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Posted (edited)

 

In the pursuit for answers, I have also decided to verify the body sections of the iconic ship Mary Rose, one of the first large vessel built in England using the skeleton method. So far, it has been assumed that the applied concept of the pre-designed frames formation in this ship was derived from some local tradition of unexplained origin, despite the fact that such a hypothesis contradicted the rationale from other historical findings and the overall picture of period shipbuilding. For more on this subject, see especially Mary Rose. Your Noblest Shippe. Anatomy of a Tudor Warship, 2009.

 

However, a quick verification of the hull lines leaves not the slightest doubt that the ship was shaped according to the Mediterranean method, and in its most advanced form, i.e. using the futtock mould rotation/tilting (I posted a little more about this method in the thread "Mathew Baker's early concept of ship hull design, ca. 1570").

 

As can be seen from the graphics below, applying the Mediterranean method allows for an excellent rendering of the frames original shape in the midship part of the ship, taking into account, of course, the distortion of the original lines for various reasons.

 

image.thumb.jpeg.f2dc20bb8eea072e5946e247892865c3.jpeg

 

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Edited by Waldemar
Posted

 

To make the method used more readable, slightly more detailed diagrams follow. For each section, the futtock template was moved vertically and horizontally (the position of the template after this operation is shown with a dashed line) and then rotated. 

 

The other sections (bends), closer to the ends of the ship, were already shaped by longitudinal ribbands. The hollowing and top timbers lines are not shown in the diagrams so as not to impair their legibility. Besides, from a conceptual point of view, these lines were of much less importance.

 

image.thumb.jpeg.9bdcfb03c268ce12328bf45da46c2b1f.jpeg

 

image.thumb.jpeg.48f0e3092305c8e5f043589f29e6c568.jpeg

 

 

Posted

 

Hi Steven, thank you for your input.

 

Well, I don't quite agree with the statements in this publication, and for me both the diagram and the text in this paper are more or less misleading.

 

It says "the English method achieves the modification of the three tangent arcs by adjusting the length of adjacent cords, known as 'hauling down' and 'hauling up' the arcs". However, this is a reversal of the process. First the arcs were brought into tangency, and only then was the resulting length of the arcs read and marked on the templates.

 

And also: "the Ibero-Mediterranean method was based on tilting the frame outward from a pivot point at the bilge" and a little further "the Ibero-Mediterranean texts used a limited version of "hauling down" the bilge arc in order to fair out the kink left at the bilge by the outward tilting of the futtock mould". He probably had in mind the description left by Lavanha, but a careful reading of this source text is not consistent with such an interpretation.

 

Methods known from English manuscripts and publications from ca. 1600–1670 allow pre-designed frames to be formed along almost the entire length of the hull, whereas for Mary Rose to achieve this effect in some regular way is only possible for the central part of the hull. The frames (bends) outside the midship part already elude such regular methods, so they had to be shaped with flexible ribbands. This feature also fits perfectly with the Mediterranean methods.

 

So, if we have historical information that Henry VIII imported Mediterranean shipwrights to build his fleet, why invent some implausible thesis about local methods originating from no one knows how or where?

 

 

Posted
6 hours ago, Waldemar said:

So, if we have historical information that Henry VIII imported Mediterranean shipwrights to build his fleet, why invent some implausible thesis about local methods originating from no one knows how or where?

 

 

The two pieces may or may not be related.  The Mary Rose (1509) exhibits some unique components of the frames that seem to not represent the Mediterranean skeleton- first construction. Barker has some interesting, and well documented, analysis concerning design methods, as do Steffy and Unger which acknowledge the similarity between northern shipbuilding and Mediterranean, but also note the important differences.

 

Being able to utilize mathematical and graphic methods to fit curves onto sections derived through other design systems is interesting, but coincidence does not equate to causality.

 

I think there are some intriquing aspects to what you are doing, however discounting the work of previous researchers, some with hands-on experience with vessels such as the Mary Rose, presents challenges. The question becomes one of cart and horse, whether the design methods known to be in use at the time period in question or the building systems were the determinant of shape, since drawings were not known to be used.

 

Wayne

Neither should a ship rely on one small anchor, nor should life rest on a single hope.
Epictetus

Posted

 

Wayne, in truth, I prefer to talk about specific issues rather than at the level of general considerations, which are unlikely to lead to firmer conclusions.

 

First of all, I do not, as you suggest, discount the work of previous researchers. On the contrary, I believe that familiarity with their work is even mandatory. As it happens, however, for the authors of the Mary Rose monograph, their interpretation of the hull shape of this particular ship is a key and probably the only relevant argument for some mysterious local conceptual tradition of frame-first shipbuilding method, albeit one previously unknown in the north of the continent. A sort of Deus ex machina.

 

Unfortunately, in analyzing the shape of the hull they made, in my opinion, the fatal mistake of assuming that "the Ibero-Mediterranean method was based on tilting the frame outward from a pivot point [placed only] at the bilge", rather than placed elsewhere. 

 

This may also be related to the incomplete definition given in the study pointed out by Steven: "The smoothing-out of the kink is called cancomo in Portuguese, desfaldar in Spanish and recalement in French". However, according to one of the source definitions, recalement is done "à faire répondre la façon du bas de l'estamenaire avec le façon du madier, en diminuant sa grande rondeur et la réduisant par une juste proportion", effectively moving the pivot point beyond the contour of the frame. The description left by Lavanha also leaves no doubt that the futtock template was not simply tilted but slided along the arc of the bilge.

 

But even taking your approach, i.e. of the "two pieces may or may not be related" kind, the degree of probability of both interpretations is quite obvious to me. So, it's not going to be easy for the authors of the Mary Rose monograph, or anyone else for that matter, to convince me of their conjecture, when they haven't even been able to present a coherent or convincing conception of the formation of the whole shape of the Mary Rose hull, as I have done.

 

 

Posted

 

In conclusion, for the above reasons, quite typical Mediterranean features were not recognised by the researchers of the Mary Rose wreck. Instead, some unspecified 'method', apparently not even suitable for reproducing the shape of the ship's hull, was hatched, which you seem to refer to in your post as 'other design system'.

 

Wayne, I'm very interested in this subject, so I'd normally ask you for the details of this 'other design system' you mention (archaeological, written, design principles, whatever), but should I?

 

 

  • 4 weeks later...
Posted

 

A graphic example below of a master frame from the mid-16th century Italian manuscript Arte de far Vasselli by Todaro de Nicolò (http://echo.mpiwg-berlin.mpg.de/MPIWG:7KTSNYA6). The scale for sliding (rotating) the futtock template is clearly visible on the bilge arc.

 

image.thumb.jpeg.6e90e9ba9b613b6def4f1fc0fca169bb.jpeg

 

 

  • 2 weeks later...
Posted

 

A similar, although much shorter scale can also be found in the shipbuilding manual written about 1600 by the Chief Engineer of the kingdom of Portugal João Baptista Lavanha. 

 

It is clear from the text description that the effect of using this scale was not to remove some kink, but to change the geometry of the frames by sliding the shown here futtock template along the bilge arc in a controlled way.

 


Waldemar Gurgul

 

 

image.jpeg.96631240b013dcfdca780d72fd483506.jpeg

 

 

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