Skipjack Kathryn 1901 by Jsk - 1/72 scale - Card

[Jsk]

First, I’d like to wish you all a happy New Year. May Dame Fortune grant you peace, contentedness and many, many hours of happy modeling time!

 

Now, a little back story: Kathryn and I have quite a lengthy relationship. Well, frankly I’ve been infatuated with her for years but she doesn’t know I exist. (But the story of my adolescence doesn't need to be retold here!) I started designing a card model of the skipjack Kathryn in 2016 based on the HAER papers available from the US Library of Congress (https://loc.gov/pictures/item/md1454/). I refer you to an old build log I did at PaperModelers.com: https://www.papermodelers.com/forum/design-threads/37710-1-100-scale-chesapeake-skipjack.html.

 

Life happened, other hobbies took priority, and I drifted away from model building. Meanwhile, the unfinished Kathryn sat ignored on the mantel in my ‘man cave’. But I didn’t completely forget about my old flame. One of the competing hobbies is the open source flight simulator ‘Flight Gear’. Being a contrarian, I wanted to use it to simulate sail boats. So I enhanced the basic virtual model of Kathryn, ported her into Flight Gear and started (with the help of the Flight Gear forum members) to tinker with the configuration files in order to ‘sail’ the virtual seas. I called it ‘Float Gear’. I refer you to the Flight Gear forum if you’re interested in that unfinished journey: https://forum.flightgear.org/viewtopic.php?f=4&t=40606

 

Now that the worm has turned yet again and my interest in ship models has resurfaced I’d like to revisit the old girl yet again. One thing I want to accomplish is a larger scale. The original card model was at 1/100 scale—common enough for card models but a bit small for my eyesight these days. I wanted to go to 1/72 scale to match the Viking ship I recently finished.

 

I also wanted to try out a different electronic workflow. I still enjoy using Wings3d (www.wings3d.com) to create virtual models and the original model is still valid. However, back in ’16 I wrote my own script to extract UV coordinates from the model and output them in SVG format in order to create the patterns for card modeling. UV mapping was (and remains) a tedious process in Wings3d. And, UV coordinates don’t necessarily reflect the true shape of the model’s surfaces. Let’s just say it was more work than it was worth. Making revisions was a nightmare. However, over the intervening 7 years other tools have become available. I recently came across a plug-in for Blender which ‘unrolls’ a 3d model. I want to explore that option and see if it really is usable for card modeling or if it is still too limited. So far, the signs are good.

 

In future posts I intend to document how I’ve used Wings3d, Blender and Inkscape to design a card model of Kathryn. While I’m not entirely certain this experiment is going to work, I’m fairly convinced that—at least for a fairly simple model—the real challenge is going to be my rather limited modeling experience.

 

But for now I’ve accomplished enough with a test build to show some progress. The pictures pick up after I’ve cut the longitudinal spine and various bulkheads out of 1mm chipboard. The keel/spine is then doubled to give a final thickness of 2mm. I have explored having these pieces laser cut by a third party but I finally decided I was putting the cart before the horse. I think I need to ensure the design is good before committing to that. After all, I want to make sure it's functional before going for efficiency and ease of construction.

 

As mentioned elsewhere there was a fair amount of warping going on with the spine and the bulkheads. Nevertheless, I dry-fitted all the components in order to assess the situation.

 

Puzzling this out it dawned on me that I had the locations of a number of the bulkheads and the spine marked on the deck piece. That was not intentional, it was just a by-product of the modeling/unrolling process. But I figured I could use those marks to ensure the straightness of the framework.

 

Then I proceeded to cut out the various side pieces. Again, the dotted lines represent the triangles of the electronic model. But as I assembled the model I found that they provided reliable guides to aligning everything.

Notice the bottle of isopropyl alcohol in the background. I had inadvertently skipped gluing the 'skin' to one of the bulwarks. This resulted in a bit of puckering since the side pieces do undergo a bit of twisting to make them fit. So... I had my first experience of using IPA to unglue things. Actually, it works pretty well. Poured a little IPA in my paint tray and used a cotton swab to apply it to the glue joints. After giving it a few moments to soak in I carefully started to separate the joins with a dental tool I keep in the hobby toolbox. I had to unglue four bulkheads to get to the puckered area. No harm done, though. The IPA did cause some of the printed ink to run slightly but it did not affect the paper at all.

 

You can also notice that Kathryn suffers from 'hungry horse' syndrome. The smaller, 1/100 scale version didn't suffer like this. IIRC, the card I'm using for the skin is 67#. Maybe 90 or 110# would be better for this larger model.

While the model in general is incredibly sturdy, the skin seems more flimsy than in the smaller model. I suppose this is due to the card having to span larger distances at 1/72 scale than it does at 1/100. You can really notice it along the sides of the hull from an end view.

 

Here's a view of both the old 1/100 and the new 1/72 scale models for comparison.

 

And finally a shot to compare sizes between the two models.

I've not yet attached the transom and it appears that I've cut the deck about 1mm too long. But I think the next step is to lay on a second layer of skin to smooth out the starving nag look. I'm not sure if I need to apply some putty and a sanding stick to smooth out the inner skin or whether that would just be extra work with no significant benefit. My intent is to make the outer layer slightly longer than the first and to arrange them so that the seams between the top and middle pieces are staggered (probably at the waterline rather than higher up as they are in the first skin). The seam between the middle and bottom will of course still be located at the chine. A second skinning will also allow me to finish up the graphics. After that I'll deal with the transom.

 

Well, that's how things sit for now.

[Jsk]

Seems like it's been more that a week since I worked on this. There have been challenges. After... I don't know how many years--15?... my color inkjet printer finally gave up the ghost. That brought me to a halt but it gave me an excuse to get a color laser printer as a replacement. (I think printers are the bane of card modelers!) I have to admit I'm not sure this printer is the best for what I want to use it for. It really produces curled prints on card stock. The paper feed is finicky, too. Oh, well. It's what I've got now.

 

Meanwhile I've been trying to recover some small competency with Inkscape and SVG. When I was finally able to print out the next round of parts I discovered that somehow my original printouts were only 96% of what was expected. It's only a test-build I keep telling myself. But I have to keep reminding myself to reduce anything as I print out since I don't want to start over from the beginning.

 

Even with the challenges I do believe the workflow will work. Wings3d (to model) -> Blender (to unfold) -> Inkscape (to arrange and color) -> print and build. The fit is not quite what I want but I think that's more on me messing things up as I learn every step of the process as I go.