The Ship Model Forum

Greetings all,

As you may know, if you have been following the Calling All Thresher/Permit Class SSN Fans thread you know that I want to build a model for a friend of mine, Travis Coley, who served on USS Greenling (SSN-614) from 1970-1973. In the process of deciding what to build I found an 11�x17� print of all of the Thresher/Permit class submarines and considered replicating it in 3D. While still considering my options however, I acquired a good set of plans for Permit and decided to see if I could use them to scratch build Greenling. In case you didn�t know, there were 14 subs in the Thresher/Permit class with various configurations. Greenling was both longer than Permit, and had a larger sail, so significant modifications had to be made to the Permit plans to convert them to Greenling.

The first thing I did was to import the plans I acquired into AutoCad and scale them. I then traced the circles associated with the different hull sections and copied them to the plan view at the appropriate places. The alignment was good, so I then traced the hull and sail on the plan view as well. To make Greenling, I then copied the whole mess and stretched the hull by simply moving the aft end back to 292.25', and adjusted the hull sections accordingly. I left the sail as it was. The next thing I did was bring the Thresher/Permit print shown above into AutoCad and scaled it. I then copied the outlines and sails that I had drawn, onto the corresponding subs on the print. You can see that the hull matches are pretty good. Thresher is a little off due to picture alignment, but the sail is the right size and in the right location. The outline for Greenling is spot on, so assuming that since they got the sail right on Thresher that they got it right on Greenling too, I traced the print sail and transferred it to the plan sheet. I then, as it has turned out, wasted time making a spine and ribs for the hull sections. To this point, I was really having fun, and things were about to get even more exciting�

UPDATE 2
With the preliminary hull design completed, I turned my attention back to the sail. The only dimension I have found other than on the plans is the height, which was 13.5� on Thresher/Permit, and 16� on Greenling. I also learned that the width was increased, but I don�t know by how much. I assumed the increase was more akin to the height increase than the length increase. Using the sail dimensions obtained from the print, I copied and scaled a picture Tom Dougherty sent me of Gato (SSN-615), that had the same hull and sail configuration as Greenling, and overlaid the traced sail. The alignment of the sail was great, so I used it to determine the sail plane dimensions and location. For comparison between the two sails I also overlaid Permit�s sail (in yellow). Now comes the really fun part�

A friend of mine has access to a stereolithography (SLA) system and said that he could use it to make the small parts for me. If you aren�t familiar with it, the SLA method uses an ultraviolet laser that solidifies a thin liquid photopolymer resin. After one layer is solidified the SLA elevator platform is lowered 0.05 mm - 0.015 mm (0.002� � 0.006�) and the process is repeated. This continues until the whole part is completed. The advantage of this is that the parts can be generated straight from 3D AutoCad drawings, which I have recently learned to do.

So, my first session in virtual modeling began, as I took the 2D plans I had generated and converted them to a solid 3D model, starting with the sail. The results were pretty encouraging, as you can see in the photos below. The last picture shows a comparison with Gato. You can also see where my �model� is hollow as I designed it to be 1/8� thick, upon advice from my friend. So, I�m having a blast so far, and it is about to get even better still.

UPDATE 3

When I got to this point my friend came in from out of state to visit his father. When we got together I showed him what I had done, and he told me that he could probably do the whole ship if I divided it into smaller pieces, and recommended that I construct the entire ship and then �slice� it to make parts small enough that he can fit in spare spaces as he makes parts he needs. He recommended that they be no larger than about 4�.

Travis told me that he would like a model about 2� long, so I had originally planned on doing the model in 1/150 scale. I was then advised that 1/144 scale is more standard and that I may be able to find accessories at this scale than I would at the 1/150 scale that I was originally planning to use, so I recreated the ship in her entirety to make a single model at 1/144 scale. At 1/144 scale the model will be 24.4� long versus 23.4� at 1/150 scale.

The �model� I made was a lot of fun to do. In the pictures below, parts in red are removable and will be SLA�ed separately. The blue is one solid piece that I will subdivide. The last picture shows the aft end �exploded� so the detail of the parts can be seen. The upper rudder is out of view.

Enjoy! At this point, it seems more like a virtual build than a model, but that makes it even better, since I�m really getting to build 2 models.

CHEERS!!!

