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Author Topic:   SCIENCE: -- "observational science" vs "historical science" vs ... science.
RAZD
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Posts: 20714
From: the other end of the sidewalk
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Message 518 of 614 (736208)
09-05-2014 8:18 AM
Reply to: Message 517 by Percy
09-05-2014 7:58 AM


Re: Faith responds about "proof" -- evidence shows the earth is old, very very old
Until Faith deals with the observable evidence of old age for the earth, and the consilience of evidence from several different fields, she is living with fantasy.

Age Correlations and An Old Earth, Version 2 No 1

These markers of age are easily observed and easily understood. The evidence shows the earth is old, very very old.

Enjoy.


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RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 556 of 614 (744551)
12-12-2014 8:19 AM
Reply to: Message 553 by kishan
12-12-2014 5:26 AM


tik tik tik
Welcome to the fray kishan,

historical science is came by only observational .

As has been noted all science is observational, the basis of the scientific method starts with observation.

Are you claiming that an hypothesis cannot be formed based on observations? That an hypothesis cannot be formed? That a prediction cannot be tested by further observations?

For instance the finding of Tiktaalik was predicted by observing where there was a gap in our knowledge of the evolution of tetrapods, what kind of environment where the transition from water to land most likely took place, and where on earth the strata was old enough and of the right environment to match. Did finding Tiktaalik validate the hypothesis?

see http://tiktaalik.uchicago.edu/searching4Tik.html

Does this finding show that paleontology is only an observational historical science?

Enjoy

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RAZD
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Posts: 20714
From: the other end of the sidewalk
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Message 562 of 614 (746024)
12-31-2014 10:51 AM
Reply to: Message 561 by Percy
12-31-2014 7:28 AM


workforce?
... but a modern crane made out of wood? Really? I think we should debate how strong that boom could be. Obviously if a wooden boat the size of the ark could exist, so could that boom.

Is that based on historical science or observational science? If we can't do observational science on the past -- including on the way the ark was constructed (which is not in the purported "history" book), then they must be using observational science on past events ...

... the way observational science has been used to study how pyramids were built, how stonehenge was built, etc etc etc ...

And what is the size of the workforce moving all that lumber ... ?

jez askin ...

Edited by RAZD, : ...

Edited by RAZD, : ...


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RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 565 of 614 (746068)
01-01-2015 2:18 PM
Reply to: Message 563 by William Rea
12-31-2014 11:09 AM


thought experiment and turning this into an example of science
... because a wooden structure of that size is not viable on land let alone the sea. ...

Curiously I disagree now, as I have in the past, as a simple thought experiment readily shows that such a bald statement is false:

Take a solid block of wood -- is it "viable" on land? in the sea? The answer would be yes unless you can demonstrate some unknown stress on wood after it reaches a certain size.

Having established that then the question becomes how much you can carve out of that block and remain viable.

So I consider the ark structural integrity as a rather unimpressive argument unless you are going to actually do the engineering and ship design calculations.

However, I would rather use this as an example of the application of scientific methodology to determining if an ark could be built -- ie turn it into a science project that demonstrates to creationists the value of historical sciences as science.

Whatever they do building this full scale model will be based on science, not on history, because the "rule book" only mentions size and type of wood.

Enjoy

Edited by RAZD, : wording


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RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 567 of 614 (746086)
01-02-2015 9:06 AM
Reply to: Message 566 by NoNukes
01-01-2015 9:52 PM


Re: thought experiment and turning this into an example of science
Why would such stresses have to be unknown? Don't we already know about stresses on the beam of ships that increase with the length of the beam? That's certainly the case for the stress applied when waves pass under the keel.

That loading depends on the wavelength. It is worst when the wavelength matches the ship length; the ship undergoes hogging stress when a wave peak is under the middle of the hull and sagging stress when the wave trough is under the middle of the hull. The amount of stress is related to the amplitude of the waves.

