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Done. It's no small amount of work, but still only a fraction of what you have given me and, indeed, everyone else.
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Samuel 1650 – a Dutch mid-17th century trader
- Thread starter -Waldemar-
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Done. It's no small amount of work, but still only a fraction of what you have given me and, indeed, everyone else.
Hi Waldemar,
Very interesting analysis again. What do you see in rake and curvature in the stem? Is it a plain single radius?
Very interesting analysis again. What do you see in rake and curvature in the stem? Is it a plain single radius?
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Hi Maarten,Taking this opportunity, I will show the entire geometric construction of the stempost-keel-sternpost assembly straight away.
Length between posts: 3.5 x breadth
Length of keel: 3 x breadth
Ratio of sternpost rake to stempost rake: 1:6 (note: stempost rake measured from the point where the rabbet line crosses the upper edge of the keel and enters the stempost)
Height of sternpost: 2 x height of tuck (note: height of tuck at the waterline level)
Height of stempost: height of sternpost + 1 foot
Longitudinal position of master frame: 1/3 of keel length (see diagram for the determination method)
Draught (without keel): ~1/10 x keel length
Note: the radius of the stempost in the diagram relates to the arc of the (upper) rabbet line.
I think that's about all the necessary proportions of the stempost-keel-sternpost assembly.
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Hi Waldemar,
Thx for clarifying. The placement of the master frame you put on 1/3-2/3 of the keel. Is this measured from the provided archeological frames. To my knowledge Witsen and van Yk put the master frame on 1/3-2/3 of the length between stem and stern post?
So slightly more foreward in comparison to English design.
Thx for clarifying. The placement of the master frame you put on 1/3-2/3 of the keel. Is this measured from the provided archeological frames. To my knowledge Witsen and van Yk put the master frame on 1/3-2/3 of the length between stem and stern post?
So slightly more foreward in comparison to English design.
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To be exact, the longitudinal placement of the master frame of the Samuel 1650 is at 3/7 of the waterline length. It just so happens, almost certainly intentionally, that it is also quite precisely at 1/3 of the keel length (measured in the way shown in the above diagram). This is naturally read from the wreck, as in this case it was a matter of examining the find rather than reconstructing it on the basis of rules derived from written sources (and it was possible to do so at the same time). I am quite sure of this reading, and it also agrees more or less with the reading taken by museum staff when measuring the wreck.It seems that there was not some universally applied rule for the placement of the master frame. Even if it was given at 1/3 of some length, this length could mean different things (e.g. overall length, keel length, length of the waterline, horizontal length of the floor or combinations of these). In particular, taking into account the waterline length makes profound sense, as this (at least partly) makes this placement independent of the variously determined rakes and shapes of the two posts (which may have been larger or smaller in specific merchant or warship cases).
You can have a quick look through my threads on Dutch constructions regarding this issue. I also include below the beginning of the section devoted just to the longitudinal location of the master frame from the book De Zeven Provinciën by G. C. Dik. For a more convenient comparison with this text, I'll add that, counting by total hull length, the master frame placement on the Samuel 1650 is 44% (from the front).
Also, there may have been two master frames, obviously in different positions, but to make things even more interesting, the two master frames need not at all have an precisely identical contour. This is a longer explanation, but perhaps I would be able explain it in more detail in the thread on the Hohenzollern model, because there such a description fits better.
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Witsen writes at page 265 of his book:
(265 I 26)'Ships are at their widest at one third of the length measured from the front: it then narrows towards the stern, and thus makes good speed: if one were to place the widest section further forward, the ship would not cut through the water well enough: if one were to place it further aft, the water aft will be over sailed, and steering will become difficult: this is why one third from the front is the right place for the ship to be widest. From observing beams in the water one can deduce that bodies which are thicker forward, make the best speed.'
(71II 31)'The length of the ship is measured across the stems, which is on the outside, while the depth is measured at one third from the front, i.e. on the main frame, where the ship is at its lowest: the width is measured at one third from the bow as well, at the bottom, at the top of the bilge planking and at the ribband set up at the height of maximum breadth, where the main deck is to be.'
Van Yk:
(page 53) 'The length of the ships is taken from the front side of the stem to the aft side of the sternpost, without the addition of beak heads, counters, etc. (...) The width is taken at the outside of the frames where the ship is widest, which is in well built ships at 1/6 of the entire length forward of the middle'.
