HMS Pandora (1779) CAD build log

[rdsaplala]

Hi SketchupModeler,

 

Splendid work on the Pandora, thanks very much for the tutorial  

I've long been itching to try out building this particular ship and draw my own bulkheads by re-scaling the AOTS plans to 1/64 and offsetting each station by 1.5mm inward to make up for planking thickness, sketch-up seems to be a fairly nice and economical option for me to try out my plan. I will be watching your build with great interest  

[Decoyman]

 

I've long been itching to try out building this particular ship and draw my own bulkheads by re-scaling the AOTS plans to 1/64 and offsetting each station by 1.5mm inward to make up for planking thickness

 

I don't think you need to offset the lines: as drawn they represent the outside of the frames/inside of the planking.

 

Rob

[SketchupModeller]

Aldo,

 

One thing to keep in mind is that the line drawings (the ones I've used so far) are already drawn to the inside of the planking/outside of the frames, so you won't need to offset.

 

Edit: Looks like Rob said exacly the same thing.  Great minds think alike!

Edited April 22, 2013 by SketchupModeller

[rdsaplala]

Ah, that's great to know, thanks very much for the info, guys

[EdT]

A very interesting project I look forward to your progress with it.

 

It my be helpful - perhaps you already know this - that Pandora was a member of Porcupine Class of 1776 - a Williams design. I mention this because The Shipbuilders Repository 1788 uses Porcupine as its example for a 24 gun frigate, which means that all the information included will be specific to Pandora as well. This includes the Table of Bodies and all the scantlings (sizes of every timber) - including those that are ship specific.

 

If you can get your hands on a copy, it may be helpful.

 

Ed

[Dida]

This is my CAD build log for HMS Pandora.  I am using the free version of Sketchup (with a few add-ons) to construct the digital model....

Hi! Please, can you tel us which add-ons you use in this project?

Thank you!

[qwerty2008]

I love skechup its so easy to use I have made many models on it (mostly houses) since I found it in 2008. I once built a small Chinese junk using a a similar approach to what you are using it was a lot of work and I never got to the mast and rigging.

[SketchupModeller]

A very interesting project I look forward to your progress with it.

 

It my be helpful - perhaps you already know this - that Pandora was a member of Porcupine Class of 1776 - a Williams design. I mention this because The Shipbuilders Repository 1788 uses Porcupine as its example for a 24 gun frigate, which means that all the information included will be specific to Pandora as well. This includes the Table of Bodies and all the scantlings (sizes of every timber) - including those that are ship specific.

 

If you can get your hands on a copy, it may be helpful.

 

Ed

 

Ed,

 

I wasn't aware of that book, but thanks for letting me know.  It sounds like that is exactly the sort of information I should be using, but unfortunately I'm not able to get access to a copy.

 

Hi! Please, can you tel us which add-ons you use in this project?

Thank you!

 

Dida,

 

These are the add-ons I've used most frequently:

 

Curviloft  (available here: http://rhin.crai.archi.fr/rld/plugin_details.php?id=674) is used to generate a smooth, curved surface.

 

Bezierspline (available here: http://rhin.crai.archi.fr/rld/plugin_details.php?id=34) is used to generate a number of different types of spline curves.

 

Joint Push Pull (available here: http://rhin.crai.archi.fr/rld/plugin_details.php?id=719) is used to offset a curved surface by a defined distance (for example, adding in planking that is X inches thick).

 

SU2KT (available here: http://rhin.crai.archi.fr/rld/plugin_details.php?id=423) is used to export the Sketchup file for rendering with Kerkythea.

[thowen]

Thanks for your info about the add-ons.
 

Very helpful.

 

Kind regards

Thomas

[Richard50]

I'd love to get into CAD, but where do you start, and what software is required? Thanks in advance for any help.

[Nirvana]

Jim,

 

The software used to create this ship Pandora, is called SketchUp available in two version, free version and paid pro version.

It's shallow learning curve but with a lot of advance features.

I have used it for many years.

[Richard50]

Jim,

 

The software used to create this ship Pandora, is called SketchUp available in two version, free version and paid pro version.