A block of wood with the dimensions of the ark

quote:
Genesis 6:15 in the Bible tells us the Ark's dimensions were at least 135 meters long (300 cubits), 22.5 meters wide (50 cubits), and 13.5 meters high (30 cubits). That's 450 feet long, 75 feet wide, and 45 feet high!

http://www.creationtips.com/arksize.html

The moment of Inertia I is bh^3/12 = (50)*(30)^3/12 = 112,500 cubits^4

The distance c to the furthest side from the neutral axis for a rectangular block is h/2 and the section modulus S = I/c = 112,500/(30/2) = 7500 cubits^3.

For loading you can assume a point load for the wave peak locations for simplicity, and a uniform load w on the beam for the weight of the wood, so the maximum bending moment M is wL^2/8 = w(300)^2/8 = 11250(w) (hogged I'll let you do sagged).

Do you know w?

The bending stress σ is M/S = 11250(w)/7500 = 1.5(w). That doesn't strike me as very dangerous.

For the maximum allowable stress σall you need to know the yeild strength y of the material and the factor of safety you want to use.

Do you know y?

Now I bet you can go through all the known wood species and pick y's, and from their densities find w, and that you will have a large factor of safety left over.

The aspect ratio of length to width is 10 and I believe the average tree trunk has that and more. And the wind load on trees is likely considerably larger than this simple bending stress.

Wood is a very strong material when used properly.

And surely we've done enough cantilever problems to be skeptical about a wooden crane?

A simple stayed system would be large enough for this project and would be simple to design, but it isn't really a factor in the strength of the ship, which was the point I was responding to.

Enjoy

Edited by RAZD, : finished


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RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 570 of 614 (746113)
01-02-2015 3:29 PM
Reply to: Message 569 by Percy
01-02-2015 2:51 PM


Re: thought experiment and turning this into an example of science
... . The problem isn't wooden cranes. Of course wooden cranes are real. The problem is that boom (see Message 561: "I think we should debate how strong that boom could be."). It's open structure is a little hard to see without magnification, so here's a magnified image of the boom:

What are the loads?

This is still smaller than sail masts have been, which carried massive loads on clipper-ships, for example.

Dividing the spar into three or four members can make it stiffer if they are periodically connected. This is why modern crane booms and spars are made from smaller section steel than from a single large pole. The same advantage applies to wood structures.

A good straight grain wood can outperform steel for the same weight.

A second year engineering student could design a wooden crane - that is not a problem.

Enjoy


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RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 572 of 614 (746122)
01-02-2015 6:26 PM
Reply to: Message 571 by Percy
01-02-2015 4:53 PM


Re: thought experiment and turning this into an example of science
Here's an image of a crane with a wooden boom, but of solid wood and at an acute angle:

The crane boom is basically a simple loading design, the load is compression with some bending due to the weight of the boom.

A truss design is not only lighter but stiffer because of basic physics ... you can break a design up into discrete areas and the moment of inertia (stiffness) is the sum of area x square of the distance from centroid, so the further from the centroid the area is distributed the stiffer is the boom.

Here's an image of a crane with a wooden boom, but of solid wood and at an acute angle:

The advantage of a single piece boom is simple construction.

The boom sprang from a creationist's imagination and is an impossible fantasy. ...

Or from looking at steel cranes used in construction. It is not an impossible fantasy, just not done because we have steel to use.

Again the issue is the loads lifted --- I do not see any major loads for normal boat construction that could not be met with a relatively simple crane. The construction needs would not be subject to scaling up, but rather to what can be brought to the crane and then distributed on board.

From the picture you have a boom in compression, guy wires above the boom in tension that hold the boom at the desired angle (likely 2 to control sway as well), then you have the hoist line run also above the boom to a pulley at the end then down to a hoist hook.

Clipper ships used their spars to load and unload cargo, including timber from logging.

The feasibility problem to me is more the feeding and care of the animals -- cleaning elephant poop etc -- with the limited crew.

