SCIENCE: -- "observational science" vs "historical science" vs ... science.

The boom sprang from a creationist's imagination and is an impossible fantasy. It couldn't support itself, let alone loads. I guess it seems possible to you, but I can't guess why. If you know of examples why not post a few images? Here's an image of a crane with a wooden boom, but of solid wood and at an acute angle: --Percy

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. The advantage of a single piece boom is simple construction. 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.

Ironically, you have taken a very literal interpretation of my post but, that is my fault Tough to find a definitive answer for what wood and in what condition but, I would suggest that 3.5 MPa and 380 kg/m^3 is not an unreasonable working figure. 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.Quote from Ark Encounter that provoked my wrath..."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."Edited by William Rea, : Went back and looked at Ark Encounter site again.

It is a fantasy I agree. The design is distinctly modern vis-a-vis the enclosing of the mechanism/operator. It is also contradicted by other artists impressions on the AIG/Ark Encounter site including one showing more expedient and contemporary means of moving materials along with a substantial workforce of around 21 people for which there is a whole new apologetic on AIG so, the Hamster is obviously hedging his bets Edited by William Rea, : No reason given.

What about in Greek, Roman or Medieval times? If you check out on-line articles on cranes there are lots of images of drawings of ancient cranes. Not one uses a non-solid boom.You apparently have some expertise in this area, but just as one doesn't require any other training besides living in reality to recognize the problems in Escher drawings, one doesn't need any engineering expertise to tell that a wooden boom like that would have one property overwhelming all others: incredibly weak and rickety. You can't weld wood, and every joint would be a point of extreme weakness. 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. 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.--Percy

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. 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. 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. 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: 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: - -

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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.

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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.

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

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Planks with mortises, tenons and V-shaped holes

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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.

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

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Joining

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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.

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

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Caulking

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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.

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These ropes also kept the whole ship together.

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Reinforcing the structure

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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.

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The reconstructed boat of Khufu

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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.)

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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

It's a non-problem. The crane doesn't have to lift very heavy loads. The pieces of the ark are no bigger than the pieces of the crane.

Such a boom couldn't even support itself. Lifting pieces of the ark, no matter how small, would be out of the question.--Percy

You're taking issue with a drawing. Maybe the drawing has the wood a little too thin but there's nothing wrong with the principle. I've used wooden A-frames much like that myself.

It was a comment made in passing about the silliness of such a crane boom, made to emphasize the absurd nature of the creationist recreation of a mythical event in that drawing. I can't believe anyone thinks that boom could exist in the real world. I didn't say anything about principles. I'm saying that that specific boom in that specific drawing is impossible. Maybe we're looking at different parts of the image - here's the close-up again: There are no A-frames in the boom, so now I think it's possible we're looking at different parts of the image.But the absence of A-frames isn't why the boom is impossible. Wood is just too fragile, especially at all the junctions. Steel hasn't always been available, but such wooden booms seem to be absent from history. Even today there are plenty of places throughout the world where economics would drive people to cheaper materials such as wood, but such booms are absent from the present, too. If it were possible to construct such booms out of wood instead of steel then it would have been done sometime and someplace.But evidence isn't necessary. Just look at that boom. It's self-evidently impossible. I can't believe you and RAZD give it any credence.--Percy

The boom itself would be an A-frame, although it might not be clear in the drawing. That might reflect on the artist's understanding but not on the viability of the idea. The "mast" from which the boom is suspended would also be an A-frame if seen from a different perspective. I'm no engineer but in the drawing the load would be along the length of the boom, in compression. There's little bending stress at all. As I said, I've used 'em.

Great, post an image.AbE: That boom seems as self-evidently impossible as this Dr. Seuss building: --PercyEdited by Percy, : AbE.

But is that what is actually being used on site or just a painting? 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 ... 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. Conversely, let's look at the unmagnified image shown on Noah travels through time, uses crane to build Ark (some funny comments): Note the sunlight to the right and a shadow on the lower end of the boom? 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 referencehttp://user.engineering.uiowa.edu/...II/CompresionDesign.pdfRun 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

Being used on site? I wasn't aware construction had started. As far as I know, it's just a painting or drawing.I've already seen images like those you posted, which is why I suggested you look them up. They don't look at all flimsy. You're the one claiming that the boom of a crane in an artists conception of the construction of Noah's ark doesn't defy reality. All I was saying originally is that not only is the depicted construction of the ark ridiculous, so is the crane depicted helping in the construction. Why that boom looks possible to you, why you even think it bears any resemblance to any of those images you posted, I have no idea. Let's put a couple booms side-by-side: 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 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. The boom on the right would buckle the first time it was hoisted into place. Except that the mast, which I haven't mentioned before, would break first.--Percy

Here's a different image from ArkEncounter.com: This image depicts cranes more consistent with both reality and the period, but...It shows approximately 23 people. How many sons did Noah have?I found a slightly different image of the other drawing at a webpage over at Patheos, here's a magnification of the crane: What looked like a fairly robust mast is now revealed to be half the width with a rope alongside. The boom is now two pieces of long narrow beam with some unknown material filling the space between (the pulley near the top of the boom is obscured by this material). Speculating too much about this drawing doesn't seem worth the time, it's obviously impossible as drawn.--Percy