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HMS Pandora CAD build log

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Upbeat

Wed Jun 01 2016, 04:25am

Registered Member #4774

Joined: Fri Apr 29 2016, 12:07pm
Posts: 15

Hi,
Not sure if this is the right forum section to post this build log. I am hoping to build the entire HMS Pandora (mostly off the Anatomy of the Ship Series) in CAD 3d Files first before eventually building a POF model of it.

So far I have traced some of the drawings (which is more of a guessing job than I would like due to line thicknesses and differences between different views in the book). I have then moved the water lines, buttock lines and the sectional lines into their 3D locations. Hope that is visible in the below pictures.

My plan now is to put planes at 1 feet intervals parallel to the keel line and to then have the program calculate intercept points with all waterlines, rabbet lines, bearding line, section lines and buttocks lines. This should then allow me to draw some 30+ 'waterlines' as accurate as possible (although I imagine that finding a compromise between the intercept points of the different lines will be tricky).

Once I have those new waterlines, I am then going to have the program calculate the intercept of those waterlines with the frames that I have traced/modified off the Framing Plan/and Profile of Frames from the book). I am planning to model the varying frame thicknesses and accurate spacing.

Are there any obvious flaws in my method, or something I have to pay particular attention too? Are 30 new waterlines too many to get a accurate shape?

daves

Wed Jun 01 2016, 03:50pm

Registered Member #105

Joined: Wed Jul 15 2009, 12:01pm
Posts: 3560

Are there any obvious flaws in my method, or something I have to pay particular attention too? Are 30 new waterlines too many to get a accurate shape?

30 waterlines may be a little over kill but the more you have the more accurate the shape will be.
looks like your spot on

so what CAD program are you using?

Upbeat

Thu Jun 02 2016, 02:13am

Registered Member #4774

Joined: Fri Apr 29 2016, 12:07pm
Posts: 15

It's Rhino for Mac. I'm going with 20 waterlines or so (1.5 feet apart). 30 looks to be a bit extreme. I am a bit confused about the bearding line and the rabbet line and how they interact, but hopefully I will work that out.

Is the bearding line when looked at from above flush with the widest part of the keel or is it set back to the deadwood?

[ Edited Thu Jun 02 2016, 03:03am ]

daves

Thu Jun 02 2016, 02:45pm

Registered Member #105

Joined: Wed Jul 15 2009, 12:01pm
Posts: 3560

Upbeat wrote ...

I am a bit confused about the bearding line and the rabbet line and how they interact, but hopefully I will work that out.

Is the bearding line when looked at from above flush with the widest part of the keel or is it set back to the deadwood?

when you say looked at from above are you saying looking down on the hull as if you were floating above the deck and looking down at the hull? if so you would not see the bearing line because it is a line along the side of the keel, stem and deadwood. The bearing line would be seen on a profile of the hull.

personally I do not think drawing the bearing line is necessary because it is nothing more than the inner edge of the planking. The rabbit line is the outer edge of the planking and the inner edge is the bearing line.

[ Edited Thu Jun 02 2016, 03:05pm ]

daves

Thu Jun 02 2016, 03:11pm

Registered Member #105

Joined: Wed Jul 15 2009, 12:01pm
Posts: 3560

oops I forgot the drawing I tried to edit the last post but could not figure out how to add an image. anyhow there is no need to include a bearing line as you can see it is nothing more than the edge of the planking where it rests against the keel, stem and deadwood

Peter Foele

Thu Jun 02 2016, 07:00pm

Registered Member #4491

Joined: Mon Sep 22 2014, 01:09pm
Posts: 142

That is about the clearest explanation I have seen so far. Cheers for that Daves.
Slainte
Peter

Upbeat

Fri Jun 03 2016, 02:00am

Registered Member #4774

Joined: Fri Apr 29 2016, 12:07pm
Posts: 15

That picture helps in understanding. So areas where there are three 'parallel' lines very close to each other in the plan would be the Rabbet, Inner Rabbet and Bearding Line if I understand it right.

Is the black line in my first picture above towards the stern part of the bearding line? I think I understand the Rabbet and Bearding lines at the bow and in the square frame area, but I am struggling to make sense of it towards the stern, CANT frame area.

The Cant frames are attached to the Deadwood which is thinner than the keelson, that part I think i get. But what does the 'interface' look like at the lowest point of the Cant frames at the stern end? I'm struggling to visualize the planking at the lowest end of the Cant frames.

I hope my question is understandable. I've tried looking at photos of build logs but still couldn't figure that section out.

[ Edited Fri Jun 03 2016, 05:34am ]

daves

Fri Jun 03 2016, 05:41pm

Registered Member #105

Joined: Wed Jul 15 2009, 12:01pm
Posts: 3560

Posted: Thu Jun 02 2016, 09:45PM
That picture helps in understanding. So areas where there are three 'parallel' lines very close to each other in the plan would be the Rabbet, Inner Rabbet and Bearding Line if I understand it right.

correct

Is the black line in my first picture above towards the stern part of the bearding line? I think I understand the Rabbet and Bearding lines at the bow and in the square frame area, but I am struggling to make sense of it towards the stern, CANT frame area.

correct that black line is the bearing line at the stern

The Cant frames are attached to the Deadwood which is thinner than the keelson, that part I think i get. But what does the 'interface' look like at the lowest point of the Cant frames at the stern end? I'm struggling to visualize the planking at the lowest end of the Cant frames.

where the bottom of the stern frames sit against the deadwood a shallow recess is cut into the side of the deadwood and the frame is set into the deadwood. This is called boxing. I will look for an example of this to post.

The bearing line defined is the point where the inside edge of the planking rests or "bears" against the backbone of the ship, like this

the blue line is the rabbet and the red line is the bearing line. At the stern and cutwater the bearing line sits farther back from the rabbet because the plank sits flatter against the backbone at these points.

the reason for drawing the bearing line is because the bottom of the frames stop at the bearing line see this example

http://modelshipbuilder.com/e107_plugins/forum/forum_viewtopic.php?1052.0

The blue arrow is pointing to the same place the black line on your drawing is

Upbeat

Fri Jun 03 2016, 09:52pm

Registered Member #4774

Joined: Fri Apr 29 2016, 12:07pm
Posts: 15

Hi Daves, thanks for the clarification.
Is it possible that in HMS Pandora the rabbet and bearding lines stay parallel at the bow rather than diverge as is shown in your diagram?

I had seen this picture of the great work by Gene Bodnar below before and it makes sense to me if the deadwood has the same thickness as the keel itself, but how should the taper look when the deadwood is thinner than the keel?

Sorry for all the questions. I just feel like this is an obstacle that i am really struggling to visualize clearly