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Post by amateur on Aug 21, 2016 11:49:27 GMT
Hi Jules,
Athough I agreewith you onthe possibility of distortion, it can noyt explain the difference in the tilt of the nail patterns in the vertuining just above the side-gallieri s. distortion as you show, is a gradual distortion, becoming stronger at the outer sides of the picture. So, it can be that we overestimate the level of tilt (or even see tilt where there is none), but it can not explain why some of the nail-rows show tilt, while others do not. (Or am i missing something?)
Jan
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Post by tromp on Aug 21, 2016 17:11:41 GMT
Jules,
I too am in total agreement with what you say. Indeed you will find distortion in every photograph, but perhaps could you answer amateur's question: Why aren't the Stützen parallel in this Image and instead lean noticably towards the waist?
gratis bilder
Could you also explain why the Stützen are more or less in the same angle as the rearmost mizzenmast shrouds? Check the rigging plan in Winter's book and you'll see that these are far from vertical. Have a look at this Image of the Gent model in which I have highlighted the angle of the Stützen and the gunport sides in the same colours as in the HZ-Image above. You will see that every line is perfectly parallel.
bilder upload
Can you also explain why the Gent-model gunport lids are clearly rhomboidal and those of the HZ-model in the Image abover are perfectly square?
I said above that I fully agree with what you say about photographic distortion. But here is an Image of the HZM which was pieced together from four individual photographs. Clearly the distortion as explained in your post above doesn't apply to this Image - but the Frames are still tilted. Perhaps you could explain why?
kostenlose bilder
Thanks Peter
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Post by jules on Aug 21, 2016 18:27:45 GMT
Goedenavond Jan (Amateur), Thanks for your input. But, I can not answer all the questions all at once. First I have to focus on the main theme, than I can get into the exceptions. Bear with me please. But, since you want me to... What Peter tried to say with his posts was that he saw a gradual tilting of the framing in the Hohenzollern model that was like the tilting we see at Vasa. What I'm trying to make clear in my last post, is that this gradual tilting of the frames can be seen even when the frames are vertical, not tilted, although they may look tilted. I am glad that you can accept this phenomenon. But there are exceptions. There are frames that are tilted. The frames which are attached to the lower transom, the 'hekstutten', roughly have the same angle to the waterline as the sternpost. Since the sternpost has a tilted position, so has the lower transom, and so have the two 'hekstutten'. At the section of the upper hull behind these 'hekstutten', the frames can be placed in a much less rigid fashion, They can be placed more freestyle because these frames only have to fill the space between the 'hekstutten' and the end of the ship. For example, there are no gun ports to take into account anymore in this section of the ship. There is also a triangular section to fill between the 'hekstutten' and the last vertical frame. In this section of the ship, the 'filler stutten' can no longer be placed between the vertical 'oplangen', because the last 'oplangen' were placed against the lower transom. There simply are no oplangen in this section of the ship. So the normal overlap between the oplangen and stutten that was maintained through the rest of the ship, could not be maintained here: no 'oplangen', no overlap, no forced verticality for the 'stutten'. So the whole concept of placing the frame parts against eachother, had to be discarded in the last section of the ship, the part after the lower transom, or, differently said, the part after the 'hekbalk'. The picture below hopefully makes clear what I mean to say. Here it is.
I hope this picture makes clear that the 'hekstut' 'disturbs' the normal pattern. Please also have a look at the Sturckenburgh frame drawing again to see what I mean.
