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Member (Idle past 2915 days) Posts: 158 From: Mesopotamia, Ohio, USA Joined: |
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Author | Topic: About that Boat - Noah's Ark | |||||||||||||||||||||||
Quetzal Member (Idle past 5902 days) Posts: 3228 Joined: |
Deleted by Q due to duplicate post.
[This message has been edited by Quetzal, 08-26-2003]
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Quetzal Member (Idle past 5902 days) Posts: 3228 Joined: |
Hee hee. No lie, amigo. I was on the USS Latrine (err, sorry Racine), a flat bottomed LST that's about as close to a barge as you're likely to get in the Navy. We caught just the teeniest edge of a typhoon in the East China Sea (the Latrine was playing trash hauler taking us from Okinawa to Korea for an exercise). The squids claimed she was taking green water on the bridge sponsons (60 feet above the waterline). I DO know she was taking 23 degree rolls, and digging her prow into the waves at least up over the clamshells. And a fun time was had by all. The world's largest roller coaster is tame - tame, I tell ya - by comparison. More like being inside a cement mixer on "high".
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John Inactive Member |
quote: Not really. Materials, techniques and knowledge change with time. What is possible at one time may not have been possible 3000 years previously.
quote: Yet you made the claim. You back it up. You might notice that forum guidelines require this.
quote: Indeed. A long box would do the same.
quote: Where do you get this stuff?
(In a hogging condition, the deck of the vessel is placed in tension, and the bottom structure in compression.)
Ship Structure Committee: Case Study I: NEW CARISSA It isn't about long term deformation, but about flexing.
quote: So your point is about the distribution of bouyancy? It doesn't make any difference. Riding the waves will make the barge hog. In dead calm waters, a barge will float evenly. A streamlined ship won't. But when traversing wave crests and troughs this becomes irrelevant. A ship the size of the ark will undulate in the waves and crack apart. A barge may in fact be worse, since as the bow dives into the water its inherent bouyancy will drive it back up with greater force that than would the reduced bow of a streamlined ship. Likewise for the stern.
quote: I notice they are all steel, and most are under 400 feet. I thought we were talking about timber? You aren't going to compare steel barges with wood are you?
quote: Sure we do. It was only 5000 years ago. There is a lot of evidence.
quote: Not 5000 years ago, other than that Mesapotamia had a wetter climate. You really, really need to back up this stuff.
quote: There was no "general trend in largeness." It was 5000 years ago, not much has changed. 5000 years is a heartbeat.
quote: The first references I can find to box-girder design refers to construction in the 18oo's. And, in fact, some of the first attempts failed. The engineering experience just wasn't there. So we are to assume that Noah had such knowledge 5000 years previously? It seems to me that if you put hundreds of ten foot diameter beams in a boat 75 feet wide and 45 feet tall, you would have not much room for anything else. Perhaps your design is flawed?
quote: Lets see those designs and calculations.
quote: I don't really care what you said. Why is it that none of the barge specs I have seen match the proportions you propose? Most sit at about 46% height to width. Your propotions are 66%. Were are you getting these numbers anyway? Your ark is smaller than typically proposed. 450' long by 75' wide by 45' tall is more typical.
The dimensions and stability of Noah's ark" quote: If tipped up on its edge, a box is equally likely to fall onto its top as its bottom. Even so, tipping it to 90 degrees would beat everything inside to a pulp. This doesn't help the cause.
