Naseby 1655 - reverse engineering the ship model

I have just returned from a long period of travel and caught up on this thread. Some brilliant work here, and fascinating discussions. We will need to go through a similar process in reconstructing the original form and design methodology for Vasa, which is now somewhat distorted and shrunken, so the process Waldemar has illustrated is extremely helpful.

Fred
 
Waldemar has taken a scientific approach to analyzing the lines of the Naseby 1665 ship model along with known information.
Using CAD mechatronic analysis tools helps to look at numerous what if types of analysis to see what fits best in filling in the missing pieces of information as well as verifying the methodologies used at that time.
This were the power of CAD mechatronic analysis shines the brightest.

Note that the information input into the system has to be top notch, which means the analysist also has to know what they are doing.
The analysist needs to not only understand the subject matter but also the nuances of the tools he is using.
Otherwise no matter how great the tool may be, its results could be worthless.
The old adage "garbage in equals garbage out" comes into play here.
 
DonatasBruzas said:
Hello,
I understand Fred is referring to the Niklas Eriksson book "Riksäpplet - Arkeologiska perspektiv på ett bortglömt regalskepp" published in 2017. On this book the author is referring to the Glete's work as a source of information about the model (page 105) when discussing the similarity to the Riksäpplet. Both Glete and Eriksson admit that the dimensions of the model were taken from the plan created in the 1930s by Hugo Åkermark. Now, when we have a 3D photogrammetric model, it is not very difficult to see that the plan does not portray the actual model very closely.
My version would be this:
Sheldon could use the enlarged ship of the 1654 group (Naseby) as a source when designing ships in Sweden. In that situation the Ö 3 may stand for a design proposal of a ship influenced by the Naseby (similar dimensions) but different (beakhead?, upper decks configuration, galleries). The Riksäpplet is a further modification of this concept with altered dimensions but similar decorations etc.
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Hallo @DonatasBruzas
we wish you all the BEST and a HAPPY BIRTHDAY
Birthday-Cake
@- Waldemar - hope it is ok to use your topic for these greetings - and brings this highly interesting topic up in the list
 
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I watched the video. I completely fail to understand why Kroum talks about some dimensional inconsistencies, when the correspondence between the proportions of the Ö3 model and the dimensions of the Naseby 1655 is downright perfect. But these are perhaps normal methods in disputes when there are differences of opinion, and which in a way I am already starting to get used to.

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DARIVS ARCHITECTVS said:
If only Peter Pett had these tools. . . .
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My approach here is to limit myself to the mathematics as known in the century of Pett. Generally the Pythagorean theorem and it's applications is all you need to solve the largest part of problems. I believe that they (Pett, Deane, Shish, Sheldon and the builders from a generation before at least) did this algebraically as well as presented in the 'Dimensions of the Modell of a 4th Rate Ship' by Shish. This could explain why they didn't need to use scale plans and why the treatises put so much emphasis (f.e. a half of the Deane's Doctrine) on how to solve general geometry problems computationally.
 
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DARIVS ARCHITECTVS said:
If only Peter Pett had these tools. . . .
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Indeed, fantastic, "sexy" stuff. For me, perhaps the most striking thing about Donatas' renders is the colour feast, and the best thing is that it shows exceptionally well how many geometric parts the frame contours are actually made up of. And all this effort (on the part of the designers) for getting a perfectly smooth hull shape without using diagonals and waterlines.

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A list of tools you need to calculate a ship hull - an outline for a Treatise or a Doctrine:

Calculate a sagitta from a half-chord and a radius.
Calculate a radius from a sagitta and a half-chord.
Calculate a half-chord from a sagitta and a radius.
Mezzaluna (two types) from a radius and a distance value divided by a whole distance.
Mezzarola (implemented but not needed for the Sheldon's ship)
Deck beam camber from a radius and a distance value divided by a whole distance.
Calculate a distance between two points.
Find a point on a line, nearest to another point, not on the line.
Find the intersection points of two circles.
Find the point where two circles touch.
Find a circle which is tangent to a given circle at a specific location and goes through a given point.
Get a concave reconciling circle from two given circles and a radius.
Get a reconciling circle from two given circles and a radius to form a S shape.
Get intersections of given circle and line.
Get circles tangent to given circle and line.
Find on a circle a point nearest to a given point.
Get a circle through three points.
Intersect two lines.
Get an ellipse through two points and a tangent coefficient.
Get a parabola through three points.

and for the in/out dimension to be removed or added (if concave) to the outside points' radii - a monospline through the known values in this case:
1 ft 5 in + deadrise @ keel
1 ft 5 in @ floor
10 in @ maximum breadth
4 in @ top
 
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DonatasBruzas said:
I am back building the hull generating script.
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I'm curious to see if you decide to embark on a similar programming venture for the Ö 6 model. This model was also designed using the English moulding method, but in an interesting variant probably unknown until now. For the time being, however, I had to make a diversion myself and interrupt the development and presentation of this material in order to finalise(?) the North Continental/Dutch thread.

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-Waldemar- said:
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I'm curious to see if you decide to embark on a similar programming venture for the Ö 6 model. This model was also designed using the English moulding method, but in an interesting variant probably unknown until now. For the time being, however, I had to make a diversion myself and interrupt the development and presentation of this material in order to finalise(?) the North Continental/Dutch thread.

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We will see how many of difficult to implement devices you will put on the drawings.
These things like the reducing devices for the radii, the large circle arc based adjuster for the floor radius fore, the line controlling the upper 'wings' or the lower hollowing curves aft, the composite hollowing templates were some of the more difficult for me to create.

Currently I see several directions for the further work.
1. Add more devices/curve types (logarithmic, geometric progression etc.) to the existing set and test with other ships.
2. Implement more details to the ship (would you like to see carlings, bulkheads, stern framing, headrails etc.?).
3. Implement a later model with diagonals and geometrically constructed progressions.

Now I have a script which needs some meticulous work to translate drawings into a written form (like describing what you see by using a limited set of 'words'). It does not have any validation, so it would not tell you that your circles could not be reconciled if they radii were to small. But then it also does not require you to do any mathematical calculations at all - it will give you sets of 3D points automatically :)
 
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