Waldemar

Hello, The excellent sources for the rigging of 18th century Spanish ships are certainly: — Juan José Navarro, Álbum del Marqués de la Victoria 1719–1756, Lunwerg Editores, Museo Naval Madrid 1995, ISBN 84-7782-352-9 On-line alternatives: https://catedranaval.files.wordpress.com/2014/09/mdlv.pdf https://armada.defensa.gob.es/museonaval/aplicaciones/coleccion-marques-victoria/# — Isidro Rivera (ed.), Arboladura y jarcia española de la segunda mitad del siglo XVIII. Compendio Compuesto por: Cartilla Marítima, Santiago Zuloaga 1760 & 1766. Tratado instructivo y práctico de maniobras navales, Santiago Zuloaga 1766 & Reeditada 1806. Reglamento de Jarcia, Marqués González de Castejón 1773, Associació d'Amics del Museu Marítim de Barcelona, Barcelona 2010, B-42878-2010 (includes rope dimensions) On-line alternatives: https://bibliotecadigital.rah.es/es/catalogo_imagenes/grupo.do?path=1006025 https://bvpb.mcu.es/es/catalogo_imagenes/grupo.do?path=151659 — Modelos de Arsenal del Museo Naval. Evolucíon de la construccíon naval española, siglos XVII-XVIII, Lunwerg Editores, Barcelona–Madrid 2004, ISBN 84-7782-959-4 — Isidro Rivera, Joseba Burdain, Jesús J. Adán, Teoría y Práctica Ilustrada de la Maniobra Naval Española según el Marqués de la Victoria 1729–1752, Vagara 2021, ISBN 978-84-09-55974-9 (excellent, detailed explanations, both textual and pictorial, yet without dimensions of the rigging components) Promotional pages of the latter item (by the author):

The conclusions expressed in this thread are out of date, the result, as it later turned out, of a misleading bit of material published in the official monographic publication on Mary Rose. The analysis and conclusions representing my current state of knowledge are contained in the thread: Apologies, and thank you, Waldemar Gurgul

As a kind of epilogue to this thread, I am also including here a case from another, rather distant part of Europe, nevertheless thematically and chronologically highly relevant to the issue. In 1570, the Polish ruler Sigismund Augustus, intending to build a royal fleet practically from scratch, instead of turning to Gdańsk/Danzig, which, after all, was at the time one of the largest, if not the largest builder and exporter of ships in Europe, but over which he had almost no political control, asked none other than the Venetian doge to send an expert (granted) who could design and build ships. Most telling, however, is the expressed rationale for this request, clearly stating that Venice was second to none when it came to the ability to build the best ships in the entire known world of the time. Or at least that is what was thought at the time.

I would also like to add, for the sake of greater clarity, that this very issue, in its historical terms and significance, is indeed very closely related precisely to Mary Rose herself, and more specifically to her incomplete, haphazard and simply wrong conceptual interpretation (or rather only a residual attempt at such an interpretation, limited to ‘forceful’ matching of a more or less random arcs to the contours of Mary Rose's frames), published in one of the chapters of Mary Rose's archaeological monograph. Archaeologists themselves, or at least some of them, are nowadays drawing attention to this fatal circumstance, it is just that no one has so far been able to offer a complete yet convincing solution. In addition, this disastrous state of affairs has also been largely contributed to by the failure so far to offer a proper study and publication of Mathew Baker's manuscript, which essentially, as it seems, describes the Venetian methods he learned there. In fact, even the availability of the manuscript itself is so far strictly restricted to only a small circle of interested parties, maybe not without reason. As a result, in today's historiography and consciousness, “classical Venetian methods” are taken for “classical English methods”, and — quite ironically and also misleadingly — the Baker's manuscript itself is even called the Fragments of Ancient English Shipwrightry. I am attaching below a file with published conference materials from 2003, from which one can see just how weak premises today's doctrine on this issue has been based on (apart from the general historical ones, which by the way you cited earlier, the catastrophically wrong conceptual interpretation of the Mary Rose case and a handful of rather naive explanations, or rather speculations, of a conceptual nature). Sadly, this is the result when technical issues are looked at and explained in, shall we say, a predominantly “humanistic” way. In fact, it may be even surprising that nobody has done anything about it so far, at least not in an effective way, but this, I guess, may have been influenced by more than just substantive considerations. Nowacki Horst, Valleriani Matteo - Shipbuilding Practice and Ship Design Methods From the Renaissance to the 18th Century - 2003.pdf