quote: What I see is that you are assuming waves, or conditions in general, that won't damage the boat. This is what I suspected, but I wanted you to state so explicitly. The ark's major problem isn't going to be floating at the flood's zenith were you could get long smooth waves-- if such conditions could occur at all in the time-frame. Its problem is going to be takeoff and landing. Water levels aren't going to rise like you are flooding a lock, but will rise more like when a damn breaks. This is the mother of all flash floods. The rising waters will impact the ark with phenomenal force, probably drag it or push it across the landscape and into who know what before the ark starts to float. Once afloat, the waves will be chaotic. The idea that it will ride long waves stem the sterm is silly. It will be twisted and churned by countless smaller waves coming from all directions. Lets not forget that bouyancy is such aerated water is greatly reduced. You've got the same problem when it lands. ------------------
No webpage found at provided URL: www.hells-handmaiden.com [This message has been edited by John, 08-26-2003]
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allenroyboy Inactive Member |
quote: Thats not what I said. According to the Biblical record, God told Noah how to build the Ark. Presumably, God designed it and described to Noah how to build it. On the other hand, Noah may have hired ship designers to design it according to the general description provided by God.
quote: It is your assumption that Noah was a herdsman. There is no such indication in the Bible.
quote: A discussion of the strengh of any ship from any era according to modern knowledge is entirely appropo. But, we cannot assume that they knew what we know. On the other hand we cannot assume that they did NOT know what we know. And if the Ark was designed by God and built by Noah according to a design given him, then the knowledge of shipbuilding in that day may be irrelevent.
quote: 1961, Indian Ocean, aboard the 250' HMS Warrick Castle, on the edge of a typhoon. The ship was smashing through waves as high as the main deck (30-40') with the wavelength about .75 times the length of the ship. Screws were often beating in the air. I was 10, having a great time trying to walk the halls and not smash into the walls and running across stairways as they went flat! Most of the water splashed out of the swiming pool so we couldn't go swiming. Allen
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allenroyboy Inactive Member |
quote:Davis, Andy, 1993, "Understanding the longitudinal deformation of wooden ships: HOG," Wooden Boat, July-August. pp 70-81. In the above mentioned article the author discusses the problem of permanent hogging deformation. Hogging can refer both to the typical flexing that ships encounter and to a permanent deformed condition. AKA "Hogged"
quote:Yes, all large vessels hog and sag in waves, but we are getting away from the point. That point is that a streamlined ship is inherantly weaker for the same size and same construction material than a barge shaped vessel. One example of that is the fact that streamlined ships experience a permanent stillwater hogging that a barge shape does not. quote:Yes, the ark would hog and sag, however, the proper design can keep even a wooden ship from cracking apart. quote:The advantage of a streamlined design over a boxy barge is in moving through the water. The Ark was not designed to move efficiently through the water, but simply to stay afloat. The strength of the barge shape makes up for any differences in stress encounted with waves hitting the vessel. quote:The comparisons I was making was between vessels of the same size and same construction material. However, one can extrapolate from steel designs to wood designs provided you allow for differences in the strength of materials. For instance, the main stressing bearing members on a steel ship about the size of Noah's Ark are the main deck and bottom planking (sic). Typically these are designed at 2 to 2.5 inches thick of steel to withstand the expected stresses of approximatly 9 tsi (tons per square inch) for that crossection area. A wooden ship of the same size would need to have the main stress bearing members (top and bottom) to be about 21 to 25 inches thick. This would spread the stress out over a larger crossection area, reducing the stress to 1 to 1.5 tsi (which is within the compression strength of most hardwoods). quote:This shows up the differences in paradigms between you and I. For me, 5000 years ago was pre-Flood and that all 'ancient' cultures that have been dated earlier than the Global flood some 4000 years ago are dated in error. (yes, I am familiar with all the "evidence" for these 'ancient' cultures, but reject it as interpretation.) Thus, all these "ancient" cultures have no relationship to the pre-flood world. quote:The 'general