quote:Originally posted by Mespo: So, how do you build a boat to those dimensions when no wooden boat before or since has come close to that size?
I hate to side with the bad guys but it looks like the Chinese were able to build some cargo ships which at least approached the size of the ark. Historical records record a length of over 400 feet, and one bit of reverse engineering suggests over 500.
quote:Originally posted by Mespo: Fascinating John.
Giving the Chinese the benefit of doubt about the size of their ships, their vessels were still controlled craft with standing and running rigging, masts, sails and a RUDDER.
Call me Euro-centric, but I have trouble believing that the Chinese overcame the hogback problem of large wooden ships 400 years before the Europeans NEVER did. I can picture a Chinese junk towing other junks or barges. I can even picture them rafted together. I guess I need more convincing.
Look up Cheng He on Google. The Chinese did manage to built ships that dwarfed European ships.
I followed your Google suggestion and found 4 sites giving the length of the largest Chinese ships as 400, 475, 600 and 444 feet respectively. *sigh*
But I'll concede that they were bigger than European ships.
I don't know how much information you found, but part of the trouble we have in determining exactly how big these ships were, is that shortly after the expiditions began the Chinese government started returning to a xenophobic international policy. Eventually this attitude became so extreme that the construction of ocean-going ships was forbidden and the plans for them destroyed.
quote:The comparison of the Ark to modern (or rather 19th century) wooden ships has problems.
Indeed. We should actually be comparing it to ships built 5000 years ago, but since there aren't any that come even vaguely close in size, what can you do? Comparing the ark to recent wooden vessels is actually giving the tall tale a lot of leeway.
The 19th century didn't contain the largest known wooden ships, by the way. The largest known such ships were built in Ming China in the 14oo's for the explorer Zheng Ho. His flagship was 400 feet long, and some evidence suggests there were larger ships still. No one in the west has been able to duplicate the feet ( hee-hee ).
quote:When it comes to ship design and strength, a boxy barge is the strongest design.
Prove it. I can think of no reason this would the case.
quote:Hogging: Hogging is a problem primarly for streamlined ships -- steel or wood.
This makes no sense. If you support a structure in the center and leave the ends dangling there is going to be stress on the frame, especially when talking about a structure as large as the ark.
quote:Barges ususally do not have that problem.
Perhaps because barges are not typically run in the open ocean under storm conditions worse than we can imagine?
quote:For wood ships the problem is increased when the primary structural members are pieced end to end the length of the ship as the typical 19th century sailing vessel was. The best way to reduce the effect of hogging is for the top and bottom structural members to be full length (from 'bow' to 'stern') of the vessel.
umm... right. The ark was 450 feet or so. The tallest tree now living is 367.5 feet. It is short by nearly a 100 feet, and is in California, not mesopotamia. It is also only 10 feet 4 inches across. With a length to width ratio like that, it would snap like a twig in storm waves. Milling would further reduce the tree and thus weaken it.
Were is the evidence that such lumber even existed for Noah to use?
quote:Draft: It is thought that the draft of the Ark was 15 cubits (1/2 height). With this draft and barge shape the vessel would be very stable.
So you consider rolling round and round like a pencil to be stable? Everything inside would be beaten to a pulp.
quote:The height of the wave in comparison with the height of a wave is only half the story.
quote:The wave that will cause the worst problem is the wave that has the a wavelength the same length as the ship because the ship will experience the worst sagging or hogging. Even large crosswise waves would not be the problem often imagined.
It isn't about long term deformation, but about flexing.
quote:On the other hand, barges have the same boyant support from stem to stern. So, they won't end up hogging.
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:****Again, a simple search on the internet will find that there are several ocean going barges and companies that construct them. Go ask them a few questions.
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:To be sure, no one knows precisly what was the ecology of a preflood world
Sure we do. It was only 5000 years ago. There is a lot of evidence.
quote:There is interesting evidence in the gologic record that many plants and animals were larger than they are now.