Thank you very much, Trevor. Yes, a whole series of threads in this area have already been created. The majority of the most mature, and also the most closely related to Mary Rose's case, as they concern the Northern European tradition, are on the sister nautical-modelling forum (easy to find, I believe). All in all, it has been quite a long and difficult road allowing for the eventual breaking free of the overly speculative and yet universally uncritically accepted doctrines of today on this issue.

Anticipating the end of this thread, I would once again like to thank all those involved, especially Martes, whose comprehensive assistance and on a variety of detailed issues proved invaluable. Waldemar Gurgul

Later design parallels Ships of similar design concept to Mary Rose 1511, from different periods and different regions of northern Europe, have already been mentioned earlier in this thread. Below are a handful of such quite numerous, specific examples, ready at the same time to be shown graphically. Among the cases studied in detail so far, mention should be made of the design of the French heavy frigate of 1686 by Pierre Chaillé (relevant presentation to be found in another forum), and the design of the French light frigate l'Aurore of 1697 by Philippe Cochois (awaiting a separate detailed presentation). Here a reconstruction of the body plan of the latter frigate superimposed on her original period plan. Among the fundamental features, decisively determining the similarity of the methods employed, attention should be drawn first and foremost to the order in which the contours of the conceptual frames were formed, as well as the specific geometrical procedures used for this purpose. Identical as in the Mary Rose case, the bottom (green) was formed first, followed by the lower breadth sweeps (blue), and only in the last step were the two sets joined by reconciling sweeps (red), tangentially at both ends. Among other things, it is still worth pointing out here not only the very fact of the use of quarter frames, but also the same specificity of their use as in the case of Mary Rose. And the draught of l'Aurore of 1697 in its entirety, including the body plan shown above (French archives): Regarding the fundamental importance, in conceptual terms, of the hull bottom, which is in fact the design basis of ships built in the Northern tradition (in the literal sense, as opposed to the Mediterranean tradition), and the specific use of quarter frames, this is particularly very well illustrated on the surviving design proposals of French capital warships of late 17th century. Below is a drawing of one such design for a first rate ship by Laurent and Étienne Hubacs from 1679 (French archives), and among the not very numerous design elements (but already unambiguous for obtaining the specific form of the hulls), there are in particular the two design elements mentioned earlier (that is, the bottom featuring its curves and both quarter frames). Notable are the much fuller shapes at the midship than those of the Mary Rose (providing in themselves better lateral stability and, of course, carrying capacity), required for a heavily armed vessel. In passing, only one of the two double master frames is drawn on the plan (the aft one is omitted), presumably because of the quasi-identity of this pair. In fact, it can be said that the entire description of the Mary Rose's design concept so far, even including the comments on the specifics of the shapes and the resulting properties of ships, is also relevant to the above examples (which, of course, no longer applies to their proportions, individually selected for the intended, specific application of these vessels). Also, by the way, it is worth appreciating the overall flexibility of the Northern method, allowing a wide range of shapes to be obtained according to needs and requirements, which is probably why, among other things, it has been widely used for such a long period of time. It is possible to point to more similar period sources, written and iconographic, as well as providing more detailed explanations, but I guess everything should have its limits 😊. Nevertheless, leaving aside the almost unexplored archaeological finds from this conceptual angle, it is probably appropriate to point out, perhaps more as a curiosity, yet attractively much closer chronologically to Mary Rose 1511, the case of an intriguing votive model of a galleon, dated to the late 16th and early 17th centuries, now in the collection of the Historical Maritime Museum in Stockholm (Votive ship -Sjöhistoriska museet / DigitaltMuseum). Although an attempt at a conceptual reconstruction of this model has already been made by Peter Kirsch and presented in his excellent publication The Galleon. The Great Ships of the Armada Era, published in 1990, but now, in the light of recent investigations in this area, it may raise objections due to it being essentially based on English shipbuilding manuscripts of the first half of the 17th century, closer to Mediterranean traditions, which in effect generated the trapezoidal hull cross-sections in this reconstruction, characteristic precisely of Mediterranean three-arc master frame designs. However, the cross-sections reconstructed in this way are quite noticeably different from the round cross-sections featured by the original model, as can be judged from the following comparison graphic (as an aside, an identical treatment was attempted in the inevitably unfinished attempt at a conceptual reconstruction of the Mary Rose herself, published in one of the chapters of the ship's monograph). Naturally, it has to be taken into account that the hull of the original model is probably somewhat flattened in the manner typical of votive models; nevertheless, the specificity of the shapes in this model is quite telling and begs for the use of Northern, single-arc master frame design (plus reconciling sweep), precisely as in Mary Rose 1511. Admittedly, on the one hand, such a choice might be made easier by more confidently establishing the provenance of the model itself (essentially unknown) on criteria other than the shape of the hull, yet, conversely, this very feature might help to establish the place of origin and time of its creation. As for the plausibility of the very specificity of the shapes of the Stockholm galleon model itself, at least in the light of the corresponding cross-section shapes of the wreck of the Swedish naval ship Bodekull, in service between 1661 and 1678, it does not raise any reasonable doubts, as can be compared with the sample graphic below. It is worth noting here that Bodekull was built in the period when English design methods were only just beginning to be implemented in Sweden. The 3D scan of the wreck is made available on the Sketchfab website by Swedish Historical Maritime Museum (3D models by SWEDISH NATIONAL MARITIME AND TRANSPORT MUSEUMS (@maritima) - Sketchfab), and more about this wreck and the ship itself may be found in a paper by Niklas Eriksson, A New View of the ‘Edesö Wreck’: identifying the Swedish naval vessel Bodekull, built 1659–1661 and sunk 1678 from written sources, 2018, and attached below. Eriksson Niklas - A New View of the ‘Edesö Wreck’ – identifying the Swedish naval vessel Bodekull, built 1659–1661 and sunk 1678 from written sources - IJNA 2018-47-2.pdf

