The Permit-class submarine (known as the Thresher class until the lead boat USS Thresher was lost) was a class of nuclear-powered fast attack submarines in service with the United States Navy from the early 1960s until 1996. They were a significant improvement on the Skipjack class, with greatly improved sonar, diving depth, and silencing. They were the forerunners of all subsequent US Navy SSN designs. They served from the 1960s through to the early 1990s. They were followed by the Sturgeon and Los Angeles classes.
 
These 3D files are another superb offering drafted by Randy and offered here through the Nautilus Drydocks. Parts fit easily in most 3D printer beds that have a minimum z axis height capability of at least 170mm. 

PLA plastics are a viable filament to use, however we recommend PETG, ASA or ABS due to the fact that PLA has such a low melting temperature and is highly prone to warping in hot sunlight or a warm vehicle. 
 
As scaled, the boat dimensions are: 
 
Length: 1150mm (45")
Beam: 148mm (5.8")
 
The hull will accommodate cylinders of up to 4.25" diameter. The Nautilus Drydocks recommends our new 300 series SubDriver with the optional 3.75" diameter ballast tank.