So I would like to see Hammy do a simple scientific experiment: load animals and food and 8 people in his toy ark (once completed) and then close the doors for the length of time the purported ark was afloat (a year plus?) ... they can dump waste into their lake and pump water out of it with wooden/leather pumps (as were used in old wooden ships to pump the bilges).

Enjoy.


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 Message 575 by Percy, posted 01-03-2015 8:25 AM RAZD has replied

  
RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 576 of 614 (746134)
01-03-2015 9:14 AM
Reply to: Message 573 by William Rea
01-03-2015 5:01 AM


Re: thought experiment and turning this into an example of science
Ironically, you have taken a very literal interpretation of my post but, that is my fault

All I am asking is that you substantiate your claim -- something we challenge the creationists to do all the time, usually padded with smug assurance that we can substantiate our side of the debate with science and objective empirical evidence. Here is a chance to show that.

It's your claim to defend.

Tough to find a definitive answer for what wood and in what condition but ...

Especially when the bible says "gopher wood" but nobody seems to know what that is. So you are going to need to review the available types of woods and make some assumptions that need to be justifiable.

... I would suggest that 3.5 MPa and 380 kg/m^3 is not an unreasonable working figure. ...

On what basis? List woods you feel would be representative and why you chose them, with their known properties please.

Then finish the calculations (I shouldn't have to do your work for you ... another comment often made to creationists).

It's your claim to defend.

Assume that given the lifespans of the generations in those times that the wood would be well kept then it should have dried to a good strength.

So what is the assumed duration of construction and what is that based on? What is a reasonable task-force and why?

It's your claim to defend.

Now when it comes to Hammy's claims they also need to be scrutinized with skeptic eyes:

"Yes, we are constructing a full-scale, all-wood ark based on the dimensions provided in the Bible (Genesis 6), using the long cubit, and in accordance with sound established nautical engineering practices of the era. It should become the largest timber-frame structure in the USA."

So I would love to have Hammy tell us what those "nautical engineering practices" were ... the historical evidence would have to come from sources other than the bible, as it is curiously silent on the subject.

Given the association with Egypt though, one could use the historical evidence of Egyptian tomb ships:

http://www.reshafim.org.il/...imelines/topics/navigation.htm

quote:
Little is left of actual boats. Remains of Old Kingdom boats were found at Tarkhan and Abydos, and King Khufu's ship is well known and demonstrates best how ships were built during that period.

The first dynasty boats found at Abydos were about 25 metres long, two to three metres wide and about sixty centimetres deep, seating 30 rowers. They had narrowing sterns and prows and there is evidence that they were painted. They do not seem to have been models but actual boats built of wood too much decayed to analyse, some suspect that it was cedar, others deny this. Thick planks were lashed together by rope fed through mortises. The seams between them were caulked with reeds. The boats did not have any internal framing and were twisted when they were uncovered.


Their construction techniques were rather interesting giving the limited materials they had to work with ...

from link

quote:
Planks with mortises, tenons and V-shaped holes

In modern ship construction a skeleton is built first which is then covered with a skin. During the Old and Middle Kingdoms ships were built from the outside in. This way of doing things was mostly due to a lack of timber suitable for keels, but continued for centuries after they began importing cedar wood from Byblos which was long enough for keels.

Mortises were cut into the planks into which wooden tenons were inserted. The V-shaped holes did not penetrate the outer surface.

Joining

The irregularly shaped planks were butted together in puzzle fashion until the whole skin was constructed. Because of the need to cut mortises the hull was much thicker than it would have been, had it been built around a skeleton.

A special problem facing the shipwrights must have been the bending of such thick planks (5 centimetres or more) into the appropriate shape.

Caulking

For caulking plant matter such as reeds was used, which was covered and held in place by rounded battens, which were held in place by ropes drawn through holes carved into the planks.

These ropes also kept the whole ship together.

Reinforcing the structure

To prevent deformation and collapse of the vessel, ribs and crossbeams were added. Large-sized ships had to be reinforced in the longitudinal direction as well. In the absence of a keel the flat bottom could warp. A thick rope was tied under tension from stern to bow and provided the necessary rigidity. Khufu's solar boat was strengthened by two girders which ran along either side of the deck and were lashed to the crossbeams.