Dik's mentioning of two main frames originates from Van Yk:
(page 69) 'The two middle frames, which are entirely identical, are placed at about the middle of the ships, and depending of their lenghths 5, 6, 8, 10 of 12 feet apart, called middle frames'.
He explains how the exact location of the forward and aftwards are found:
Aftermost middle frame:
'Add half the rake of the stempost to the total length of the ship and divide the outcome by 2. The number of feet measured from the sternpost show the location of the aft middle frame.'
The forward middle frame:
'Take the length of the keel between the aft frame and the butt of stem and keel and divide it in four. This produces the distance between the two main frames.'
It should be noticed that Van Yk in several places recommends shipbuilding practices that are not common in use, but which are in his eyes improvements of the daily practice. This might give an explanation fort the difference between both his quotes.
By the way: we are talking about differences of probably millimeters here, maybe not even noticeable in a large hull.
An another by the way: the height of the stempost is measured over the outside, that is the highest point of the post. Not the inner side, as you drew here.
(265 I 26)'Ships are at their widest at one third of the length measured from the front: it then narrows towards the stern, and thus makes good speed: if one were to place the widest section further forward, the ship would not cut through the water well enough: if one were to place it further aft, the water aft will be over sailed, and steering will become difficult: this is why one third from the front is the right place for the ship to be widest. From observing beams in the water one can deduce that bodies which are thicker forward, make the best speed.'
(71II 31)'The length of the ship is measured across the stems, which is on the outside, while the depth is measured at one third from the front, i.e. on the main frame, where the ship is at its lowest: the width is measured at one third from the bow as well, at the bottom, at the top of the bilge planking and at the ribband set up at the height of maximum breadth, where the main deck is to be.'
Van Yk:
(page 53) 'The length of the ships is taken from the front side of the stem to the aft side of the sternpost, without the addition of beak heads, counters, etc. (...) The width is taken at the outside of the frames where the ship is widest, which is in well built ships at 1/6 of the entire length forward of the middle'.
Dik's mentioning of two main frames originates from Van Yk:
(page 69) 'The two middle frames, which are entirely identical, are placed at about the middle of the ships, and depending of their lenghths 5, 6, 8, 10 of 12 feet apart, called middle frames'.
He explains how the exact location of the forward and aftwards are found:
Aftermost middle frame:
'Add half the rake of the stempost to the total length of the ship and divide the outcome by 2. The number of feet measured from the sternpost show the location of the aft middle frame.'
The forward middle frame:
'Take the length of the keel between the aft frame and the butt of stem and keel and divide it in four. This produces the distance between the two main frames.'
It should be noticed that Van Yk in several places recommends shipbuilding practices that are not common in use, but which are in his eyes improvements of the daily practice. This might give an explanation fort the difference between both his quotes.
By the way: we are talking about differences of probably millimeters here, maybe not even noticeable in a large hull.
An another by the way: the height of the stempost is measured over the outside, that is the highest point of the post. Not the inner side, as you drew here.
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So how to explain that the hull's length of Samuel 1650 is only 3.5 x breadth and not 4 x breadth?Well, following this line of thought and reading the proportions and rules given by Witsen and van Yk literally every time (by the way, for both of them this tends to be in the form of a simplistic yet specific carpentry convention rather than a strictly design one), the wreck of Samuel 1650 would have to be lengthened by half its breadth. However this is simply not possible, despite best intentions, even if this 'right' 1:4 ratio has been written down by Witsen up to 300 times and by van Yk 500 times. The same applies to dozens of other design aspects in dozens of other known cases.
In carpentry practice, the both master frames may indeed have been carved out identically, even if there were some design differences between their contours (resulting from the lack of proper synchronisation between the lines of the floor and the max. breadth, as can be seen in some of the source plans), because as a rule these differences were rather minor, even – one could probably say – usually within normal manufacturing tolerances.
In conclusion, I will continue sticking to the best of my ability to study this particular wreck, only comparing the results with Witsen's and van Yk's 'standards', and not applying these 'standards' to reality at all costs, contrary to the readings of the real wreck. This is a trap I would not like to fall into. After all, it is difficult to question sources of an archaeological and other nature, even if they are in conflict with some of the Witsen's and van Yk's suggestions.