Thanks a lot, Patrick. That's interesting and new information you provide above regarding the unfinished process of clearing the ship. Also, this is probably a good time to say that your adventures or endeavours, especially those concerning the formation of the hull shapes of your impressive Mary Rose model, which you show in your thread, also influenced the very idea of dealing with this case .

Admittedly, It was still planned to make and present a regular line plan of the underwater part of the hull, possibly for use in model building, for example. Instead, until then, for a demonstration of the final shape of the underwater part of the hull, below are quick renders including waterlines, perhaps best illustrating the nature of the Mary Rose's hull shapes. As a reminder, the waterlines shown here are purely consequential, that is, they took no part in the formation of the shapes (i.e. on the basis of the cross-sections, waterlines and buttocks synchronization, procedure not applicable at the time). These were obtained in their entirety by the found design method shown earlier.

Agreed. Overall, the hull shapes may be considered successful indeed, deserving the term ‘the noblest shippe’ — the lines of the hull seem to be sharp enough for the ship to move and keep to the wind well, yet not excessively, which would only make her prone to the pitching effect and to the rapid hogging as well (incidentally, as could be revealed from the wreck's scan, at the time of her demise, some 1.5–2 feet at the midship). Just that circular hull cross-section with the narrow bottom, and the resulting lateral stability problems...