Kind regards,
Jules
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ara
Junior Member
Posts: 69
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Post by ara on Aug 21, 2016 18:48:44 GMT
This is an interesting drawing. Who made this, and from what source? I´d like to know. Thanks. ara
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Post by jules on Aug 21, 2016 19:35:58 GMT
Hi Reinhold (ARA) and Peter (Tromp),
Regarding the 'little nails' picture. I asked if there is evidence for the construction method used for the Hohenzollern model; is it built plank-on-frame, plank-on-bulkhead, or in another modelbuilding method? Rein, I think your answer was to look at the 'little nails' that can be seen on the photographs of the model. Since you can't attach pictures, Peter was so kind to provide us with a picture, and he indicated the 'little nails'. i think I'm missing something here. How does the occurrence of these 'little nails' constitute evidence for a building method? Please help me out here. Again, I'm trying to find out if there are actual frame parts underneath the planking. Only than can we be sure that the positioning of the nails and bolts are dictated by the actual frame positions. Otherwise the model maker was not restricted by frame positions and could place his nails and bolts at any position on the hull: ad libitum. You guys have done so much research on this model. Is there a possibility to answer this question, or will we simply never know? Please check with the other guys on the German forum. And Rein, please join the discussion. I sure would like to know what you think of all the facts presented here. And I sure would like to know how you came to the conclusion that the Gent model does not show tilted frames. Peter, one of your attached pictures in your post of the 14th of August has disappeared, and so has the one from the 16th. Could you please fix that?
Kind regards,
Jules
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ara
Junior Member
Posts: 69
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Post by ara on Aug 21, 2016 20:02:38 GMT
Hi, Jules,
First, I think, Peter had an error here. He saw a certain type of bolts with flat heads, not my "little" nails. Nails´ heads are not that big. If we could detect the presence of such nails, that in my opinion could indicate a more authentic arrangement of the structures behind. i.e. actual frame timbers. Why would one use them in the first place for fixing the wales on a mere model, if that model had a more rough interior structure? But that´s just my opinion. I could be wrong also, and maybe they are not there. It´s a matter of examining the hull closeup photos.
An ad libitum cannot exist concerning the bolts. We have the kattsporen, steunder, sitter, knien all present in the HZM. So that fixes the places of the bolts, at least for these types of timbers. The others ad libitum? I doubt it. Concerning the treenails there is also a regular pattern. Please ask Peter about that. He has recently fixed all treenails on his model. But regularity of pattern is at least an indication of a regular order behind the planks (in my opinion).
About the Gent. Yours and Sturckenburghs baseline is the waterline with the frames perpendicular to it. But the gundecks rise at the ends of the hull. So the ports must became rhomboical at these places, given untilted frametimbers. It´s a matter of effectively using the guns (the port sills). The ports are rhomboical there in the Gent, aren´t they? Maybe you have a photo of the model left, where we can see this Rhombus form more clearly. ara
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Post by Peter Jenssen on Aug 22, 2016 2:06:46 GMT
Hi Peter (Jenssen), First of all I want to thank you for your contributions. You're absolutely right in saying that for Vasa the vertical gunport sills were not formed by the frame sides. At least not in Mrs. Stolts drawing of the framing of a section of the ship. For the rest of the ship, I don't know, but that will no doubt show something similar. (We absolutely need Kroums work to be certain. Maybe Fred can tell us when Kroums work will be available.) What I'm trying to find out is if we can assume that the vertical gunport sills were formed by the frame sides in the 1660s. The date of construction of the Hohenzollern model. If we can assume that the ports were formed by the frames, the ports give us an indication of the direction of the frames: vertical ports show vertical frames, tilted ports show tilted frames. Witsen drawings and the Sturckenburgh drawing show that the gun ports were formed by the frames. What do you think? Kind regards, Jules Hi Jules, First, apologies for the late response. I'ts been a busy week, and from what I see, it has been a busy week for this forum as well. I'm just catching up now. I am not a historian. Rather, I'm an engineer with a history interest. My opinion on this may not carry all that much weight, but here goes; It is difficult to make a categorical assertion without having all information. Something we may have to accept that we will never have. We do not know what was in the model builders or illustrator's mind when they did their work. What is the purpose of the