...!??? ... As in the attached illustration from van Yk, already reproduced earlier in this thread, by the way? I would only add that the height of the outer edge of the stempost is of little design significance (more carpentry and structural), as opposed to the height and in general the whole run of the rabbet line, which is of fundamental design significance.
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How to explain that the measurements of the Samuel do not match the holy rules? Simple: Witsen says that the rules were applied to the judgement of the master. Nobody said here that the rules should be used up to the millimeter. Of course a man of the trade could make his hull wider or narrower and even deeper of shallower (within certain limits, as we saw on Vasa 
), but still the general rule is undeniably 1/4 of the length. It is important to keep that in mind, because the adaptations the shipbuilder applied to his design can reveal clues for the purpose the ship was built for. Nobody said here that the ratio 3.5 - 1 for length and width is impossible. Diversions happened all the time. You only have to read a couple of contracts to see that is how it happened. It is just interesting to know the reason why the shipbuilder diverted from the general rules.
Please carry on presenting the results of your study here. In many aspects your method is a revelation. But allow us to note what is known to us. It might help to bring two possible explanations together.
As to the rule about measuring from the top of the stempost and not from the inside: it is not even a rule, it's simple practice. Just imagine how to stretch a line from bow to stern. Does it not seem logical to you that the line is drawn over the top of the post?
The fact that Van Yk shows a method how to design a stem has nothing to do with indicating the length of a ship. Apples and pears.
), but still the general rule is undeniably 1/4 of the length. It is important to keep that in mind, because the adaptations the shipbuilder applied to his design can reveal clues for the purpose the ship was built for. Nobody said here that the ratio 3.5 - 1 for length and width is impossible. Diversions happened all the time. You only have to read a couple of contracts to see that is how it happened. It is just interesting to know the reason why the shipbuilder diverted from the general rules.Please carry on presenting the results of your study here. In many aspects your method is a revelation. But allow us to note what is known to us. It might help to bring two possible explanations together.
As to the rule about measuring from the top of the stempost and not from the inside: it is not even a rule, it's simple practice. Just imagine how to stretch a line from bow to stern. Does it not seem logical to you that the line is drawn over the top of the post?
The fact that Van Yk shows a method how to design a stem has nothing to do with indicating the length of a ship. Apples and pears.
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Oh, it was a rhetorical question, and you wrote in response essentially what I wrote earlier, only in different words. Nevertheless, thank you on behalf of other readers.As for the dimensioning of the stempost, if you'll allow me, I'll try to stick consistently to the design convention, as opposed to the carpentry convention. After all, we don't want to mix apples with pears, height with length, etc., do we? By analogy, I didn't even suspect that, for example, the usual way of attaching shrouds to the mast might be illogical.
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Now, the Holy Grail and the very essence of the quest in reverse engineering of old ship designs – the line of the floor and the line of the greatest breadth. Without the reconstruction of these lines, all that remains is a game of, shall we say, empirical nature, by forming shapes by eye, which, incidentally, may even at times produce quite decent results and, for example, an attractive model or painting, but will not, after all, answer the question of how ships were designed at the time.According to the archaeological record, the following relationships and design sequence of Samuel 1650 have been found or guessed, accurately or at least with a high degree of approximation:
– the waterline level was set at eight feet, corresponding to the height of tuck (or vice versa),
– the length of the waterline (not including the posts) has been divided into seven parts (with a subdivision of 14),
– at the stern, the line of the floor aft terminates at the height of tuck and, at the fore, one foot below the design waterline level; at the master frame deadrise has been fixed at three inches,
– the height of the greatest breadth at the master frame is 1/10 of the total length of the hull (i.e. between posts), about one foot above the design waterline,
– the wales are perfectly parallel to the line of greatest breadth (scheerstrook, scheergang).
So much for the essentials of this rather simple design (in conceptual terms).
However, it should also be added that to form the shapes of the main design lines, logarithmic curves were extensively used. These are perhaps the easiest to use in practice, especially as they are ideally suited to achieving the contours of the frames straight away on the mould loft with a trivial simplicity, and without any real need to make any scale drawings on paper in advance.