trend in largeness' that I was talking about is found in the fossil record, which I believe was buried in a global cataclysm and not the result of millions of years based on gradualistic interpretation. (yes, I'm familiar with all the "evidence" for millions of years of evolution, but reject it as interpretation.) quote:As mentioned before, Noah need not have had the experience if he was building according to God's design. The idea that the Ark was a box-girder design is based on the idea that the Ark was a barge built to the ratio of 300x50x30 quote:A vessel of wood with the top deck/roof planking and the bottom planking 21" thick would be able to withstand the typical design stress required for modern steel ship design. quote:I meant to say 300x50x30. This is the size mentioned in cubits. If an 18" cubit is used then you get 450x75x45. If a 21" cubit is used then you get 525x87.5x52.5 quote:The center of mass of a barge that has a draft 1/2 its height will be such that even when tipped abeam up to 90 degress it will be pulled back to the upright position. This assumes that all cargo stays in place (i.e. all animals remain in cages and all food and water remains in their containers). quote:Lets supposed that the major stress bearing members of a barge shaped vessel were the top deck, keel deck and the two sides. For simplicity lets make them all 1 cubit thick constructed of wood. (for simplicity we well ignore transverse members, any other longitudinal members and decks) We will compute this as a box girder supported on two ends. The Moment of Inertia of the crossection for the upper and lower members isI = Ah^2(upper) + Ah^2(lower) + Ak^2(upper) + Ak^2(lower) - (A(upper) - A(lower)) = 21033.34 cubits^4. Where area A=50, h^2=14.5^2, k^2=n^2/12=1^2/12. (k=radius of gyration) The Moment of Inertia for the two sides isI = 2(bh^3/12) = 3658.7 cubits^4 Where b=1, h=28. The total Moment of Inertia is 24692 cu^4 The Section Modulous isSM = I/y = 24692/15 = 1646.13 cu^3 Where y = draft Displacement = W = 15*300*50*D = 225000D lbsWhere D is density of water. Bending Moment = M = WL/8 = 225000D*300/8 = 8437500D cu-lbsWhere L is length of box girder/vessel. Stress = s = M/SM = 8437500D/1646.13 = 5125.7D lbs/cu^2 For a 21" cubit and a water density of 0.03606 lb/cu^3 we can find the stress in psi as5125.7*(0.03606)*21 = 3882 psi This is the stress for a box-girder vessel supported on each end. However, the stress for a vessel supported full length in water is less. The design stress for the cruse ship Savannah (545x78x30 ft) floating in water is 7.67 tsi. However, if the Savanna were to be put in dry dock and supported just on two blocks 545 feet apart, the calculated stress would be about 30 tsi. Thus the design stress is approximatly 1/4 the calculated stress as a beam supported on each end. So if we go back to the calculation above for a wooden vessel the size of the Ark the stress would be 1/4 of 3882 psi which is 970 psi. But what is the crush stress for some hardwoods? White Ash 7410 psiYellow Birch 8170 Sugar Maple 7830 Black Locust 10180 Live Oak 8900 Soft woodsDouglas Fir 6360 psi Western Hemlock 7200 Tamarack 7160 So, the computed design stress of about 970 psi is well within the crush stress of many hard and soft woods. Such a designed vessel is capable of passing the requriments needed for modern ship design.
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crashfrog Member (Idle past 1497 days) Posts: 19762 From: Silver Spring, MD Joined: |
Why doesn't somebody build an ark according to the dimensions of the Bible and see how well she sails? Take a leaf from Thor Heyerdahl's book. Now there's a research program for creationists.
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John Inactive Member |
quote: Tell me about it! But I know why they don't do this. It would afterward be impossible to believe the myth. ------------------
No webpage found at provided URL: www.hells-handmaiden.com
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Brian Member (Idle past 4990 days) Posts: 4659 From: Scotland Joined: |
But I know why they don't do this. It would afterward be impossible to believe the myth. I respectfully disagree. These guys would find some excuse for it not working. We didn't build it exaclty as Noah did because God told Noah how to build it and he didn't tell us. God was watching over the Ark so nothing bad would happen to it. Gopher wood must have been a lot stronger than the wood we used. After all, God told Noah which type of wood to use. You know the sort of excuses I mean, anything to keep the myth alive and keep all those clergymen and creation 'scientists' on the gravy train. Brian
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John Inactive Member |
quote: Why would you concern yourself with a permanent deformation? The boat was allegedly only afloat for a year, tops. This is an irrelevant issue.
