feet) from the gunports on the main deck.

http://en.wikipedia.org/wiki/Mary_Rose# ... of_sinking

I am reminded of the haunting dialogue from “Titanic” where the architect (?) ISMAY says,

But this ship can't sink! And the builder, (?) ANDREWS says,

She is made of iron, sir. I assure you, she can. And she will. It is a
mathematical certainty.


I do not argue math and physics with you, Mactep. Properly built, loaded and sailed, no ship should sink under normal conditions. :)

[Мастер]

I do not argue math and physics with you, Mactep. Properly built, loaded and sailed, no ship should sink under normal conditions. :)

Not trying to argue or dispute anything, just exploring it a little bit!

I think even softwood doesn't float much above the surface, does it? If so, the buoyancy must come mostly from the air enclosed (missing anything here?). And then, just the air that is below the surface of the water :)

Must be an interesting engineering problem. Too bad we don't have anyone who's into construction of antique ships (or maybe we do?).

[Superluminal]

Water displacement?

[KLA2]

Relative density of the entire (averaged out) sealed volume, I would say. Which is why an iron ship floats, unless it springs a leak.

Which sums up what you both just said ... only I expressed it better. :P

[Мастер]

Relative density of the entire (averaged out) sealed volume, I would say. Which is why an iron ship floats, unless it springs a leak.

Which sums up what you both just said ... only I expressed it better. :P

I don't know. It is the weight of the entire ship - the structure, the contents, and the air, although that shouldn't be much, vs. the weight of the water that is displaced (which corresponds to only a part of the volume of the ship).

Is that what your answer says? (I'm confusing myself.)

[KLA2]

I thought so. I guess I did NOT express it better.

[tubeswell]

So - how did it sink again?

[Halcyon Dayz, FCD]

It's funny to see such genuinely intelligent people being confused about something quite basic.

Yes, displacement. Displacement is mass.

As in Archimedes' Principle: Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.

So the gross weight of a vessel will always be the same as the weight of the water that would fill its volume below the waterline.
And water is heavy: 2.8 tonnes per 100 cubic feet.

The bigger you make your hull, the heavier your ship can be.
But the bigger you make your hull the bigger the force that is exerted on it.
Which puts an upper limit to how big a ship made of a certain material can be.

So - how did it sink again?

It didn't.

It got stuck in a shallow, and was abandoned.
Then destroyed by surf and storm.


The only way to make a truly unsinkable ship would be to have a solid hull made of a material lighter then water.

[Мастер]

So the gross weight of a vessel will always be the same as the weight of the water that would fill its volume below the waterline.
And water is heavy: 2.8 tonnes per 100 cubic feet.

That's what I figured. Except I thought it was 1 kg per litre :P

The point of confusion for me is the different ways people have of wording the same thing!

The only way to make a truly unsinkable ship would be to have a solid hull made of a material lighter then water.

Or to make sure your ship never goes in the water. Or at least not deep water :P

Ever see Erik the Viking?

[Halcyon Dayz, FCD]

Ever see Erik the Viking?

To long ago to remember much.

[tubeswell]

So the gross weight of a vessel will always be the same as the weight of the water that would fill its volume below the waterline.
And water is heavy: 2.8 tonnes per 100 cubic feet.

That's what I figured. Except I thought it was 1 kg per litre :P

I think it does at 1AP.

But at 2AP it weighs 2kg and so on

[Мастер]

Ever see Erik the Viking?

To long ago to remember much.

Just thinking of one particular scene.

[spoiler]The vikings are in a ship in the ocean, and it is sinking. Despite some desperate attemtps to prevent this, it keeps going down, down, down, and then all of sudden, stops. The vikings look at each other in confusion, and one of them asks, "Is the ocean deep?"
[/spoiler]

[KLA2]

Thanks, Halcyon Dayz.

I made a "fun post", then drowned in the unforgiving seas of physics.

You get the gold,

Mactep the silver,

Followed by ... the rest.

I get honorable mention for starting a fun discussion. :wink:

[KLA2]

A shipwreck remembered only because of the great Canadian minstrel, Gordon Lightfoot:

http://www.youtube.com/watch?v=hgI8bta- ... re=related

The Edmund Fitzgerald.

[Enzo]

The big ship that sunk,
that I sing about drunk
then I pee in the lake,
Gitcheegoomee.

[Мастер]

The big ship that sunk,
that I sing about drunk
then I pee in the lake,
Gitcheegoomee.

I'm afraid those who don't know the Gordon Lightfoot tune won't appreciate this one :(

[Enzo]

It's a mariner's life
so I cheat on my wife
and inevitably then
bitch, she sue me...

[KLA2]

Does anyone know
Where to Enzo’s mind goes
When his posts they are made in late hours.

This robot suggests
He would greater impress
If he put cheap shots further behind him …

Kidding, Enzo. Good to have you back. :wink:

[Мастер]

This robot suggests
He would greater impress
If he put cheap shots further behind him …

With that I just find
I am of different mind
Enzo should do what he is so good at!

(This is probably how the PMS thread started :P)

[Enzo]

Egads and forsooth
they are based on the truth
so the shots ain't so cheap that I'm takin'

He sings a real croon
and he writes a good tune
and they all leave me stirred but not shaken