The reconstructed boat of Khufu

Discovered in the 1950's near the Khufu pyramid, the dismantled boat was put back together again. No metal parts were ever used. It consists wholly of wood and is held together by rope. (The rope used in the reassembling the ancient wooden parts is, of course, modern.)


See link for pictures.

So I would challenge Hammy to either use this construction method, with hemp rope or similar, or justify the use of other methodology with other historically documented nautical construction methods of the appropriate time.

Enjoy


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This message is a reply to:
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Replies to this message:
 Message 593 by William Rea, posted 01-04-2015 4:34 AM RAZD has replied

  
RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 583 of 614 (746156)
01-03-2015 1:50 PM
Reply to: Message 575 by Percy
01-03-2015 8:25 AM


Re: thought experiment and turning this into an example of science
It wasn't the possibility of a crane that was raised as an issue, though the one pictured in the AIG drawing is far too modern. ...

But is that what is actually being used on site or just a painting?

... Not one uses a non-solid boom. ...

Curiously I saw several that were made up of trusses, mostly sideways to control sway ...

but also this one:

And notice how the lighting is used on this drawing:

In profile it is about as "flimsy" as the one drawn for the ark ...

... It was that ridiculous boom. Examine the magnified image again:
Besides the sheer flimsiness of it for its length, look at those square trusses. Without triangular units they'll collapse.

Where? The more I look at that picture the more I am unsure of what it represents. Is that really a truss or a single boom with lighting highlights? It looks solid at the base and blurred\confused\pixelated as it gets closer to the tip.

Triangular trusses are only needed to support bending loads. With the boom in compression intermediate bracing between members lessens the unsupported length of each member while increasing the spacing between them increases the radius of gyration for the boom as a whole (see kl/r below)

You're making some pretty strong claims on visibly flimsy evidence, imho.

... Examine the magnified image again: ...

Conversely, let's look at the unmagnified image shown on http://pandasthumb.org/archives/2014/03/noah-travels-th.html (some funny comments):

Note the sunlight to the right and a shadow on the lower end of the boom?

Besides the sheer flimsiness of it for its length, look at those square trusses. Without triangular units they'll collapse

Again flimsiness is a matter of relative loading -- the bigger the load the more stiffness is needed. For posts in compression the factor kl/r is used to determine if the post is more likely to fail in compression or buckling. You can look up how this affects design ... here is one reference

http://user.engineering.uiowa.edu/...II/CompresionDesign.pdf

Run some numbers and see what you get.

It's your claim to defend.

A bigger issue imho could be mobility (is it on wheels and tracks? does the housing spin?) and toppling.

Enjoy.

Edited by RAZD, : gramer


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 Message 584 by Percy, posted 01-03-2015 2:22 PM RAZD has replied

  
RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 586 of 614 (746160)
01-03-2015 3:28 PM
Reply to: Message 584 by Percy
01-03-2015 2:22 PM


Re: thought experiment and turning this into an example of science
... The one on the right is constructed of small beams relative to length connected by innumerable small pieces of wood creating a huge number of joints. ...

You *know* this how? The posts supporting the hull are ~1/2 the length of the boom ...

The boom in the left image is constructed of two massive beams relative to length and with no joints, and it has support both at the top and in the middle. ...

The overall thickness of the one on the left actually looks thinner than the one on the right ... to me. You see the A-frame because it is not in profile like the one on the right ... and you are seeing a diagonal of the boom rather than a side view ...

The purpose of showing the one on the left is that the lighting used to show the "two massive beams" can also be interpreted as them being composed of double booms with a top and a bottom and a gap between them ... just like the ark boom picture can also easily be seen as a "massive beam" with the side lit up by the sun low to the right ... except (of course) where it is in the shade of the hull.