drawing? What is the purpose of the model? How much effort has been put into describing actual practices vs a presentation of an ideal? This may vary between illustrators, and again between model builders. (by the way, I have not found the original of the Sturckenburgh drawing, only a hand drawn copy. It does seem to be a very well made hand drawn copy though. ) I agree. Both Witsen and Sturckenburgh shows the sills and the frames forming the gun ports. To me, the question is, what does that mean for actual practice? We need to place each drawing in context as to what it shows. If an illustrator were to document how ships were built at the Skeppsholmen shipyard at the time the Vasa was built, would it have been a much different drawing? Would they have bothered shoving the notching of the frames to fine tune angles that don't match frames? Would they bother to draw the haphazard way timbers and little filler blocks make up the framing? I suspect they would probably opt for more of a principle-sketch. It does not look to me like Witsen placed to much effort into getting the angles right in his sketches. Frame and gunports tilt in strange impossible directions sometimes. The second half of the 17th century does indeed look to me like the period where things were formalised and engineered in more of a modern fashion. In Swedish shipbuilding practice, the picture has an added complication from the introduction of English style framing at the 1660s. It seems to me problematic to establish how all ships were build at a particular time. (old style, new style, dutch style, english style, which shipyard, which builder, purpose of ship...) I don't know much about standardising practices in 17th century shipyards, but I suspect that there would not be uniform change of building practices such as happens in modern times, when standards change, construction drawings are updated and everyone follows a pretty uniform development progression. When it comes to the models, I don't know how the models were constructed prior to the existance of design drawings. What I mean is, -later model builders had it much easier as modern engineering processes were adopted. If a ship starts as a construction drawing, and then is framed up in an ortogonal space, as per those drawings, then building a true representative model of that ship becomes much easier. Especially for a true hull shape. (The same way tilted frames would be harder to loft from a construction drawing than it would be for vertical frames for a real ship as well. Building methods and design methods have to be coordinated. Production 101 :-) ) -Recap, short answer, Yes, to me they do seem to show gunport framings with sills and frames as defining edges, but I don't know what that means for either real practices or model building practices. Cheers, Peter(J)
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Post by fredhocker on Aug 22, 2016 9:17:06 GMT
Thank you, Peter J! This is part of the point I have been trying to make, that drawings and archaeological remains show two different kinds of things. Drawings for the most part show idealized versions of things, especially if they are illustrating a treatise - "this is how a ship should be built." In pursuit of this, some details may be omitted or simplified in order to make other points more clear, dimensions may not be accurately represented, etc. In this regard, I have no trouble "accepting" what the Sturkenburgh drawing is trying to show. It is a wonderful representation of the fundamental principles of shipbuilding as the artist understood them and an invaluable document in understanding that world. I have no doubt that the principal of using the frames to form the sides of the gunports was an essential concept in this type of shipbuilding, and I have never said otherwise. On the other hand, a number of finer details that one should expect in a complete and realistic image of a ship being framed are not present, in order to make the drawing easier to understand. For example, the forest of staging needed in the framing and planking process is not shown, and the framing is complete without any of the small braces and other timber needed to tie it all together until it is stabilized by the planking. The drawing thus does not depict the reality of shipbuilding, it presents a very useful, but idealized, picture of certain key aspects of the shipbuilding process (once again, as the artist understood them), and we should be grateful that the artist did it this way. Whether the artist knew what he was seeing is a separate discussion, but still relevant for interpreting the image.
Drawings and reality can diverge dramatically. In the 1790s, the US government sent standardized, detailed drawings of the new class of frigates it wished to build to three different shipyards. These were clearly meant to provide the necessary data to build a class of ships that were fundamentally identical, a process that had already been developed successfully in other countries. However, the resulting ships differed in overall length by 3 meters, as each master shipwright interepreted the drawings in his own way and made his own alterations, usually under the guise of "improving" the approved design.