Thank you, gentlemen, interesting reading. My personal perception is that the very attempts to resolve quite specific technical issues solely on too high, shall we say, general cultural or humanistic level, which may in fact lead to virtually any conclusion, emphatically confirm the necessity of a relevant and routine study of the wrecks (preferably in the context of other artefacts from the period — iconography, written sources), precisely from the conceptual angle, and not primarily from the carpentry angle, to which it has so far usually been confined. Otherwise it will be a kind of chasing one's own tail, which is unlikely to lead to anything authoritative. In fact, it is even worse than that, because a few decades ago such considerations, based mainly on general historical premises and only rather selectively and at the same time overly flexible to sources of a technical nature, led to voluntaristic or even fanciful hypotheses and theories which today do not stand up to confrontation with the results of analyses of a conceptual nature. Nevertheless, now these theories, unfortunately already well established in the popular consciousness, are naturally defended by their authors and proponents, including by attempts to discredit troublesome, later contributions in probably every possible way, and even by attempts at bribery, preferably for the cessation of relevant research in this area altogether (I know what I am writing about ). Let me use an example. It has been hypothesised above that Henry VIII's shipwrights had an incentive to gather ideas widely, due to the ruler's inclinations on the matter. Maybe, but at the same time it is known that shipwrights are probably one of the most conservative professional groups because of the risk of paying too high a price for experiments with unknown consequences. Besides, it is known from sources that they were able indeed to refuse their rulers, such as the above-mentioned refusal to overhaul the Genoese carracks, or the refusal to rearrange the bow of one of the large ships (Great Harry or Mary Rose) to install additional heavy guns there. A rather apt summary of this issue is perhaps Duhamel du Monceau's comment, which makes it clear that the shipwrights stuck rather tightly to one design which they considered good enough, implementing it repeatedly in subsequent builds, and for this very reason encourages them to be more adventurous in their experimentation. With greater effect? Personally, I doubt it, in keeping with the paremia — tempora mutantur, sed homines manent eodem.

Personally, I associate the implementation of the three-arc master frame design in England with Mathew Baker's educational trip to Italy in the early 3rd decade of the 16th century, precisely to learn Venetian ship design techniques. However, your suggestion that Spanish involvement during Queen Mary's reign may have influenced this transformation also seems plausible, given that the Basque whaler San Juan, dating from around 1550, also exhibits just such three-arc master frame configuration. And, after all, the two supposed causes or stimuli need not be at all mutually exclusive, quite the contrary...

To be honest, I am not sure that the widespread dissemination of ideas and methods in this later period does not already make such very late Portuguese examples not very authoritative, however, when one looks, for example, at the designs of the master frame by Portuguese Fernando Oliveira from around 1570–1580, such a view already takes on the characteristics of plausibility. They are round, and have a quite narrow bottom. As do most of the designs for seagoing ships in Livro de Traças de Carpintaria, 1616 by Manoel Fernandes, a Portuguese too, which also demonstrate essentially quite circular sections and narrow bottoms. Below are master frame designs from the manuscript O livro da fábrica das naus by Fernando Oliveira, all sporting a single-arc contour and relatively narrow bottom.

Yeah, as we've discussed before, those round hull cross-sections ‘screamed’ to be corrected as soon as heavy artillery started to be installed on the ships. However, the Mary Rose was not one of them neither. It even occurred to me that until the adoption of the Mediterranean three-arc master frame design, the ships were built as before, i.e. sporting single-arc master frame, and immediately “upgraded” to the new standards and needs by those side “blisters”. Perhaps they simply could not design any differently than before. And this is why there was such widespread and rapid adoption of this Mediterranean specificity in Mathew Baker's time.