Not 5000 years ago, other than that Mesapotamia had a wetter climate. You really, really need to back up this stuff.
quote:While one cannot point to any specific tree fossil being large enough to do the job, the general trend in largeness supports the idea that there could have been trees large enough.
There was no "general trend in largeness." It was 5000 years ago, not much has changed. 5000 years is a heartbeat.
quote:Lets see some facts and figures that would show that a box-girder designed barge shaped vessel constructed of hundreds of such pieces would "snap like a twig."
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:Design calculations that I've done indicate that given the proper crossectional area of stress bearing members, a wooden ship the size of the Ark could handle most stresses it may encounder.
Lets see those designs and calculations.
quote:I just said that the barge design at the ratios of 300x30x45 at that draft would be very stable.
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.
quote:It would right itself, even if tipped to near 90 degress.
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:I figured you were smart enough to see it for yourself.
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.
quote: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"
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:Yes, all large vessels hog and sag in waves, but we are getting away from the point.
No. We are not. You are trying to get away from the point-- the sea-worthiness of the ark.
quote:That point is that a streamlined ship is inherantly weaker for the same size and same construction material than a barge shaped vessel.
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:Yes, the ark would hog and sag, however, the proper design can keep even a wooden ship from cracking apart.
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:The advantage of a streamlined design over a boxy barge is in moving through the water.
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: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.
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:The strength of the barge shape makes up for any differences in stress encounted with waves hitting the vessel.
So you say. Do you know how much power is in a 60 foot wave hitting a flat surface head-on?
quote:The comparisons I was making was between vessels of the same size and same construction material.
Then where are the modern 400 foot ocean going barges?
quote:However, one can extrapolate from steel designs to wood designs provided you allow for differences in the strength of materials.
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: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).
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: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.
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: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).
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:This shows up the differences in paradigms between you and I.
Yes, I like evidence. You like myth.
quote:Thus, all these "ancient" cultures have no relationship to the pre-flood world.
Doesn't matter. Where is the big wood?
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.
Still, were are the big trees? Search the whole fossil record. Where are they?
quote:As mentioned before, Noah need not have had the experience if he was building according to God's design.
Invoking magic does not constitute evidence.
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.
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:I meant to say 300x50x30. This is the size mentioned in cubits.
quote:This assumes that all cargo stays in place (i.e. all animals remain in cages and all food and water remains in their containers).
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:Lets supposed that the major stress bearing members of a barge shaped vessel were the top deck, keel deck and the two sides.
I notice that you again ignore shear, torsion, etc.
quote:But what is the crush stress for some hardwoods?[
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:Such a designed vessel is capable of passing the requriments needed for modern ship design.
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.
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:Amount /weight of food
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:How much time Noah and his sons had for felling/milling the wood and constructing G-D's yacht?
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.
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.
How the hell do you get the draft without knowing how much weight is on the ship? This is inane. Where did you get this figure? It isn't in the Bible. Who made it up for you?
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.
What experiment? Who performed it? Were are the results published? How large were the waves? How was the model constructed? The devil is the details.
quote:Obviously, you know next to nothing about ship design.
Lol... sticks and stones... and lets not forget the amusing irony.
quote: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.
Try to keep your comments relevant. I notice that cruise ships do have small doors in the sides of the hull about midship. It doesn't matter. These are modern STEEL hulls and the doors are tiny. This is not equivalent to cutting a door in a wooden hull. Now consider the size of this door. The bible doesn't say exactly how big it would have been, but we know that some very large animals must have walked through it. Elephants hit about 13 feet, and an elephant would have to crouch to get through a door that size. This is nearly a third of the total height of the boat. Even if you make a much smaller door-- say, 8 feet-- you are cutting a hole that equals approx. one-fifth the boat's height. Show me a wooden boat with such a feature. Equally important, if not more important than the structural consequences, is the water seal around the door. Your placement of the door, coupled with your guess-timate of draft, puts the door partially below the waterline. How do you seal it?
quote:The only reason for mentioning the permanent deformation was to illustrate the fact that streamlined design is inherantly weaker that a boxy barge design.