Archaeology, on the other hand, shows what actually happened, the messy reality of shipbuilding, where the available timber did not exactly fit the designer's requirement, or there were changes made during construction, or some shipwrights were better or more careful than others. It is thus harder here to figure out what the intent or underlying concept was, and in this body of evidence, each find is a unique individual, and establishing what was "normal" is difficult without examining a lot of finds. It may have been normal to take care to get the frames aligned with the gunports at Dirk Hendrikszoon's shipyard, but Arendt Huibertszoon next door worried more about other details and if the frames had to be notched a little bit, that was OK. This is where the designer's concept of how the ship should be built meets the real world, and there are unavoidable adjustments. Some of these are too fine or subtle to show up in a conceptual drawing, and others are not relevant. Small adjustments to the gunport sills are such a detail. The Sturkenburgh drawing does not show any significant difference in port size on the upper and lower tier, even though this is a feature that other source material (such as Witsen's certers and archaeology) clearly indicates to be common. Perhaps the ship represented here did not have graduated ports (apparently unusual, but not impossible), or perhaps the artist did not see it as a significant detail. The key information that the drawing provides is that the frames are arranged to allow them to form the sides of the gunports. If small adjustments were needed in the construction process, that is not a big issue. The archaeological evidence shows that sometimes the port side and the frame side did indeed coincide exactly, but sometimes it did not, and fixing it was just one of the many small trimmings needed to finish the ship.
Generally speaking, the wrecks of later ships (of the 18th century), and especially those built in English naval yards, show surprisingly close adherence to the specifications and design criteria, although there are still small variations and deviations. Ships built in merchant yards show more variation, and ships built to a common design in different yards the same. The English navy had demonstrated by the 1670s the ability to build ships to a common design (the dimensional variation of the 30 Ships program vessels was quite small), while one might expect that that United Provinces, with its separate admiralties, allowd more variation. Perhaps we will find out from Kroum's excavation in Tobago, where he is working on a fleet of Dutch vessels sunk in 1677; they could provide useful archaeological evidence that will put the images and contracts we currently work with for Dutch naval building in context.
I cannot pick and choose which type of evidence to use, I have to make sense out of all of it and construct a hypothesis which allows for all of it. Thus there has to be an explanation why drawings conventionally show the port sides corresponding with the frame edges exactly, while actual gunports on real ships sometimes show clear evidence of notching or adjustment. In this case, the leap is not great, it is just one of the many small variations between plan and execution which make up the design and construction process. In this case, it has larger consequences for another argument, which started over whether frames in Dutch ships were parallel or not, then as we dug deeper into the evidence, became a more detailed discussion over whether gunport sides are a useful indicator of frame orientation.
In summary, I would say that I believe that by the second half of the 17th century, it was more common to build large ships with parallel frames in the Netherlands - the written record, the images, and the archaeological finds all agree, more or less, with variations easily explained. I imagine that there were some holdouts who continued to build in a more old-fashioned way (this is how Van Yk characterized the older bottom-based method generally, but the fact that he felt he had to comment suggests that there were still some practitioners), but that they would show up less in the evidence. As Peter J points out, it was not one big assembly line with a universal change order. I also believe that there is sufficient evidence to demonstrate this without having to look at the gunports.
I also agree that by that time, it was increasingly common to make some effort to coordinate the framing and gunport location so that, as much as possible, the frames could serve as the sides of the ports with minimal alteration. The drawing evidence strongly suggests that this was the concept, while the archaeology indicates that it was still necessary sometimes to notch out one or both sides (although less common than in the early 17th century). For this reason, the angle of the ports can be a useful general indicator of framing orientation, but not a completely reliable specific indicator, depending on the period. The evidence, both historical and archaeological, indicates that notching the frames was decreasingly common (or necessary) as shipyards became more adept at building on pre-erected frames in standardized dimensions (as Jules suggests), but was probably not eliminated entirely.
I suspect that 17th-century Dutch shipwrights would laugh at our obsession with such details and tell us we were wasting our time! It is still fun, though.