It's shallow learning curve but with a lot of advance features.

I have used it for many years.

Thanks for the tip, I've downloaded the file; just need to earn how to use it.

[Dida]

Thank you for the links to the add-in site. Very useful pages.

[JohnMGD]

SketchupModeller,

 

I just started learning SketchUp, and I'm also a ship modeller. My question, would it be possible to make a kind of a tutorial of your 3D HMS Pandora build ?? In this way we could learn about how to use SketchUp for our hobby too.

Would appreciate it very much, you are doing an awesome job !

 

John.

Edited November 29, 2013 by JohnMGD

[the learner]

Sketchup where are you? what happened to the  progress of your facinating build

[SketchupModeller]

Part 6: Getting ready to form the hull

 

After a bit of a delay, I'm back.

 

Back on page 2 (and almost a year ago!), the stations were defined.  The stern needs to be defined, and the bow and topsides still need a little work before the surface can be skinned.  These will be the subjects of today's post.

 

The edges of the transom, counter, and stern timbers were drawn in by tracing these timbers from both the body and sheer plans (purple lines) and projecting to an intersection, as shown below.  The final edge is highlighted in red.  The aft edge of the wing transom (green line) was traced from the framing plan, and the blue line follows the rabbet on the sternpost.  Note that the last few stations have been hidden for clarity.

 

Next, lines were drawn in to define both the lower and upper edges of the hull's shape.  The lower edge is simplest, as it merely connects the bottom ends of the station lines.  Forward of the foremost station, this line continues up the stem, so that it defines the profile of the hull as seen on the sheer plan.  Later, this line will be used to form the rabbet.  The point at which this line terminates is taken from the sheer plan.  Only the forward portion is shown below, but this line (blue) continues all the way aft.

 

Most of the upper edge was drawn in using the same method of connecting station to station and tracing from the sheer plan when needed (for example, at the scrolls).  Finally, a curve was drawn in to connect the first few stations and the forward line described above.  For this, I tried a number of different splines and curves included in the BezierSpline plugin until I found one that looked reasonable.

 

The end result of all of this was the construction of a number of closed loops that together will make up the surface of the hull.  The next post will discuss how to create this surface.

 

[Don9of11]

Ed,

 

I wasn't aware of that book, but thanks for letting me know.  It sounds like that is exactly the sort of information I should be using, but unfortunately I'm not able to get access to a copy.

 

 

Dida,

 

These are the add-ons I've used most frequently:

 

Curviloft  (available here: http://rhin.crai.archi.fr/rld/plugin_details.php?id=674) is used to generate a smooth, curved surface.

 

Bezierspline (available here: http://rhin.crai.archi.fr/rld/plugin_details.php?id=34) is used to generate a number of different types of spline curves.

 

Joint Push Pull (available here: http://rhin.crai.archi.fr/rld/plugin_details.php?id=719) is used to offset a curved surface by a defined distance (for example, adding in planking that is X inches thick).

 

SU2KT (available here: http://rhin.crai.archi.fr/rld/plugin_details.php?id=423) is used to export the Sketchup file for rendering with Kerkythea.

 

Thanks for the plugins. I downloaded the newest version of Sketchup and I am not able to install these I think because Sketchup is looking for rbz files and these are rb files. Has anyone else have trouble installing these scripts?

[SketchupModeller]

Don - I'm still using Sketchup 8.  From Sketchup 2013, a new system of plugins, the Extension Warehouse,  was introduced.  This is probably where the problem you're having originated.  Two articles from the Sketchup site that discuss adding plugins/extensions to Sketchup 2013 and 2014 via the Extension Warehouse and manually installing .rb files are here:  http://help.sketchup.com/en/article/38583 and http://help.sketchup.com/en/article/3000050.

 

Hopefully this will help.

[SketchupModeller]

Part 7: Starting Over

For the past few months, I have been working ahead at skinning over the surface and cutting out frames, and starting on the gun deck beams and framing.  As shown below, this is considerably farther ahead than the previous entry here.

 

However, a few recent developments have made me decide to terminate work on that version and start over.

