My grandfather designed the official patch of his original WW2 submarine, the USS Darter. The design must have been originally his, since he appears to have concept sketches that look nothing like the final version. I don't know what year these drawings are from, but they are probably after the war. He made the patch in the 1970's for the Submarine Veterans reunions. The design appears on Navy publications after 1945. During the war patrols and the frantic life aboard a sub, it's highly doubtful he would have had the time to neatly draw these designs.
The "darter" fish is a small, distinctly-patterned freshwater fish in the perch family, found mainly in streams in North America. The subspecies depicted in his design appears to be a rainbow darter. Ask Wikipedia for a visual. What's a darter fish?
Anyway, I think the reason the "Darter" was chosen for the vessel was because the darter is a very small, harmless-looking fish. Much how submarines are much smaller than other navy ships, but are capable of destroying the biggest enemy fleet ships with a few well-aimed torpedoes, which are also nicknamed "fish". Many diesel submarines from this period were named after different types of fish.
1. The earliest drawing I can find shows multiple darter fish swimming around a torpedo. The fish are also not quite anatomically accurate.
2. Then, the design evolved into this. The shape of this one suggests a shoulder patch emblem. This has the basic elements of the final design, in that the fish is throwing torpedo-shaped darts at a big target on the side of a Japanese ship, which also looks like the Japanese flag. He was just experimenting with logo shapes at this point, but the concept was solid.
3. Here we see the inked version of a more finished-looking design. The ship is bigger and the target smaller. Notice this is a flipped version of the final design at the bottom.
4. Colored pencil study of the square logo. We see he was trying to play around with color ideas for the border of a circular design.
5. Marker full color rendering of the square design. For whatever reason, he liked the flipped version of this design better, and thought the logo should be in a circle (perfect squares don't embroider well)
6. Finalized design in a circular shape. Everything looks better in a circle. Logo design 101.
7. And finally, the embroidered finished product. The final patch is quite large and measures at least six inches in diameter.
Using my own talents, I scanned and traced this final design in Adobe Illustrator and turned it into a logo as would be painted on the side of a ship. I combined elements of the Task force 'M' patch, showing the date of the battle of Leyte Gulf and the Darter's final war patrol in which it was lost.
Hughie was a highly skilled draftsman, I'm not sure if he took any classes in mechanical drawing but he must have. Keep in mind this was much harder when you had to do everything on paper with inks and pencils. Once he had a nice clearly inked drawing, he could photocopy it and mail it (via real postage) to an embroidery place and have them create the custom patch. The process took many weeks. They did have machine-stitched embroidery then without a doubt, since World War II saw an explosion in individual unit insignia and uniform patch designs. This was the first conflict in which every regiment and division, fleet or aircraft wing had a distinctive and colorful emblem.
Now you see where my graphic design skills came from.