No original plans of any ship from the Age of Discovery exist because shipwrights did not use plans drawn on paper or parchment. The only plans were in the master-shipwright's head, and the ships themselves were built by eye.
Replicas or reconstructions of several Age of Discovery ships have been built in recent times.They look fine and romantic, but few of them can sail anything like as well as the original ships. There is clearly something wrong with the way we understand the design of these ships.
From the outset, one of the stated objectives of the Duyfken Replica Project has been to produce a reconstruction that sails well enough to emulate the achievements of the original Duyfken.
Research to reconstruct the design of Duyfken, a Dutch jacht built at the end of the 16th-century and used for exploratory voyages, drew on five major types of data.
The first objective in the Foundation's research was to learn to draw ships with the right external style and appearance. Foundation researchers compiled an extensive catalogue of reproductions of Dutch marine art from the time of Duyfken and used mathematical and statistical analysis to describe and find typical forms and ratios of proportions. This goes by the rather grand name of "Morphometric Analysis of the Iconography".
Although this analysis was aimed primarily at learning the style rather than the technical design of the ships, we began to notice that some proportions shown in the iconography consistently indicated a hull-form very different from ships of half-a-century later.
In the absence of any plans for a ship of this period there have been a number of theoretical (on paper) reconstructions designed by using the relatively narrow and box-like hull-form of the late 17th-century, whence plans are available, and combining this with the high-stern and large billowing sails of the 16th-century galleon. The results could be disastrous if tried at full-size.
Following clues in the iconography, we began tentatively to move towards a design with more beam, and with longer and sharper bow and stern; but without questioning the shallow boxy cross-sectional shape. At each phase, reports on the research were sent to experts in the Netherlands for comments and criticism. A very positive response came in the form of confidential information about the on-going under-sea investigation of a circa 1590 shipwreck in Dutch waters which showed very strongly the long and relatively sharp bow and stern that we had tentatively reconstructed. Furthermore it provided evidence for an unexpectedly sharp cross-section shape (hollow garboards). Other evidence has supported this interpretation. It is the solid evidence of archaeology that lets us see what other evidence was hinting.
The proposed design, a broad-beamed but sleek design, has been tested by computer modelling (using the Western Australian developed Maxsurf program) and the results are encouraging, showing a design with good stability and able to maintain good average speeds even in light conditions, in keeping with the historical evidence.
Now the replica Duyfken has proven the research a success. The Duyfken Foundation has a design that sails well, reinforcing archival research which shows shows that the original ship was exceptional - often out-sailing much larger ships, and maneuverable enough to be taken close to unexplored lee-shores even during the stormy and dangerous monsoon.