Waldemar

Eventually, out of curiosity, I had a look at the archaeological report myself. It turns out, quite logically, that the ordinary planking boards were of pine, while those of structural importance, where the individual timbers overlap (i.e. floor, bilge, futtock timbers) were of the more robust oak. The latter were also thicker than regular planking, in effect making them a sort of underwater wales. The report also points out that the use of coniferous wood in the Mediterranean for the planking of ship hulls was quite standard practice at the time.

Is there any regularity of application in this mix of two wood species or does it look more random? What is in the report about this? Because if it's a bit of a haphazard-looking mix, then repairs, necessarily done quite routinely and arguably at varying levels of cost and resulting quality, can probably also be added to these possibilities.

It depends on where the pine (coniferous wood) is used. If for the lower parts of the hull planking, then yes, it could have been a cheat. However, if for the upper parts of the hull (especially the planking of the upper decks, even the planking of the upper sides, or for the inner bulkheads, regardless of their location), then it is already a most correct and desirable practice, advised and described in the ship's handbooks of the period. It is particularly about the difference in weight of oak (or other heavy woods) from coniferous species. As a curiosity — at that time or so, in the north of the continent, there were in fact quite a few ships built entirely of coniferous wood. They were called fyrblasses (in Germanic languages fyr or similar, meaning precisely pine wood).

Correct — Veltman, not Veltmand. The alleged letter ‘d’ is just a fragment of a leaf. But it's best to see it for yourself. link: | Nationaal Archief ... and in its entirety:

To be honest, I hadn't really paid attention to this very detail. Congratulations on your perceptiveness! The designs of this Jan Veltmand are very recognisable from others, and cover a whole range of different vessels. Yet, his full name is found on only one of his draughts. And here, his initials, nice...

Voilà! The lines of your yacht are ready. Since you will be processing it further in the 3D program, I will not be doing 2D drawings as I did previously. Instead, I will send it to you right away via PM in OBJ format. just as you see it below, only without all those design lines which you don't need, just the surfaces themselves.

Almost finished...

Without going into considerations of an academic nature, I will only say that the design of the yacht under consideration is quite detailed for its era and certainly made it possible to build a vessel. For comparison, let me remind of a design from about the same period, according to which a whole series of three whaling ships were successfully built. Please note how ‘poor’ in detail this design is in its graphic form: And yet another design from a couple of decades earlier. Here, not even contours of the bends are defined, and yet this very design was again a base for successful building a whole series of ships: To make a long story short, the content of the book you mention focuses on the „modern” design methods, adopted in the Netherlands by some designers around the second quarter of the 18th century, which in essence are methods adapted from the so-called French methods, in the meaning of using numerous diagonals that were harmoniously divided geometrically or mathematically to obtain the contours of the frames, independently of the traditional design lines such as the line of the floor used up to then. This is already a completely different era in terms of naval architecture compared to the design techniques native to the 17th century and earlier. More on this fully diagonal methods, please see, for example, the excellent works of Jean Boudriot on the subject.

I am always assertive or honest. Unless the demands of courtesy and politeness sometimes get in the way 🙂. I keep hoping that someone will eventually start applying these presented design methods themselves. That is at least the general intention. But in this particular case of this yacht I was going to do it anyway, so I don't see it as a problem to take the extra time to do some additional drafting of simple 2D plans, as I have already done for Samuel 1650 at Don's request. Does this convention suit you more or less? Further on, you will already be on your own.

There is probably no need to guess. There are at least a dozen plans in the archives created obviously by one hand and this very plan is in that group. One of these plans is signed by its designer, a certain Jan Veltmand, and another plan, of a hooker, shows even the name of the ship – ‘Catharina Maria’. It would be enough to check this information to get more exact dating. I personally rely provisionally on the archivists' dating, which seems to me quite acceptable, given the specifics of these designs. Besides, they are kept together with other plans, with dates on them, for example 1728 and 1733. I wonder how one can be sure that they were not used to built actual vessels? In any case, these plans must have been drawn somehow, after all, and all indications are that they are not random scribbles. Here, too, there is no need to guess. I am familiar with the contents of this publication, which is why, among other things, I wrote that the method identified from this plan is so far unknown. Incidentally, other Dutch design methods from the first decades of the 18th century and earlier are also not described in this book. There are at most comments on the plans reproduced there from that very earlier period, of the kind that it is not known how they were designed. By the way, in this group of a dozen drawings by Jan Veltmand there is a plan with a rather similar general layout, that is, with a central cabin and a deep cockpit, itself before a very small cabin aft (National Archief NL-HaNA_4.MST_470) :

Hi, thanks, but it should actually read ‘Jan points in his post #11’ 🙂. Quoting and reproduction for non-commercial purposes is not prohibited, at least according to the law to which I am subject, so below is a copy of that plan whose existence you have reminded us of. Indeed, it's a great example, and even for several reasons, thanks. Meanwhile, I took an even closer look at the design concept of the yacht we are talking about. This method, already using design diagonals to produce variable radii, is simply brilliant in its simplicity and ingenuity at the same time. I think I'll make a separate thread describing this as yet unknown method, discovered thanks to this plan. For now, below, I am posting the almost finished body plan of this yacht. You can see quite well all the drawing inaccuracies committed in the original drawing, but it should be noted right away that more precision was not necessary to draw such a preparatory sketch, as precise tracing was only required on the mould loft. This is also another very good opportunity to show the potential of reverse engineering that takes into account old design methods. Not only does this approach not introduce new distortions when smoothing out hull shapes, but it also further corrects the designers' frequent drawing inaccuracies and later distortions of the original drawings.