quote: No. We are not. You are trying to get away from the point-- the sea-worthiness of the ark.
quote: Yes. I have already granted that a barge is more evenly bouyant than a ship with a clipped bow and stern. What I dispute, is that it makes a difference in storm conditions on the open ocean.
quote: Bloody hell, man! That is what we are talking about. No one today can make it happen. Why do you think a copper age goat herder could manage it? The issue, in fact, is whether ANY design at all would work considering the materials. The Chinese got close, perhaps even managed a larger craft, but we don't know how they did it. The things may well have been braced with iron or steel. The Chinese had had blast furnaces since the 6th century BC-- 2000 years earlier. It doesn't seem an unreasonable thought.
quote: Not entirely. Pointed bows and sterns slice into waves rather than take the full shock of impact. And you've missed the point. I'll repost it.
quote: The point is that the barge designs more evenly distributed bouyancy may cause more stress in rolling waves than would the design of a streamlined ship.
quote: So you say. Do you know how much power is in a 60 foot wave hitting a flat surface head-on?
quote: Then where are the modern 400 foot ocean going barges?
quote: No you can't. The designs of steel and wooden ships are radically different, due to the differing properties of the materials. It is not that simple.
quote: Sorry, but it doesn't take much though to realize that the steel sides of a ship are going to be its lengthwise strength. You seem to applying chord-truss dynamics to something that isn't a chord-truss.
quote: You cannot simply scale up the material. It doesn't work that way. If it did, we could built wooden ships of any size whatever, as long as we used enough wood.
quote: You are forgetting about torsion, shear, elasticity, bending, and various shock loads. Wood is typically high is compression strength, but compression is the least of your problems. Most of the stress will be of one of the other varieties, especially torsion.
quote: Yes, I like evidence. You like myth.
quote: Doesn't matter. Where is the big wood?
quote: Still, were are the big trees? Search the whole fossil record. Where are they?
quote: Invoking magic does not constitute evidence.
quote: BS. A 400 foot long piece of wood 21 inches thick and supported at either end couldn't even support itself. Rolling over storm swells would simulate this condition as well as the reverse-- supported at the center-- over and over.
quote: Cubits... aha.
quote: That is a very big 'if.' What do you think the chances are that everything stays put? After a few rolls, everything will torn loose.
quote: I notice that you again ignore shear, torsion, etc.
quote: Crush stress isn't the problem. Wood is decently strong in compression and tension. Wood is not nearly as strong in shear strength, torsion, and bending strength.
quote: You have forgotten yet another requirement for a ship, modern or not. That requirement is that it be waterproof. The ship will twist and flex as it rides the storm swells. This twisting will cause the timbers to move relative to one another and break whatever water seal it initially had. This was a huge problem in much smaller wooden ships of the 17oo's and 18oo's. ------------------
No webpage found at provided URL: www.hells-handmaiden.com
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John Inactive Member |
I'm sure you are right. The hardcore would have excuses. I do think such a project would be huge blow to the creationist movement, though. And I think they know that.
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No webpage found at provided URL: www.hells-handmaiden.com
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Minnemooseus Member Posts: 3945 From: Duluth, Minnesota, U.S. (West end of Lake Superior) Joined: Member Rating: 10.0 |
I think Noah's Ark is maybe feasible, only if you let God pile on big miracle on top of big miracle. Of course, anything to do with the concept of a "young earth" runs counter to the worldly evidence, and fitting the flood and the major near extinction event into an "old earth" scenario is barely better.