 

First, further research showed a number of significant errors.  Most importantly, I had assumed that the frames were square to the load waterline, and drawn them in as such.  Reading through the Shipwright's Vade-Mecum, and watching other logs. I learned that the frames should be square to the keel.  This means that the shape of the body as drawn is incorrect.  Next, I purchased a copy of Scantlings of the Royal Navy, which showed that a number of my measurements were woefully inaccurate (for example, the drafted keel was sided 4 inches too large, and the toptimbers were sided 3 inches too small).  My next attempt will be heavily based on the dimensions given in the Scantlings book.

 

At about the same time, I made a decision that the CAD model would (eventually) be used as a basis for a POF model. For this, I would need to increase the resolution of the hull (the previous version, while smooth enough for computer rendering, would not be adequate for use as a pattern, and certainly not at a scale of 1:48 or larger).

 

Finally, I would like to ask any member with a copy of Steel's Naval Architecture or the Shipwrights Repository if they would be able to PM me a copy of the table of the body of the 24 gun frigate, as having that information would greatly help to accurately form the shape of the hull.

[Don9of11]

Your work is awesome! To have completed what you have done so far is amazing. Are you switching CAD programs or staying with Sketchup? I wouldn't worry too much about having to start over, it's the mark of a good shipwright and what you have learned so far will aid you in your new efforts.

[the learner]

Good to see you back looking foward to the completion of your log and inspriation to all of us nonproficient cad users

[SketchupModeller]

Part 8: Armament

 

As a starting point for the second attempt at this project, I decided to draw up the armament.  I will be using the original armament of the Porcupine class, that is 22 x 9 pdr on the gundeck and 2 x 6 pdr on the quarterdeck, instead of the armament of Pandora as sunk (20 x 6 pdr on the gundeck and 4 x 18 pdr carronades on the qurterdeck).  This is partly because my model will be of Pandora as originally planned (e.g. Pandora's Box will not be fitted), partly because I have yet to find good references giving the dimensions of carronades, and partly (mostly) because I personally find carronades brutish and unattractive.  I have chosen to use 9 pdrs of 7 feet long, and 6 pdrs of 6 feet.

 

The barrels of the 6 and 9 pdrs were drawn using General Armstrong's proportions, as given in the 1768 edition of Muller's Treatise of Artillery.  This edition is freely available from Google Books.  Detailing, especially around the cascable, was heavily based on a number of photos of period guns.  The carriages given in Muller's work seem date from the middle of the 18th century, and look to be a bit too long for the end of the century.  Instead, I used Harold Hahn's dimensions as fournd in this thread http://modelshipworld.com/index.php/topic/6059-making-gun-carriages/, which look much better (to my eye), and seem reliable, as the dimensions of the barrels match up well with Muller's work.  As an example, the 9 pdr carriage should be 63 inches long as per Muller, but only 50 inches long as per Hahn.  The quoins and carriage ironwork (shown below) are only approximations, as I have not been able to find any definitive references for these parts.  

 

The 1/2 pdr swivel was taken directly from the plans given in McKay's AotS Pandora, with a number of photos again used as references.

 

In all cases, the barrels were drawn first as a half profile, which was then rotated into a complete barrel using the 'Follow Me' tool and a circle at the muzzle end.  The touchhole and trunions were then added.  The last picture shows one of these profiles, with the position of the trunions marked out and the vertical circle for forming the 3D barrel.

[Don9of11]

Part 6: Getting ready to form the hull

 

After a bit of a delay, I'm back.

 

Back on page 2 (and almost a year ago!), the stations were defined.  The stern needs to be defined, and the bow and topsides still need a little work before the surface can be skinned.  These will be the subjects of today's post.

 

The edges of the transom, counter, and stern timbers were drawn in by tracing these timbers from both the body and sheer plans (purple lines) and projecting to an intersection, as shown below.  The final edge is highlighted in red.  The aft edge of the wing transom (green line) was traced from the framing plan, and the blue line follows the rabbet on the sternpost.  Note that the last few stations have been hidden for clarity.

