Waldemar

Wayne, are you referring to the Baker's drawing I am currently analysing?

The next step is to recreate the lengthwise division of the hull for individual frames (room & space). The original division has not been made in an overly precise manner. However, for the aft section of the hull (i.e. behind the midship frame) the intended spacing had to be 1 foot 11 inches. For the fore section I have chosen the same spacing, but it is also possible to have a slightly different spacing where one of the lines coincides with the geometric start of the keel, as seen in the original drawing. Source works leave not the slightest doubt that the different spacing could have been used independently for the aft and fore sections of the hull. In practice, any rather small difference seemed to make little difference. It is also noteworthy that the division in both directions started not from the midship line, but from the corresponding surface of the floor timber. This means that the midship frame was to be made up of one floor timber and four futtocks, two to each side.

It seems that this observation is perfectly in line with what has been already written about hollowing curves (deadrise) in my thread on Sutherland's hull design methods. Luckily, no need to randomly guess at the particular method employed by Baker, as all the determining factors are already clearly seen on his draught itself.

Before we go any further, I am posting a corrected sketch of the one shown in my post #8. As it turned out, the rising line of the floor (i.e. that in the profile view) was also constructed as a single arc, from bow to stern. This meant that its tangent point with the keel line fell slightly behind the midship frame (shown on the sketch). Alternatively, when drawn as passing through the three points (on stempost, sternpost, keel/midship frame intersection), it slightly cut the keel line. In practice, however, there is little dimensional difference between those two variants. I have sometimes given two values when dimensioning the same element. The second value, given in brackets, is written on the original plan, and is usually not quite accurate. Now it is perfect.

Jaager, it is best to hold off formulating hypotheses and drawing conclusions until the reconstruction is complete, unless you are prepared for quite a surprise. Now it has to be said that this drawing, or generally the Baker's work, has little or nothing to do with the Dutch, but rather with someone else. But more about that later in this thread.

Thank you for your contribution, Mark. Obviously, I don't even have a chance to fill the gap left by the two scholars you mentioned, but I will try my best to at least give a decent technical interpretation of this one iconic plan.

Druxey, please have a look at the zoom below. My measurements show quite accurately 3 inches for the deadrise at this place.

This is followed by the guiding rails, extremely important for this method: those of the breadth and of the floor. These rails have been drawn in the original plan in the simplest possible way as arcs of circles. The height of both ends of the floor line is quite typical for the period. In the middle this line touches the keel. Despite this, it is clear from the midship frame profile featuring a deadrise, that this is a drawing mistake or just simplification. Surprisingly, the position of the midship frame does not coincide with the greatest width of the ship.

According to the most refined scale on the left-hand side of the drawing, the keel length (K) of the ship is 60 feet. The (design) hull breadth (B) is 24 feet. All dimensions are in feet, and in parentheses are given their proportions relating to other parts of the ship, as found in the most logical or expected way. The first step was to define the axial elements of the skeleton. The sketch is self-explanatory, except for the vertical of the stempost rake, which was made double to enable its drawing construction. The upper arc of the stempost is tangent to the lower arc in the point A, and passes through the point B.

Thank you again Wayne. Indeed, I have found most of these studies useful in my reconstructions. I now intend to actually analyze this particular plan by Baker using graphical methods. And no, there will be no comparisons to cod's heads and mackerel's tails in my reconstruction. 🙂

Thank you for your input Wayne, but this is why someone should finally do it, or at least attempt to.

Below is a reproduction of the oldest ship plan of English origin, taken from the manuscript Fragments of Ancient English Shipwrightry by Mathew Baker (British Archives). This drawing is widely reproduced and more or less extensively commented on in numerous modern publications, but so far I have not yet encountered a detailed analysis of it, especially by graphic means. The plan is attractive for at least two reasons: it is complete in the sense that it would have already enabled the construction of the ship's hull in full scale by shipwrights. Secondly, its historical potential is considerable, as it represents a method of design different from the methods known from the later English treatises and manuals such as Harriot ms, 'Newton' ms, anon. ms 1620, Bushnell and Deane ms. Apart from other considerations, this very plan is a further indication of where to look for the roots of the methods then creatively developed by English shipwrights. The drawing contains quite a few inaccuracies characteristic of hand drawing. Reproducing errors of this kind as well as a simple redrawing misses the point, so in the following reconstruction I will rather look for the intention of the designer, trying to find as many regularities, proportions and interrelationships as possible.

It must be done by manual correcting the longitudinal guides ends. This correction should start more or less equidistant from the posts to get decent results. Quite lengthy process, but perfectly possible. And, in a way, just like in real boatbuilding techniques.