Given the reasonable doubt involved, I would assume a simple A-frame gantry and mast being seen in profile, as there is documentation of that geometry being used in ancient times. The line from the mast to the tip of the boom could be used to raise and lower the boom, while the line just above the boom could be used to raise and lower the load. The more vertical the boom is the less it is likely to be affected by bending due to its own weight (the ONLY side load).

On the other hand, if you insist on interpreting the picture as having top and bottom booms then THIS picture was provided to you as an example of how that could be done:

The cross-bracing between the sides of the A-frame (you can't tell if it is there or not) prevents side buckling and the ends form cross-blocks between the top and bottom ... and this lowers the effective kl/r.

Just because you *think* the beam is too small for the length does not make it so. There are many many many things that "common sense" gets wrong, but on this forum I would hope that claims that something obviously can't work would be supported by actual evidence that it can't work. Wood is naturally stiffer than metal for the same weight.

That means calculations, and that you need to do them to support your claim (and maybe learn something?)

Now as far as I am concerned this particular argument is like pissing into the wind ridiculous as a critique of the possibility of an ark actually being constructed.

What I am concerned with is the intellectual honesty to use empirical evidence and basic (scientific ) knowledge to demonstrate the reality of a claim. Call me a devil's advocate on this issue, but I don't think an argument based on opinion is valid, no matter who makes it.

I'm not saying an ark could have been built this way, I am saying that you haven't demonstrated that it can't.

Enjoy


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RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 589 of 614 (746167)
01-03-2015 5:20 PM
Reply to: Message 588 by Percy
01-03-2015 4:15 PM


Re: thought experiment and turning this into an example of science
As with Ringo, I'm again beginning to wonder if we're talking about different parts of the image. ...

What Ringo and I see as a reasonable assumption is that if you looked down on the crane you would see an A-Frame shape -- this is a very common very old structure used to hoist objects and is still used in construction today because it is simple and effective. This arrangement protects against side sway with a swinging load, while fore and aft sway is countered by the crane being in line ... and whatever keeps it from toppling forward or backward (hence the cables leading to stakes in the ground in the other pictures).

Curiously, I would be way more concerned about toppling than about the boom buckling. Those counterweights can only be so heavy before they cause the unloaded crane as shown to topple backwards, and that then limits the maximum load that can be lifted with the boom extended before it topples forward. Modern crane operators have charts of extension vs load that are safe to use with the legs out. This does not have legs for tipping support (which it would have if they were mimicking a modern crane yes?)

But it is rather silly imho to argue about the reality of the crane until Hammy actually makes one and uses it, don't you think? He will either be using the benefit of some observational science in the design or he will be actually doing some observational science to make it work.

He's already been forced to compromise his design by having concrete stairwells for fire protection ...

... I've circled a section of the boom that contains many of the cross members I've been referring to:
The boom in the image looks like an attempt to mimic in wood the lattice of the boom of a modern crane like this one:

What I see are pixels not cross sticks, and where the cable to hoist the load gets to the same distance from the top (see just inside your circle upper intersection) you see the *same* pixel connections ... are those also sticks? Or is the white strip just a highlight used to show the sun shining on the boom? Is the cable made of short knotted lengths as well?

And why does the bottom of the boom look like a massive solid boom?

But I don't really CARE what you think is the proposed construction, as I've also shown you an alternative A-frame that had top and bottom elements to each side boom to give you the image you want to see. It would look like what you claim from the side but without any cross struts ...

What I CARE about is that you have not done the calculations to actually *SHOW* that your vision of the boom structure would fail.

This kind of lattice made out of wood would crumble into a pile of matchsticks.

Show me: do the calculations, show your assumptions (loads, yield strength, modulus of stiffness, etc etc etc). What do you end up with for the maximum safe lifting load?

What I am concerned with is the intellectual honesty...

Really?

Yes: do the calculations: show me

Enjoy


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RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 594 of 614 (746191)
01-04-2015 11:40 AM
Reply to: Message 590 by Percy
01-03-2015 8:01 PM


booming right along ...
But anyway, let's shift to the higher resolution image I found:

Like the one I found on Panda's thumb ...