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Cross-sectionsThe available archaeological documentation, or perhaps more so the rather not inconsiderable degree of the wreck distortion, does not allow a definitive choice between variable and fixed radius of the futtock sweeps in this particular case, especially as the actual differences in their resulting geometry are almost dimensionally negligible, and even for the frames at the extremities of the hull. In this state of affairs, I finally decided on a fixed radius for the futtock sweeps along the entire length of the hull (specifically – equal to the whole breadth of the hull, i.e 26 feet), in accordance with the golden rule of „beautiful simplicity”.
All the other components of the underwater part of the frames contours retain the same parameters as stated earlier in this thread, except that the width of the „flat” could have been reduced from 3/4 to 2/3 of the hull breadth. Either way, the resulting differences in the contours of the frames are so small as to be almost cosmetic in nature.
It can also be added that the „flat” for all frames is a straight line, except for the last two frames it is in the form of an circular arc.
In principle, this stage finalizes the interpretative part of the preserved archaeological material (in conceptual terms), and further possible activities will already be of a rather reconstructive nature of lower importance.
Congratulations are not necessary, because nothing else will satisfy me anyway, except the Nobel Prize
. After all, I am solving problems that generations of researchers, historians and archaeologists could not cope with, including those who grant themselves the exclusive right to understand and interpret the wrecks properly, on the grounds that only they, unlike all the rest, personally touched the artefacts. Quite funny.Well, while it is perhaps not over yet, nevertheless even now many thanks for your attention and participation, especially to Ab and Maarten.
Waldemar Gurgul
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Ab, do we continue with our 'intellectual ferment', now concerning the general reconstruction of the upperworks? Personally, I see another deck about five feet or so above the main deck and an open bow (i.e. featuring beakhead bulhead and the 'wings', so characteristic for this configuration and period. And do you have any suggestions?.
A tempting idea Waldemar. Of course with a big risk of making a nonsensical end product. You might have seen clues for the upper works that I have not, but please do what you like. I will follow and participate with whatever rules I gathered from my sources.
Take a walk on the wild side.
Take a walk on the wild side.
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A very good, well-aimed question.
In the English context we would call them "hollowing curves", "hollow sweeps", "bottom sweeps" or similar.
The last frame on my body plan diagram is actually unnecessary in a conceptual sense, but in practice I had to draw it in addition to the other frames in order to correctly create the hull surface in CAD software, which is not as clever as a hull plank being bent in a natural way and sometimes the computer software requires a bit of prompting of this kind. On the part of an operator, it requires a certain amount of flair and sometimes a few attempts.
In this particular case, the perfect arc turned out to be the arc tangent to the deadrise line, starting from the width of the 'flat' , or in other words, going from the intersection of the two green lines. Alternatively, when shaping the hull surface in CAD, it is possible to use a kind of auxiliary diagonals which also do a good job, effectively replacing this supernumerary frame, but in no way can these "diagonals" modify the shape of the leading frames (i.e. the "conceptual" ones), but can only help to shape the hull surface between these leading frames.
Now for the more important part:
In general, the selection of the 'hollowing sweep' radius for the frames at either end of the hull (meaning already the 'conceptual' ones) must have been somewhat arbitrary, depending on the designer's preference and the specifics of the ship. In this particular case, for the Samuel 1650, I read this radius from the wreck record as twice the hull breadth (i.e. 2 x 26 = 52 feet).
There are more examples of this way of determining the radii of the 'hollowing sweeps', but I will now show only one design – for the ships Prins Carl & Prins Wilhelm 1696. Note in the (still working) diagram below that the radii of the 'hollowing sweeps' are (sub)multiples of the hull breadth, both for the aft frames and the bow leading frames. The original plan was not drawn very accurately and the sweep values are actually taken from the detailed dimensional specifications for these ships, in the form of precise numerical data for each leading frame and for each geometric element individually of these frames.
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Oh, I would have forgotten. Once you've drawn the bilge sweeps and the hollowing sweep/line, you connect them with a reconciling sweep, tangentially on both sides..
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Less harmonious surface..
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What can I say...? This is probably one of the main reasons why we have experienced such stagnation in this field for several decades. Researchers from individual countries have focused almost exclusively on their national sources without noticing the wild ones, because coming from outside. However, the lack of a broader view simply makes it more difficult to understand even their own national traditions, something that has particularly surfaced in such an embarrassing way in the case of the 'Ancient English Shipwrightry' of the early modern period.
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