Here's my method for clinker strakes. Actually, I have used its simpler variant, as my surfaces were much flatter and more or less vertical. It means that in step 4 I have made even dividing in vertical direction, and not along the frame profile. Consequently, in step 5 my cutting surfaces were horizontal, and not perpendicular to the surfaces to be cut. step 1: two frame surfaces, inner and outer step 2: frames created, outer surface left for the next steps step 3: outer surface offset by roughly the plank thickness step 4: dividing plan for both surfaces (must follow the run of the strakes set beforehand) step 5: creating cutting surfaces step 6: both surfaces split step 7: lofting the inner surfaces of the strakes step 8: inner surfaces of the strakes offset as solids step 9: (Boolean) cutting edges of the strakes (optionally) step 10: (Boolean) cutting of the frames

I think I know what is involved. It's the same with my model. It's just not possible to get the course of the strakes in such a way that they have a perfect course in every projection. But the same effect must have been in real ships.

Kevin, I am about to describe my method of shaping clinker planks, but need some time to prepare the accompanying graphics.

Pipes could in theory be the ideal tool, but in practice they generally do not work well. Those with a fixed radius can only produce rectangular boards, i.e. having parallel edges (not very useful as you know). And those with variable radii are usually generated by software with a less than acceptable shape that is very difficult or impossible to correct. Not a bad disaster. The most reliable method I've found so far is to divide the station/frame profiles by an equal number to get a run of planks. But not all the way through, as this usually has to be done segment by segment, with each segment covering only a few runs of planks. Alternatively, from one wale to another (externally) or from one deck to the next (internally). Still, quite a lot of manual adjustments are usually needed.

Kevin, your boats look gorgeous both painted and unpainted. When it comes to lofting planks in CAD, I find it the most difficult task to do on a regular/systematic basis. Relatively flat surfaces are easy, but with heavily convex shapes insurmountable complications arise. Some improvisation is then needed. Perhaps Tabycz would have something to say....

Better yet, please make it quick so I can peep how you'll handle the rigging. 🙂

A full 3D reconstruction is intended or just the boat's hull?

Very nice. What (historical) sources have you used, if any?

Back to Sutherland and the Restoration yacht. Below is a sketch showing in detail how the frames of the double conoid hulls were drawn. and all the necessary elements are there. It is difficult to imagine something simpler and efficient at the same time in terms of design method. The stern is constructed in the same way with the difference that the hollowing radii are variable and equal to the corresponding radii of the lower conoid, with the exception of the very last frames, where hollowing radii are equal to the corresponding upper conoid. That's it.

In order to show something concrete again in this thread in as clear a graphical way as possible, and perhaps persuade Mark to design an Elizabethan era ship himself, I present below a relatively easy way to do it. It can be useful for graphical as well as non-graphical and partly graphical methods of ship design. Precisely, it is about achieving the most important and at the same time conceptually most difficult shape of the submerged part of the hull. This is one of the many variants of the moulding method (hauling down/pulling up), giving pre-designed frames along the entire length of the hull. A computer is not necessary as you can draw by hand, but it speeds up the work considerably and improves precision, as can be seen in the accompanying graphics of a comparative nature. This is why the sketch of a merchant ship circa 1600 kindly provided by Druxey will be used as a starting point. For the sake of better comparison, I have retained most of the parameters adopted in the original sketch, apart from a few elements that I have seen fit to modify. One must start by establishing the overall proportions of the hull, the shape of the axial skeleton elements and two guides of the most significant importance – the rising/narrowing lines of the breadth and the floor. This is not difficult, but it is best to make use of works on naval architecture, shipbuilding contracts and shipwrecks. However, as I wrote earlier, this is beyond the scope of this thread, as I would also like to do other things in my life besides quoting the contents of other works. Next you need to work out the shape of the main frame. Basically, I used the original design, but added a deadrise so that when the limber holes are cut out, the bottoms are not weakened, and bilge water can flow more easily to the keel and pumps. I have also reduced the radius of the all-important futtock sweep to get larger capacity and to the limits indicated in the 'Newton' manuscript. If anyone has read this thread from the beginning and has even a basic understanding of geometry, the attached sketch is self-explanatory. It must be stressed, however, that it is not necessary, or indeed allowed, to use waterlines and diagonals to correct the hull lines, as this will only deform the shape obtained by the historically correct means. There is no mention of the use of these design tools in early English works on shipbuilding (Baker, Newton, Harriot, anon. 1620, Bushnell), and they only begin to appear on plans in the second half of the 17th century. Properly applied moulding method together with a properly selected main frame shape almost guarantees correct, smooth hull surfaces. Obtained shapes may be not absolutely perfect, but this is an inevitable, inherent limitation of this method. Hollowing templates lines ('moules') were added in a systematic way along the entire length of the hull. Their shape is described in the 'Newton' manuscript (see my post #57), and the method of application in my post #7. I guarantee that a professorial degree or even an engineering degree is not needed for this. It is also safe to say that most would not be able to cope, at least not immediately. I invite you to experiment for yourself. Enjoy!

We are thinking along similar lines, Jud. Unfortunately, my time is limited, and I now prefer to focus on lesser known or obscure aspects of period ship design. If a broader context is needed, there are a great many works on naval architecture available.

Yes Jud, you are absolutely right. This thread is not so much about why hulls were shaped one way or another, but rather how this was achieved. However, this equally interesting subject can also be successfully pursued in most early works on shipbuilding or naval architecture. And it probably goes without saying that the two issues are indeed very closely linked.