"Weak" or "strong" design is utterly a matter of conditions. You cannot choose the best design based upon which design performs better in conditions that do not apply.
quote:I believe that a barge shaped (box-girder) design is capable of handling the tension and compression stresses in the top and bottom stress bearing structural members.
Yes, thank you. I know what you believe. Try providing some evidence. Here is a bit of mine.
Engineers have often attempted to analyze the structures of wooden ships as if they were homogeneous box girders. This is a common misapplication of beam theory. Actually, a wooden ship, especially as it ages, more closely resembles a rather weakly bound bundle of reeds. These reeds are free to slide past each other. If traditionally built wooden ships were box girders, then one would expect to see many tensile failures amidships in the upper deck of a severely hogged vessel; however, this is not the case. Failures in longitudinal structure are infrequent and tend to be scattered almost uniformly throughout the vessel. The idea of "strength decks" or "extreme fiber" is largely irrelevant to the meaningful analysis of old wooden ships. Microscopic investigation reveal a generally low level of stress in "hogged" structural members. There often is evidence of plastic behavior, creep, around fastenings. Large overall deflections in the hull can be achieved with a very small amount of creep around the fastenings.
quote:There has probably not been any need or demand for any that size.
So that bit of evidence hits the bottom.
quote:According to the Naval Architect books and articles I've read, the steel sides of any vessel carry very little of the primary tension/compression stresses.
Why do you focus on tension and compression? Those are only two factors. True. The top and bottom will carry a high compression and tension loads. This is not the end of the calculation.
Look. Build yourself a long thin box out of any material you have. Support each end, then remove the sides. The center sags. You can support the middle only, and get the same results. Now put the sides back and remove the top and bottom. Surprise! Not nearly as much sag as when the sides are removed. If you have ever built anything at all, you should know this.
The sides are not going to carry primarily tension and compression. The sides will carry shear and bending, relative to the ship's vertical dimension.
And you are still ignoring torsion.
quote:As long as differences in construction methods are adhered to, it is possible to scale up from steel to wood.
So you DO believe it is possible to build a wooden ship of any size whatever if we just use enough wood?
quote:No, not forgetting, just starting with first things first. The largest forces a ship experiences are the compression and tension stresses in the main deck and bottom planking. Once you design to meet those needs you move on to the lesser stresses. All are important and must be taken into account and designed for. None of the other stresses, including torsion, are of the magnitude, alone or together, of the compression/tension stresses.
This whole paragraph is just crap. From the same site as previously cited.
The bundle of reeds metaphor implies that the ship is comparatively poor at resisting longitudinal loads due to a weakness in shear.
That would be shear, not compression.
quote:Was I really that unclear in my description or are you being intentionally obtuse?
You misunderstand. You don't use as a beam a board that cannot support itself over its own span. Stack a bunch of such boards together in a loose frame-- Noah could not have done better than a loose framework-- and you are not much better.
quote:In my calculations I only dealt with the following stress bearing structural members, the top deck, the bottom (or Keel) planking, and the two side planking.
There aren't four major stress bearing members, there are quite a few individual planks. The difference can be extreme. Take a sheet of plywood, cut a six inch strip and see how mych weight it can carry. Then do the same with 3/4 x 3/4 strips of wood. Stack them to get a six inch by 3/4 beam and put the same weight on the assembly. You'll notice that the strips bend dramatically, though the dimensions are the same. Of course, Noah would have attatched the various strips one to the other, and that helps; but considering Noah's fastening technology, it wouldn't give you the same strength as would a solid sheet-- as you assume in your calculation.
quote:I did not discuss the needed framework of the vessel to held these members in place, because I thought that you would understand that such a framework would be needed and in place.
I assumed such a framework, but no framework will give you as solid a structure as you assume. Each individual member will move relative to every other and be subjected to a reduced version of the stress described.
quote:What I did above was to get a rough estimate.
quote:This is especially a problem for streamlined vessels where the planking is bent and warped to fit the streamline shape.