I will also take this opportunity to attach the paper by R. C. Anderson dated 1960 and published in The Mariner's Mirror, which indeed cites an extant document of this nature and from this very period. It concerns the ship Mary of the early 16th century. The set of figures is admittedly somewhat different from the list above, and the values given are absolute (as opposed to relative proportions), nevertheless a number of the items recorded relate specifically to hull shapes and not just the size of the ship and its components. Anderson R. C. - The Mary Gonson - Mariner's Mirror 46, 1960-3.pdf

It is quite possible that in this way we are entering the realm of speculation as to events that may have actually taken place, but the idea itself is most pertinent, because this is exactly how things were done, that is, a set of values defining the geometry of a ship was written down numerically, which in effect quite unambiguously recorded the features of a particular design and later made it possible to reproduce it faithfully. Provided, however, that the design paradigms, i.e. the design methods with their specific handling procedures, were identical. This is also a good opportunity to complete such a basic list found at the beginning of the thread (entry #4) and to group together in one place all, hitherto somewhat scattered data of this kind. Slightly reiterating here, assuming that the English shipbuilders followed exactly the same design methods as their French counterparts, and that these were as interpreted above, for a faithful reproduction of the underwater part of the hull they would have needed the following set of data from this alleged agent: Mary Rose (1511) – dimension set General dimensions Breadth outside planking 40 feet Breadth inside planking 39 feet 4 inches Length between posts (at 3rd deck level) 3.5 x breadth outside planking 140 feet Length between rabbets (at 3rd deck level) 3.5 x breadth inside planking 137 feet 8 inches Draught at midship (without keel) 1/10 x length between posts 14 feet Keel assembly & lengthwise division Forward rake 2/13 x length between posts 21 feet 6½ inches (21.54 feet) Radius of the stempost 3/4 x breadth 30 feet Aft rake 1/13 x length between posts 10 feet 9 inches (10.77 feet) Height of sternpost height of 1st deck at midship (10 feet) + height of 2nd deck at midship (7 feet) + height of 3rd deck at midship (8 feet) + rising of 3rd deck aft (6 feet) 31 feet Keel length 10/13 length between posts 107 feet 8 inches (107.69 feet) Placement of double master frame 6/13 of the hull length (fwd) 7/13 of the hull length (aft) Placement of quarter frames 3/13 of the hull length (fwd) 10/13 of the hull length (aft) Risings and narrowings — Line of the floor Deadrise at midship 6 inches Rise forward 6 feet Rise aft (height of tuck) 12 feet Breadth of the bottom at midship 1/4 x hull breadth 10 feet — Line of the breadth Height above waterline at midship 3 feet Rise forward 5 feet Rise aft 7 feet Reduction of the breadth at quarter frames 1/6 (fwd) 1/5 (aft) Transom length 4/9 x breadth ca. 18 feet Quarter frames Radius of sweeps of the bottom 6 feet (fwd) 10 feet (aft) Radius of lower breadth sweeps 12 feet (fwd) 12 feet (aft) Mainmast position 1/2 x length between posts

Thanks a lot, that's one of the very reasons of this presentation . It is also worth remembering that seagoing ships sporting short hulls must have sharp underwater hull lines.

Thanks, yes that is an otherwise pertinent question. Admittedly, there is a corresponding specialised function in CAD software and everything is done in a flash, however, in actual size, or even drawing manually to scale, it is also or can be trivially easy. Please see the diagram below. I have drawn a simple instrument there, for example a wooden or plastic one. Basically it's a flexible strip, and it has two segments. The wide, unbending segment of it is applied to the straight lines of the bottom (or to the straight dashed lines in the diagram if the curves of the bottom are arcs), and the remaining thin and flexible part of it is then bent until it reaches the lower breadth sweep. Ideally, the bending force should be applied roughly at the spot of the expected touch point with the lower breadth sweep. Edit: on this issue see also entry #75. If you still have any issues, please go ahead.