Even if you can accept the mass of miracles, for God to execute a re-creation event in the manner of the "great flood" seem to be far unnecessarily cumbersome at best. One might look upon the "great flood" as some sort of grand metaphor - Call it the "great purge". The ark would be the "mysterious refuge" for the select few who were to survive. Still, no worldly evidence for, and a lot of worldly evidence against. Moose
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Bonobojones Inactive Member |
Having some experience in both vessel design and construction, I've decided to try a little experiment. Using MacNaughton's Scantlings Rules for Wooden vessel construction, I'm gonna calculate the scantlings for a 450' wooden vessel. (There are other scantling rules, but I am familiar with MacNaughton's having worked in that design office for some time.) It'll take me some time as I have to load the calculations into my iMac and figure out the displacement to get the scantlings number. If I can get the time I may even sit down at my table and draft something out to be able to do the proper hydrostatics and stability calculations.
If someone could help me, I need- # of animals/kinds (WTH is a kind anyway?) Amount /weight of food How much time Noah and his sons had for felling/milling the wood and constructing G-D's yacht? My gut feeling is that the Ark is unfeasible. A wooden boat that size, with no way to control it during a tempest that would make the Perfect Storm seem like a summer Sunday sail, would most certainly broach, break apart and be lost with all hands (and paws).
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John Inactive Member |
quote: Yikes! You had to ask, didn't you? The answer? It depends. Two if you follow Genesis 7:9 and 7:15, but sometimes two and sometimes seven if you follow Genesis 7:2-4. What is a kind? A species from which thousands of species can hyper-evolve in the few years following the flood and thus greatly reduce the number of animals on the ark. I have seen figures ranging from 6,000 to 17,000 original kinds. I have yet to see a creationist define 'kind' in a meaningful way.
quote: Depends on the number of kinds. But I have got be eating 1000 to 1500 pounds in a year. An elephant would eat more like 44,000 pounds.
quote: We don't know. Noah is at least 500 when God starts complaining-- Gen. 5:32-- and 600 when the flood starts-- Gen 7:6. The first part of Genesis 6 makes it look like quite a bit happened between Noah's 500th b-day and the command to build the ark, so we should allow probably 50 years max. Oh... and don't forget the really big door in the side-- Genesis 6:16. ------------------
No webpage found at provided URL: www.hells-handmaiden.com
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allenroyboy Inactive Member |
quote:I am really interested in what your results would be. I'm not acquainted with MacNaughton's Scantlings Rules. Are they the rules used for building 19th century sailing vessels? From what I've read one of the major problems with the rules of 19th century ship design was that there was absolutly no knowledge and testing of the strength of materials. Very few, if any, ever measured the stresses that ships encountered. To build a bigger ship one mearly scaled up from emperically based ship designs that had a better success rate than others. What most did not realize is that after a certain point in scaling up, a streeamlined, keel based ship design becomes so weak and flexible that nothing, not even steel bands, can keep it together. All the modern methods of computation and measurement of stress in shipdesign came about with the invention of steel ships, especially during WWII when many of the steel Liberty ships broke apart and sank for no apparent reason. Out of the need to have trustworthy ships for the war effort came modern ship design with special emphasis on strength of materials and stress computations. For these reasons, the design I calculated above is a keeless, box-girder barge design roughly similar to supertankers.
quote:The draft of the Ark is thought to be 15 cubits (i.e. 1/2 the height). With that knowledge you can figure the displacement without need to answer the questions you pose. quote:Experiments with a model in a wave tank (done in the 1980s) show that with a 300x50 length/breadth ratio the vessel automatically turns normal to the waves. But still, no one said that a 110 day ride in the Ark was a walk in the park. [This message has been edited by allenroyboy, 08-29-2003]
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allenroyboy Inactive Member |
quote:Obviously, you know next to nothing about ship design. The one place that experiences the least amount of tension and compression stresses, the one place that experiences the least amount of shear stress is located on the side of a vessel midway between top and bottom and midway between bow and stern. Check it out. Take look a most any modern ship (especially cruise ships) and you will see that they have doors in the sides in the middle of the ship.
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