UPDATE 4A

Oh Boy! Was it ever a lot of fun taking apart the �ship� that I had put together with one set of pieces to generate another set of pieces so that I can build another �ship�?! If you have been following the Calling All Thresher/Permit Class SSN Fans this will seem familiar to you as I posted essentially the same thing there yesterday before I decided to start this WIP on this site.

I started by segmenting the ship into seven segments, because my buddy said that he could do parts up to about 4� long. With seven segments the largest piece is 4.0� x 2.5� at 1/150 scale. AsI said in the last post, based on advice I was given that 1/144 is a more common scale, I�ve decided to build her in 1/144 as opposed to 1/150, so the largest piece will be 4.2� x 2.6�, which is a little long but 4� was an exact limit. There are 13 parts, with 3 of them being duplicates.

I should perhaps mention that my buddy said that the parts couldn�t be solid, that they had to be hollow. We agreed that 1/8� (0.125�) would be sufficient. Increasing in size to 1/144 increases this value to 0.13� when I scale the model as is, which I will do, because to do otherwise would mean essentially redoing it. Again though, this small increase in width shouldn�t be a problem.

Below are images of the parts, beginning with an exploded view of the model with the individual parts identified, followed by close-ups of the individual part so the detail of each part may be seen. Having put her together, I had to �paint� her, so the last few images show her �painted� in the proper colors. Due to the 10 pic limit on this site, the images will be split onto two posts.

All of the design was done using AutoCAD Civil3D. The �Realistic Visual Display� option (using default settings) was used in all of the images.

After segmenting the ship and hollowing it out I decided to provide a means to align and provide support to the pieces. I did this by adding a �� wide strip at the ends of each piece, in which I �drilled� 3/8� holes through the center of to accommodate a 3/8� rod down the middle of the hull, which may not be necessary. I also �drilled� small holes on the aft side strips and put slightly smaller extrusions on the forward side strips for aligning the parts readily. I put two on each side, but probably could get away with one, and in act have already changed it although the pictures don�t reflect this change.

Because of size restrictions, the sail had to be a separate part, so I cut it out and extruded some small knobs, which fit into holes drilled in a plate I attached inside the hull. The knobs probably aren�t necessary, but they look cool and I�m going to keep them.

The tail section and to a lesser degree the diving planes took the most time to complete due mostly to me not taking the right approach to doing it. An interesting thing about creating parts in AutoCad is that there is usually more than one way to make a part, and some are better than others. In hindsight, there was a far easier way than the way I did it, but such is life.

I put the �painted� model over a light blue background and I think it looks pretty cool. I�m sure if I knew how, I could change the defaults to make it look better, but the intent here was not to build a virtual model, but to create the parts for a real model.

ENJOY! The remaining images will follow shortly�

UPDATE 4B

And here are the rest of the images. First the remaining parts� And now the "painted" ship. CHEERS!!!

I was at General Dynamics Quincy when the "14 boat" was commissioned. Nice to be reintroduced to her.

visitor wrote:I was at General Dynamics Quincy when the "14 boat" was commissioned. Nice to be reintroduced to her.

How cool is that?!

UPDATE 5
I�ve been wondering for a while what I was going to do about the screw, and then I found this picture on the Net. The same article that had this picture also reported the diameter to be 15�, which at 1/144 scale is 1.25�. After looking at the picture for a while I figured out the geometry. The tailing edge is a curve on the plane of the aft end of the screw. The foreward edge of each blade is off set at a constant angle from the tailing edge. The aft and forward points on the hub and the end of the flat arc on the tailing edge define a plane that the other curved line is on. I decided to try building it in AutoCad. The one remaining question was, how thick, or wide was the screw. Once again the plans came in handy, and although there is no detail of the screw on them, the plan view clearly shows how wide it is. Using this dimension I was able to recreate the screw remarkably well. And it looks pretty good on the �painted� ship too! I�m pretty darn happy with the way it turned out. It was definitely the most complex part I�ve ever done. It�s got me wondering if I can use the part we make to make a low temperature metal cast. It would be cool to have a metal screw.
I sent my buddy a test file to make sure he could open them and he can, so the next stage is to try a part or two and see how they come out. I�ll keep you posted.

UPDATE 6
Based on a comment I received on the Subcommittee site, I redid the screw. Although I don�t think it�s perfect, it�s better than it was and I like the way it looks.

CHEERS!!!

To be honest, I have no big knowledge about submarines Russel, but it looks really proffessional until now. Looking further here for progress!