Refinement Already during the work in progress, a 3D scan of the Mary Rose wreck was accessed (many thanks to the Mary Rose Trust, and especially to Alexzandra Hildred), and although just of the ship's interior, with only a residual surfaces of the exterior planking, the scan nevertheless allowed an additional verification to be effected and even some refinement of the results already obtained as well. First of all, the scan itself had to be corrected, which proved to be quite difficult in itself due to the particularly severe and at the same time extremely complicated nature of the distortions of the original (wreckage). Overall, this verification went happily well, except that it sparked an additional local correction of the bow shape, consisting of a slight increase in hull volume at this area. Most importantly, however, the previously found design concept of the ship could have remained unchanged, and even the correction of the bow shape itself could have been done precisely in a way that made use of this previously found design method, specifically by reducing the initial radius of the arc of the bottom in the forward quarter frame from 10 to 6 feet. All the rest of the geometric components followed ‘automatically’ the existing geometric procedures of the design, generating, in effect, a more full bow shape. It could be said here that this is one of the main advantages of this particular approach or way of interpreting finds of this kind. The graphics below show, among other things, pairs of corresponding contours for each station being compared, the outer lines representing reconstructed lines and the inner lines being cross-sections of the interior of the hull (thick yellow lines). The distance between these contours is, of course, due to the thickness of the frame timbers and also, in a rather irregular manner, to the thickness of the ceiling planking, riders, braces and knees. * * * The final (or refined), reconstructed body plan of the Mary Rose 1511 is as follows, and the alterations, compared to the previous variant, affects only the fore part of the hull. All of the earlier explanations on the design concept, or geometric construction, apart from the change in the value of one radius mentioned above, remain valid:

Thank you, Martes, for this information. Somewhat spontaneously — there is a bit of irony in the fact that, for interpreting this particular case, it is the French sources that have proved so pertinent (mentioned above carrack Columbe c. 1500, Fournier's remarks of 1643, the design of l'Aurore 1697 and other French ships of the era, Duhamel du Monceau's treatise of 1752) . It should be noted that these are strictly technical issues. Up to now, as far as I am aware, attempts have been made to create such a conceptual reconstruction of the Mary Rose, however, they were based rather on English shipbuilding textbooks 100 years and more later, which describe issues that were already specific to a period when Mediterranean methods had already been adopted in England for good and developed further. Consequently, these attempts could not and indeed did not produce any meaningful results.

Thanks. I have tried to formulate the explanations as clearly as possible, even avoiding unnecessary additions that only obscure the whole picture. If there is something specific that needs more attention, just please point it out.

In general, I think it can be said that during the actual assembly of the frame structure on the building ways, the procedure was just as you explained. However, there is not at all any contradiction in this with the necessity of some frame pre-designing, because in order to use aligning battens or ribbands at all, first the shape of at least a few frames, erected in the first place even before the ribbands could be fitted, had to be defined. Only then could all the rest of the frames be erected (or even shaped according to these temporary ribbands). Similarly, in cases, when the shape of all the frames is predefined, not merely the conceptual ones, these alignment ribbands are still needed to guide the next, gradually inserted elements into the skeleton structure. Especially since at that early period the frames were not yet a unified whole, but their individual elements (floors, naval timbers, 1st futtock, 2nd futtocks, ..., toptimbers) were not connected to each other at all (so-called ‘floating’ frame components, precisely as in Mary Rose's case). This circumstance, in turn, meant that matching such separate components to the guiding ribbands, even if they had been not overly precisely cut beforehand, was almost always (better or worse) possible. However, the more precisely the whole process was carried out beforehand (i.e. designing, tracing, cutting out timbers), the less work there was with the subsequent dubbing of the resulting hull surface. In this context, it is telling and interesting to note that in Russian shipyards in the 18th century (i.e. at a time when full design on paper was employed), whole teams of carpenters were permanently employed to do nothing but dubbing, although such a peculiar “extravagance” could probably only be possible in state-sponsored ventures. But this is a familiar problem in England itself as well — William Sutherland, in his 1711 work, even strongly advocated a return to simpler design practices, essentially inherited from the Middle Ages, allowing or facilitating greater precision in all preceding stages, precisely to avoid or at least reduce this essentially rather ‘idle’ in the production sense and also economically damaging process of dubbing. To put it yet another way, these first ‘futtocks’, to which guiding ribbands or battens could be later attached, also had to be designed in a meaningful/regular geometrical way, because some random shape of these initial ‘futtocks’ would not have ensured a run of the required shape and at the same time fairness of these guiding ribbands or battens. This is precisely what this reconstruction shows — the design process of these first ‘futtocks’, only here they are called ‘conceptual frames’. Building models using the plank-on bulkhead technique is also a very good analogy. On sloppily designed bulkheads, i.e. sporting rather random shapes, it is virtually impossible to lay the planking in a smooth way. It is also worth adding that the pre-definition of the frames did not necessarily start as late as the implementation of carvel construction. For example, I am now looking at the lines of the so-called Newport ship of the 15th century, sporting clinker planking, and it tentatively looks to have been designed using exactly the same method as was employed for Mary Rose 1511. But indeed here too it is worth doing a proper survey for verification. Yes indeed, it is not a single-arc curve, but in this case it is a curve composed of two arcs of a circle (in the top projection), as is its part for the aft half of the hull. It is interesting, and probably usually surprising to today's readers, that in fact this line did not even have to be drawn beforehand on the longitudinal projections, but its coordinates could immediately be approximated on the body plan in actual size on the mould loft, especially with the help of various geometrical devices of the mezzaluna type. This was possible and at the same time particularly easy for the central segments of this line (indicated in the reconstruction diagrams above), which are already just single arcs of circles, because these central segments, i.e. between quarter frames, are tangent to the longitudinal line parallel to the ship's axis. This is a broader and interesting issue in itself, but I think I have just produced an excessively long elaboration anyway...