Fred
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Post by jules on Aug 22, 2016 12:10:44 GMT
Hello Fred,
Thanks for the elaborate sum up. And many thanks for your key sentence: 'In summary, I would say that I believe that by the second half of the 17th century it was more common to build large ships with parallel frames in the Netherlands. The written record, the images, and the archaelogical finds all agree, more or less, with variations easily explained.' And also for the complete paragraph before last, which I won't cite completely: ' .... For this reason, the angle of the ports can be a useful general indicator of framing orientation, but not a completely reliability specific indicator, depending on the period. ...'.
We've come a long way since this discussion ended on the 4th of July, with the general conclusion that all Dutch ships in the 17th century were built with tilted frames.
But, in my view, there is still one issue to be cleared: does the Hohenzollern model show tilted frames? Peter, in his first post, attached a picture of the back of the Hohenzollern model, showing the difference in tilting between the rows of treenails (frames) and the putti on the gallery. The picture with the yellow and blue lines. I'm working on a post that shows that this effect is caused by photographic distortion also. Need some time though.
(By the way, maybe I misread or misunderstood, but I'm not saying that the Sturckenburgh drawing shows pre-erected framing. It may as well show the framing method where the frame parts are not linked together. Sturckenburgh did not show the planking in his drawing to show the framing, but I do not think he is showing a building phase, in my view, he is showing a building concept.)
Kind regards,
Jules
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Post by tromp on Aug 22, 2016 14:54:59 GMT
But, in my view, there is still one issue to be cleared: does the Hohenzollern model show tilted frames? Peter, in his first post, attached a picture of the back of the Hohenzollern model, showing the difference in tilting between the rows of treenails (frames) and the putti on the gallery. The picture with the yellow and blue lines. I'm working on a post that shows that this effect is caused by photographic distortion also. Need some time though.
No need to bother. Just simply answer my questions.
Peter
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Post by jules on Aug 22, 2016 15:14:33 GMT
To gentleman Tromp,
I won't bother you anymore. Bye.
Jules
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Post by tromp on Aug 22, 2016 15:28:54 GMT
There was nothing sarkastic or anything like that in my previous post. It was not meant to be offensive at all. There is no need for any more treaties upon photographic distortion, I am very familiar with the subject. Instead please answer my questions. In future I'll put a Smiley behind every sentence I write! Peter
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Post by amateur on Aug 23, 2016 6:53:08 GMT
A question with respect to that possibility of distortion. We are looking at the close-by pictures, that are merged together to a sideview. There are also some larger distance pictures. When there is distortion, the distortion should be different in these two pictures, as a result of differences in camera sition. If thereis a frame tilt, it should also be visible in the larger distance side-views. Problem is: the sideview in the book is a bit blurry, so I cant discover the nail pattern.... If wedo not see the tilt, we know there is distortion in one, probably both,pictures. In that case, just using thepictures as conclusive proof (no matter what we want to prove) will bedifficult.
Jan
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Post by fredhocker on Aug 23, 2016 9:17:15 GMT
Jules, I did not mean to imply that you were saying that the Sturkenburgh drawing shows pre-erected frames - I understood what you were after there. I was merely elaborating to make the point that it is a technical illustration that shows some aspects of the construction but not all.
As far as interpreting the angles of curved surfaces from photographs, that is notoriously difficult. However, there is software that could allow a rectified three-dimensional record to be created from the photographs, and from this it would be possible to measure details more or less accurately. This might be a more productive route than trying to cross-correlate features visually. We have done this successfuly with old photos from excavations. Much depends on whether the photos of the model were all taken with the same camera, but it may be possible even if more than one camera was used.
Fred
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Post by jules on Aug 23, 2016 13:31:06 GMT
Hi Fred, Thank you very much for the explanation. It would be great to use this reconstruction program on the Hohenzollern photographs. Where and when do we start? Does it involve me flying over to Stockholm, no problem! Any idea if a program like the one you mentioned, is also able to reconstruct a ships hull out of two Van de Velde drawings of the same ship? I've been working on that for a while now, but I don't seem to make any progress anymore. I just can't find the software that is able to do that. If this is it, wow! Thanks for the info! Kind regards, Jules
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