Thanks Christian,

Long time no hear! I hope all is going well.
I have no big knowledge about submarines either. But I'm learning!

UPDATE 7A
There has been both progress and modifications made in the Greenling dry dock. First, the first 2 parts were manufactured on the SLA on Tuesday and completed Wednesday. We decided to start with Parts 6 and 7, because Part 6 is the most intricate part and Part 7 matches with it. This will allow us to test both the detail provided and the fit between the parts. My buddy took a video of it on his i-phone while they were being made and sent it to me. I did a screen capture of it while one of the pieces was being zapped by the UV to solidify the liquid resin. The blue glow on the right side is the part being zapped. Unfortunately, my buddy had to go out of town, and won�t be back until Friday, so I have to wait until then for pictures and for him to mail them to me. Even if the test pieces prove to be perfecto, they will need to be redone, for two reasons. First, the details have not been applied to the surface yet, so we knew before the test that they would have to be remade. Second, I changed the design.

When I did the original design I was thinking that I needed to have a spine down the middle of the hull to strengthen it, so I incorporated plates on the ends of the pieces to accommodate the rod I was planning to use for the spine. I put tabs on the plates for radial alignment. After further thought, I decided that the spine wasn�t necessary. My buddy not knowing the thought process behind the design asked me why I designed it the way I did and offered a better way to connect them. Because it is a better design, since the spine is not needed, I redesigned the model to incorporate my buddy�s recommendations.

For those of you with AutoCad experience, here�s a little tip. When making the hull pieces in the initial design, I made two pieces, one smaller than the other, and used the �Subtract� command to make the pieces. In the new design, I used the �Shell� command, which my buddy says is a much cleaner way to do it.

On the new design, I eliminated the plate and modified the rims of the hull pieces so that they slip inside of each other like you see in some pipes, with one end being �male� and the other being �female�. To align the pieces radially I incorporated keyways. The male and female parts of the keys are the same size, so I don't know if they will mate or not. I may need to make the males slightly smaller, say 95%? I won�t know the answer to this question until we perform our next test.

I also changed the way the sail attaches to the hull. When I redid the sail I made it taller than it needed to be, so I could more easily attach it to the hull. When I was making the hull part that mates to it, I put it in place and subtracted it. When I then moved it and saw the nice cavity it created in the hull, I just decided to mate the parts by simply sliding the sail into the cavity. Again though, they are the same size, so I don't know if they will mate or not.

The new plans are shown below, and on a subsequent post, due to the 10 pic limit on the Forum. The Parts Diagram and Parts 1 � 5 are shown below, Parts 6 � 11 are shown on the next post.

Enjoy! And�

UPDATE 7B
Here are the remaining parts. So, to this point, things are going well and I am having a blast doing it. Like I have said before, It�s like playing a computer game and scratch building a model at the same time.

On another note, it has been suggested that when I finish I could use the parts to make resin molds for making multiple parts and selling them as kits. Is there any interest out there? Would anyone like to have a 1/144 scale resin model kit of USS Greenling (SS-614)? If so, let me know.

CHEERS!!!

UPDATE 8

GREAT NEWS! My buddy sent pictures of the completed parts today and they came out great. I don�t know what I was expecting, but I wasn�t expecting the plastic to be opaque. It gives a weird effect, but I think it looks cool. The opaque nature of the parts makes it difficult to see what the gap is like from the pictures. I will have to wait until I get them in the mail to see how pronounced it is, but from what you can see it doesn�t look bad. The holes and plugs of the original design came out nicely. I made the pins 90% the diameter of the holes thinking that they would then fit snugly without sanding. The tail (stern) section came out extremely well. I don�t know why, but it amazes me how much it looks like the AutoCad model. The parts are together because for some reason the guy that actually made the parts put them together and my friend said that he is afraid to try to take them apart because he doesn�t know if it was glued or not. At least we know they mate well, because I suspect that he did not use glue and it is simply a tight fit.

I guess now it is time to start detailing her. I think I�ll start with the Mushroom Anchor. Any and all advice is most welcome!

CHEERS!!!

Absolutely brilliant work Rdutnell!!!

Thanks for sharing each step and the thought process you went through as well!

It really looks incredible! As for a model, I could potentially have interest but I fear that in resin the price tag would be unbearable for me (beware also of some re-engineering given that a 2 feet resin tube would be very heavy and could "break" at the joints...). Also I like 1/350 better, but that is just me.