I see no A-frame. I see a boom consisting of two parallel and unconnected beams.

Because that's what you want to see, and I previously showed you that their could be two parallel beams on each side of the A-frame with this type of construction:

... from the SIDE ... so you are looking at the EDGE of the plane the A-frame would be in ...

If you assume the cross members are actually just image artifacts that aren't really there, and that the boom is actually an A-frame that isn't in the image, then of course my objections disappear. But you only just now introduced these possibilities, ...

See Message 583 ...

But anyway, let's shift to the higher resolution image I found:

Indeed, and now look at the outer end where the pully is that the lift line runs over and where the line controlling the lift of the boom is attached:

  • why does the gap between the parallel beams continue all the way to the end with no connection at the end?
  • why don't you see the pulley in the gap between the beams?
  • what does the boom lifting line connect to?
  • is the vertical mast made of one thick beam and one very thin beam?

Inquiring minds want to know.

Again, if I were going to criticize this concept I would look at the small base and the heavy cantilevered counterweight at the top -- a very top heavy small stability base concept prone to toppling imho. This looks like something you would see in a fantasy warcraft type video game, by people with no clue to the engineering of a crane, rather than any imitation of a modern crane imho.

... and your questioning of my intellectual honesty is inexplicable and hurtful. I thought we knew each other better than this.

Sorry, but you made a claim that the boom would be too flimsy and would collapse. All I have asked you to do is make the calculations to show this, which you have resisted doing so far. Curiously I am not convinced by opinion, and without the evidence you have made your case -- you have not provided the evidence to support your claim.

Enjoy

Edited by RAZD, : ..

Edited by RAZD, : subt

Edited by RAZD, : finished


we are limited in our ability to understand
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RebelAmerican☆Zen☯Deist
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This message is a reply to:
 Message 590 by Percy, posted 01-03-2015 8:01 PM Percy has replied

Replies to this message:
 Message 596 by Percy, posted 01-05-2015 6:11 AM RAZD has replied

  
RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 595 of 614 (746193)
01-04-2015 12:20 PM
Reply to: Message 593 by William Rea
01-04-2015 4:34 AM


the solid hull -- as a starting point ...
Hey, it's your 'thought experiment' that you decided to take into fantasy and you're busting my balls over your paradigm that I was going along with for the sake of argument? I have nothing else to go on so I assumed that a C18 wood soft enough to work from here...

http://www.roymech.co.uk/..._Tables/Timber/Timber_index.html

...was a starting point considering that we might be talking about a 'solid block' but that it would need to be hewn to make a container in which case we would need to adjust your section moment OR I am happy to assume a stronger D30 material for a viable subframe with a C18 cladding in which case your model becomes inadequate even as a fantasy thought experiment.

My statement may have been 'bald' but, I obviously made the point about your 'literal interpretation' far too subtly so I will be more forthright. It is fine being a philosophical smart ass and saying that you can conceive of a solid block of wood of those dimensions and do a simple calculation in your thought experiment. Great but, being literally a philosophical smart ass back at you, assuming the solid block can be made from numerous trees how does a solid block function as a boat? It floats but it is not a boat as the term is generally understood unless you can convince me otherwise?

You are overthinking the problem. The purpose of the single block was to show that such a structure would not break in waves that matched the length of the ship, even using a simplified calculation that gives higher stress than a ship would actually experience (there would be partial support along its length rather than point supports -- the USCG has a formula for modeling this).

So if we can agree that a solid block would not break up, and that one with just a thin shell would, then all we need to do is find where we cross the line ... but it should be obvious that some intermediate forms would work, so a blanket statement that the ship would break up is unfounded.

The statement was made in the knowledge that it is generally agreed upon that practical wooden boats over 100m are at the threshold. In this particular case of the Ark Encounter 'classic' design, a wooden boat with no means of steerage has no way to protect itself from swells and waves breaking across it. You can argue, if you like, that the flood could have been pond like and so a boat drifting with no visible keel or steerage (exactly as pictured in the Ark Encounter literature) would not need such. Regardless, modern wooden boat manufacture halted for many reasons at around 100m length mark. ...