There is quite a significant difference in the shaping of the hollowing/bottom curves in Steel's and Stalkartt's work. While the former uses a very traditional way, going at least back to the antiquity, by using a properly curved and scaled wooden template (related to non-graphical methods, i.e. without paper plans), the latter has a different way: simple straight lines for the central part of the hull, much more convenient to draw on paper plans, and the bends/frames at the extremities of the hull are even shaped in their entirety on the basis of previously drawn waterlines (such approach is strictly related to newer, graphical methods of designing). But it is already your job to recognise such specificities in the drawing you are examining 🙂.

Yes, on the one hand this is true. And there are many more such arbitrarily chosen design components in Stalkartt's description. And not without reason, as he describes things in a most valuable, universal way, that is, he lists all these design components, explains what they serve and how they are applied and in what order. Precisely consciously in the most universal way possible, independent of the specific parameters used by individual designers and for various types of boats. Today, without this background knowledge, it is not at all easy to reproduce the design process even with the original plans. It is therefore usual to redraw the lines from the extant plans and then smooth them out by various means. This present-day alternative method is also good for specific goals, but has its own peculiarities and limitations. Yes, plate I and pages 1–28 on whole-moulding.

Right, definitely 40 feet. Confirmed by direct application of the drawn linear scale. I also looked at the method of forming the hull shapes. In its essence, it is not overly complicated, but recreating the main design lines, which have been scrupulously erased from the finished draught, would already be an undertaking for at least a couple of days. This could be quite an interesting reverse-engineering project in itself, as I have not yet investigated such a variant of Dutch-style design. These old methods, correctly applied, actually guarantee perfectly faired shapes.

Oh my...! I feel a little guilty now, because it's like you're starting to follow my footsteps into the abyss of madness 🙂. Or, into a hitherto hardly explored space. I didn't expect you to approach it in such a meticulous way... Anyway, one can see a lot of regularities on your numerical chart, which clearly suggest that the designer used the same procedure and set of proportions in most of the cases you measured. This kind of juxtaposition can help you to reveal the design logic of this particular boat, if that is your wish and intention. However, as you are already aware, such a method and sequence of ships' boats design is described in both of Steel's works (The Elements and Practice of Naval Architecture 1805 and The Shipwright's Vade-Mecum 1805), but probably best and most comprehensively in Naval Architecture 1787 by Marmaduke Stalkartt. More and more publications are being made publicly available by archives and libraries these days, but if you can't find the latter work but still want to consult it, I'll do the scans for you. Just please check availability on the internet resources first, as it is quite a lot of scanning (a whole 28 pages of textual description plus a very large drawing sheet, which I would have to scan six or eight times and then stitch together). Please let me know.

Well, yes and no. On the side view, the contours of the front cabin are indeed not drawn, nevertheless, on the other hand, there are two beams on the top view which would correspond very neatly to both bulkheads of this very cabin. Coincidentally, they also limit in a very convenient way the length of this special doble plank for fixing the leeboard axle. Please note also the lack of continuation of the plank seams on the top projection, which may be intentional. Please do not take my diagram in too literal a manner. It is simply a quick sketch not quite to scale, the intention of which was to show the essence of the configuration, not the exact dimensions. And indeed, this is particularly true of the floor height as well as the height of the roof of the front cabin, which would both obviously need to be corrected or optimised at a later stage. But since you are dismissing this particular concept sporting a deep cockpit, incidentally quite attractive or convincing, it would already be a rather unnecessary exercise anyway...

Ordinary deck planks are indeed not structural elements, like the planks of the side, but the waterway, i.e. the outermost, hefty deck plank at the very side of the ship already is. And on this plan, the plank to which the leeboard axle is attached is even twice as wide as the others, one can assume not without reason. As well as robustness, it is equally about the simplicity of the solution, durability, ease of implementation and eventual repairs etc. One thing can be sacrificed for another.

@Robska From an engineering point of view, fixing the leeboard as on this plan, i.e. to the deck, is preferable (more robust) to fixing only to the side of the ship.

Such a configuration as below? Yes, this is a very convincing arrangement.

As a result, you would get a more or less similar deck configuration:

Of the two, however, I like the leeboard mount variant better. Yes, if it were a scupper, it would set the level of the deck. However, this iron pin may be attached directly to the deck; in the close-up you can see three dots presumably marking the heads of the attaching nails.

Here, please, are some examples with similar attempts. They relate to different periods, places and design methods. I have deliberately cited such a broad spectrum here to show the variety of solutions used by designers of the time. Within a narrower range, for example in terms of time or relating to the same design method, one can find regularities, but today, in practice, one still has to check the various possible variants each time when analysing such plans. In general, when looking for such proportions, start with the smallest integers that divide the reference length. Increase these numbers until you get an adequate correspondence with the plan under examination. Usually the result is below 10, but in one of the examples shown it is as high as 20. But in fact the greatest difficulty is to find out the correct reference length to divide (or to compare, which, for example, applies to the posts rakes). Ideally, you simply need to check them all, as I mentioned in entry #12. Note: the first three examples show designs sporting the so-called double master frame, which are not applicable to your particular project of a boat, however the other details are or may be analogous.

What is the origin of the tables of offsets? Not a previously produced design drawing? 🙂 As a curiosity — in a work published in 1711, William Sutherland proposed a new way of designing. He cited as one of its major advantages the possibility of achieving greater precision in tracing the lines compared to the traditional way, and consequently less waste of time, material and energy on dubbing.

Arthur, if you decide to investigate this at all, especially the lengthwise position of the master frame and the like, I'll just hint, just to be safe, that Rhino's command ‘divide curve by number of segments’, is very handy for this purpose.