In any case, now that you have started, you are only limited by your imagination: 1/144 scale is definately a scale with potential for many other boats to be made!!!

Bravo!


Nicola

Hey Thanks Nicola! For the nice words and the advice. You aren't the first one that has warned me about the amount of resin needed, and therefore the high cost. And I think you are right, a redesign would be required if I end up trying to make multiple copies, although I know pretty much nothing about resin casting. Anyway, it may not matter, becuase there hasn't been much interest in it yet.

CHEERS!!!

UPDATE 9
Hey All!

The first step in detailing went well. The Mushroom Anchor is added and it was a snap. With the aid of the plans, I simply drew a sphere of the correct size and put it in the right location. In the attached images, the Mushroom Anchor is green, the rudders are cyan, the diving planes are yellow, the screw is orange, the screw shaft is red, and the hull is a shade of blue. The next things I am going to try to add are the so called Zincs (see below), whatever the heck they are. Using the plans once again, I was able to locate the Zincs (Magenta in the image below), but I haven�t seen a picture of them yet, so I don�t know if they are supposed to be recessed (I assume) or raised from the surface. Does anybody know what they are for and/or what they look like? Pictures would me mucho appreciated!

Does anybody know what they are for ...

well, zincs are exactly that: zinc anodes. They are used on areas of metals to provide a substitute surface for corrosion to occur on. I'm not sure I know why they would be stuck on that part of the side of a sub though, but it makes sense. They would just be a solid bar of zinc with holes in it so it can bolted onto the hull.

See:
http://en.wikipedia.org/wiki/Anode
particularly the section 'Sacrificial anode'

http://www.navsource.org/archives/08/08594a.htm

for pictures of the USS Permit. (2nd boat of the USS Greenling's class)

Several good stern shots from during her construction. I am not able to see any recessed troughs for zincs in the pictures.

http://navsource.org/archives/08/591/0859434.jpg
http://navsource.org/archives/08/591/0859436.jpg

UPDATE 10
Good Morning All!

And thanks for the feedback codythecat!

With the feedback I received both here and on the Subcommittee forum I made some adjustments to the Mushroom Anchor and did the zincs. For the mushroom anchor I used a larger diameter sphere and moved it in more. I then subtracted a smaller sphere from it to create the �dimple�. For the zincs I made a single 0.01� thick bar, with a width of 0.0564�. This is wider than 0.0417�, which would be 6� in real scale (as per some plans I was provided), but it agrees well with the Permit plans. Every 0.0833�, I cut 0.002� wide, 0.002� deep notches in the top and sides to delineate the individual slabs. I then mirrored this around to all four sides and sliced the one by the mushroom anchor. These should perhaps be wider, but I may be taking these off again anyway. More on that later.

I also �scribed� the �Access to Free Flood Area�. I did this by removing a 0.01� wide and 0.01� wedge around the perimeter of the feature drawn and located according to the plans. Most recently, I �installed� the MBT No. 7 valve. Or rather I carved out a spot for it, because I don�t want it to be plastic. I may have access to a PE system, in which case I will make them out of PE. If not, I sized the cavity with a 1/8�OD and 1/16�ID. That makes it a hair smaller than on the plans, but if PE isn�t an option, I think it would be beneficial to have them a standard size. If PE is an option, then I can always change it if I want. In any case, I left it red and yellow until I make a final decision on it. A little bit on how I am sizing and locating the various features�
AutoCad is wonderful, because it allows you to put scaled pictures on any plane. Then you can move it or rotate it just like any other object. Plus, the back side really is the back side, i.e., a mirror image of the front side. So, After importing and scaling the plans I align the tips of the screws. This puts the plans square in the center of the hull. Change your viewpoint and you are looking at a top view. The image above is in �Realistic Visual Style.� If you change it to �3D Wireframe Visual Style� you can see items below the part. If you want to look at a different view, say the starboard side, you just move the plan to the appropriate screw end and rotate it as needed. To see below the part, simply change the visual style and tada� You discover that you messed up. While preparing this little description, I noticed that somehow I got the diving planes too small. Oh well, back to the drawing board. Anyway aligning and moving around in this way allows you to get proper location of an item in all 3 planes.

As always all comments are welcome!

CHEERS!!!