Oh, I should also add that the renders in the first post show the reconstructed geometric model in an earlier version, that is, with a slightly larger forward rake than in the later, final version. This of course has to do with the incomplete wreckage (no bow) and having to choose between several possibilities. I could, admittedly, replace these renders or add new ones quite easily, but essentially the intention is that the design method recreated for this case, and presented in such great detail, would enable interested individuals to create a plan or model of this ship themselves.

Thank you Trevor. The shortest answer is that both. But indeed, this is a more interesting issue (at least to me), deserving of a slightly more extensive response. To start, yes indeed it is a kind of reverse engineering, hellishly difficult, time-consuming and fraught with the risk of an easy mistake, especially since in this particular case the input material (a shipwreck), is far from ideal in the sense of its present geometrical regularity of shape, and secondly this exercise had to be based on material already interpreted (indirect illustrations instead of, for example, a 3D scan of the original object), which creates additional complications and risks. The aim is to create a complete, coherent and unambiguous conceptual (geometric) (re)construction, which makes it possible to obtain just such a shape as a whole. For this era, they still have to meet the condition of obtaining immediate ideal shapes, in the sense of their fairness, as in those days design on paper, at least complete design, was not yet practised, which only allows for smoothing treatments already in the design stage (i.e. synchronizing cross-sections, waterlines, buttocks, possibly diagonals). In general, it can be said that the geometric methods applied cannot be completely arbitrary, but must follow firmly from procedures and methods known from written and graphic sources derived from period shipbuilding treatises, manuals, drafts etc. However, this is not a limitation, quite the contrary — familiarity with methods known from these sources makes it easier, if not at all possible, to make such reconstructions successfully. I would also add that I would probably never have obtained (I trust) the correct result in this particular case if it were not for the knowledge and previous experience gained in several dozens of similar projects, and always based on period material (whether plans, wrecks or period models). Ultimately, it turns out that through this graphical method of analysis, it is possible to find out (or prove) things that are absent or too vaguely described in the relevant written works for just a particular region and time. In other words, its results perfectly complement and even correct the current knowledge derived from unfortunately incomplete written sources of the period (and mistakenly or too arbitrarily interpreted today). Perhaps it is a kind of deficiency in my descriptions that there is not a detailed reference to the sources for every detail every time, but such a way would hamper my essential task and, moreover, in the vast majority of cases, I guess it would easily exhaust the readers. In this sense, I do indeed have inclinations to show finished results rather than ways of achieving them. I hope I have formulated all the above and touched the issue in a way that answers your concern or question .

Thank you for your attention so far, Waldemar Gurgul