Oh come on....!!!!! A box won't twist? Please! Your credibility is suffering. A box is just about the worst design for resisting twisting. Of course, we assume that Noah, goat herder and tent dweller that he was, knew all about cross bracing a massive wooden box.
quote:But it is possible to design a barge shape vessel that can keep leaking to a minimum.
So you say, but can produce no examples or even evidence of any kind.
quote:Then too, the ship was likely afloat for only 110 days.
But partially submerged for some time both before it starts to float and after it runs aground, so it would be taking water for longer than was actually afloat.
quote:It proves what I've been trying to say all this time! It shows that you cannot apply modern, typical, homogenous box-girder design to wooden sailing vessel design of at least the 19th century.
Actually, you haven't previously said quite that.
quote:In this design the "reeds" cannot be free to slide past each other.
This may be the largest problem with your box-girder idea. How do you propose that this be done?
I claim some expertise in wood construction because I have been dealing with it every day for the past ten years. My experience tells me that connecting these massive timbers one to the other in such a way that they neither move nor leak is virtually impossible-- and this with modern fasteners. Noah hadn't a chance. Some of the problems:
1) The initial connection. What did Noah have to use as fasteners? Dowels, tenons, copper nails (maybe)-- that is about it. And this to connect timbers more than a foot and half wide. Granted, timber framers can and do this all the time. Timber framers do not have to deal with waves in a stormy sea.
2) As has been pointed out before, your logs will warp, crack and twist as they dry. This action will break many of the joints. If Noah starts with dry wood, then you have the problem of connecting wood that is already twisted-- huge pain, trust me. And, dry wood will re-absorb water once it gets wet. This, also, will be hell on your joints.
quote:Not only do they need to be securely fastened to the frame, but they also need be securely fastened to each other (which was not done in the old ships).
Check your ship building history. The planking on Roman ships was mortised together. The clinker-built design design relied upon the strength of the shell and is found as early as aboput 2500 years ago. The planks were in fact lapped and fastened together. The caravel-built design is the keel and rib design you mean. The caravel was adopted because it allowed for longer ships. Sounds like you want to do both.
quote:Just because ocean going barges are not built as large as the Ark, that does not mean that they could not be built that big.
It does mean that you cannot cite such barges as evidence, as you did.
quote:Just consider supertankers.
Just consider that they are steel.
quote:So as you can see, the computed Shear Stress (Fv) is far below the maxim shear stress parallel to grain of most any wood. Your concerns about shear stress are not very well founded.
What I don't see are estimates of the sheer load on a ship moving through storm swells. I don't see shock loads, which can be orders of magnitude greater than static loads. And I don't see torsion loads which would, at the very least, wreak havoc on your water seals. In other words, there isn't much useful in your figures. No one in there right mind would build a ship based on these considerations and without the one I've mentioned. It seems you are spitting out numbers without much understanding.
quote:This is contrasted with the distance between top and bottom surfaces of box-girder designs where, like in my ark design, the distance between the top and bottom is some 45 feet.
Assuming the structure redistributes the loads properly...
quote:They would be securely fastened at the verticies and the entire substructure would be diaganally cross-braced longitudinally and transversely.
Please don't forget the fastening methods Noah would have had at his disposal. Securely fastening the joints isn't going to be possible without steel plates and bolts-- and lots of them. You MUST take this into consideration. You can't consider these joints as rigid structures. They aren't. A better tack is to consider them hinges. For example, a mortise joint is very strong in one direction, strong in two directions, less strong in another two, and damn sad in the final direction. It is also vulnerable to shear. It is not enough to tell me that "it will be designed so the joints only take load in the stronger direction." You must show me the design. You must tell me how it is to be designed to make best use of the joints.
And try not to forget that we have to get tens of thousands of animals into this rig.
quote:Where are your calculations to back that up.
Don't need 'em. You've ignored far too many factors. It is your design, you do the work.