The critical length for vessel strength is when the wavelength matches the hull length: under that the hull is supported on closer wave crests and has less stress; over that and the surface the vessel is interacting with is more pond like. At around 2 hull lengths the shape in the wave trough gets pretty flat by comparison.

With no steerage the hull will be turned sideways to the waves (because of the way the water moves in a wave) and will then sit in apparent level water. In usual storms this is dangerous because breaking waves can roll the hull. This could be controlled by towing sea anchors or long cables, but I see no reason to assume their existence.

In this particular case of the Ark Encounter 'classic' design, a wooden boat with no means of steerage has no way to protect itself from swells and waves breaking across it. You can argue, if you like, that the flood could have been pond like and so a boat drifting with no visible keel or steerage (exactly as pictured in the Ark Encounter literature) would not need such. ...

What I would argue is that with no land, the "fetch" for the waves is essentially infinite so the wavelengths would be very very large and probably sync with the tidal waves. Do you know what a (tectonic not tide) tidal wave looks like in the open ocean?

The statement was made in the knowledge that it is generally agreed upon that practical wooden boats over 100m are at the threshold. ...
... Regardless, modern wooden boat manufacture halted for many reasons at around 100m length mark. ...

But here we are talking about sailing vessels, yes? Those ships had massive stresses induced by their rigging and wind, which does not apply to the ark, yes?

... Finally, I will accept as evidence that previous attempts and this attempt will require sub-structures on land and/or afloat to make it viable and, it could be argued that modern H&S requirements mean that less risks have to be taken but, that indicates that quantitative risks exist with such a structure. ...

Part of the problem I see is envisioning the ark as a ship, when in fact looking at it as a barge is much closer to the need of the vessel: a big box with lots and lots of compartments for storing all the animals. That means bulkheads, some running full length and some athwartship and some horizontal. An integrated design would be a honeycomb structure that could have a lot of strength, as the longitudinal bulkheads replace the keel (and modern barges are designed this way).

At the same time I will accept that because it has not been made, that does not mean it cannot be made.

and I sometimes wonder what it would be like to have seasick elephants on board ...

Enjoy


we are limited in our ability to understand
by our ability to understand
RebelAmerican☆Zen☯Deist
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This message is a reply to:
 Message 593 by William Rea, posted 01-04-2015 4:34 AM William Rea has taken no action

  
RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 597 of 614 (746273)
01-05-2015 9:16 AM
Reply to: Message 596 by Percy
01-05-2015 6:11 AM


Re: booming right along ...
But I agree now that the cross members are probably image artifacts. The boom still has problems, as you note later, but not the ones I thought it did, so there's not much point in further discussion.

Agreed. I don't think we can figure out what the artist intended that to be.

Enjoy

Edited by RAZD, : finished


we are limited in our ability to understand
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RebelAmerican☆Zen☯Deist
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This message is a reply to:
 Message 596 by Percy, posted 01-05-2015 6:11 AM Percy has seen this message

  
RAZD
Member (Idle past 637 days)
Posts: 20714
From: the other end of the sidewalk
Joined: 03-14-2004


Message 600 of 614 (746293)
01-05-2015 11:24 AM
Reply to: Message 599 by Percy
01-05-2015 11:17 AM


Re: thought experiment and turning this into an example of science
... But I think both you and RAZD would have to concede that the wooden lattice boom I thought was in that image really *is* impossible. Although somehow I don't think you will.

Indeed. I would argue against impossible without demonstration of same. Unlikely I wood agree with.


we are limited in our ability to understand
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RebelAmerican☆Zen☯Deist
... to learn ... to think ... to live ... to laugh ...
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This message is a reply to:
 Message 599 by Percy, posted 01-05-2015 11:17 AM Percy has seen this message

  
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