Pic 6.1 - Stern lines.png

 

Next, lines were drawn in to define both the lower and upper edges of the hull's shape.  The lower edge is simplest, as it merely connects the bottom ends of the station lines.  Forward of the foremost station, this line continues up the stem, so that it defines the profile of the hull as seen on the sheer plan.  Later, this line will be used to form the rabbet.  The point at which this line terminates is taken from the sheer plan.  Only the forward portion is shown below, but this line (blue) continues all the way aft.

Pic 6.2 - Forward lines.png

 

Most of the upper edge was drawn in using the same method of connecting station to station and tracing from the sheer plan when needed (for example, at the scrolls).  Finally, a curve was drawn in to connect the first few stations and the forward line described above.  For this, I tried a number of different splines and curves included in the BezierSpline plugin until I found one that looked reasonable.

 

The end result of all of this was the construction of a number of closed loops that together will make up the surface of the hull.  The next post will discuss how to create this surface.

Sketchup, when you created the stem, keel and stern post, did you incorporate any taper or did you make the same width? I look forward to seeing how you run the rabbet and your hull surface.

[kyle]

I own the Anatomy of the HMS Pandora book, but cannot seem to get an accurate scan of the plans to my computer. Is there a way maybe you could send them to me? Yours look great...

[Ben752]

On 8/9/2014 at 4:46 PM, SketchupModeller said:

Part 8: Armament

 

 

 

 

 

 

 

 

As a starting point for the second attempt at this project, I decided to draw up the armament.  I will be using the original armament of the Porcupine class, that is 22 x 9 pdr on the gundeck and 2 x 6 pdr on the quarterdeck, instead of the armament of Pandora as sunk (20 x 6 pdr on the gundeck and 4 x 18 pdr carronades on the qurterdeck).  This is partly because my model will be of Pandora as originally planned (e.g. Pandora's Box will not be fitted), partly because I have yet to find good references giving the dimensions of carronades, and partly (mostly) because I personally find carronades brutish and unattractive.  I have chosen to use 9 pdrs of 7 feet long, and 6 pdrs of 6 feet.

 

 

 

 

 

The barrels of the 6 and 9 pdrs were drawn using General Armstrong's proportions, as given in the 1768 edition of Muller's Treatise of Artillery.  This edition is freely available from Google Books.  Detailing, especially around the cascable, was heavily based on a number of photos of period guns.  The carriages given in Muller's work seem date from the middle of the 18th century, and look to be a bit too long for the end of the century.  Instead, I used Harold Hahn's dimensions as fournd in this thread http://modelshipworld.com/index.php/topic/6059-making-gun-carriages/, which look much better (to my eye), and seem reliable, as the dimensions of the barrels match up well with Muller's work.  As an example, the 9 pdr carriage should be 63 inches long as per Muller, but only 50 inches long as per Hahn.  The quoins and carriage ironwork (shown below) are only approximations, as I have not been able to find any definitive references for these parts.  

 

 

 

 

 

 

 

The 1/2 pdr swivel was taken directly from the plans given in McKay's AotS Pandora, with a number of photos again used as references.

 

 

 

 

 

 

 

 

 

In all cases, the barrels were drawn first as a half profile, which was then rotated into a complete barrel using the 'Follow Me' tool and a circle at the muzzle end.  The touchhole and trunions were then added.  The last picture shows one of these profiles, with the position of the trunions marked out and the vertical circle for forming the 3D barrel.

 

 

 

 

I found a good source of carronade and long gun information in this book: https://www.amazon.com/Arming-Fleet-U-S-Ordnance-Muzzle-Loading/dp/0870210076/ref=sr_1_2?ie=UTF8&qid=1505675943&sr=8-2&keywords=arming+the+fleet.

 

It's not limited to post 1812 weaponry and contains numerous drawings, details on carriages, rigging, etc.

 

 

 

 

[Nirvana]

Fascinating virtual build log.

[Sailor1234567890]

No updates lately? I wonder how the project went?

[JohnMGD]

Yes, I would also like to know how the project went with HMS "Pandora" ??? It is a long time ago (2014) that the last entry was.