As the Cold War intensified during the 1950s, nuclear deterrence became a key element of global diplomacy. The United States and the Soviet Union were keeping
pace with each other in developing atomic weapons and had deployed large manned bomber forces capable of reaching each other’s homelands with either forward
basing or aerial refueling. Both superpowers were also quick to take advantage of captured German V-1 and V-2 technology from World War II to begin development
of both guided and ballistic missiles for tactical and strategic use. Submarines had proven their worth in being able to travel undetected for relatively great distances,
so it wasn’t a big leap to utilize them in some capacity to deploy missiles. The U.S. Navy converted two World War II fleet boats,
USS Carbonero (SS-337) and
USS Cusk (SS-348), to carry a U.S. variant of the German V-1 missile, known as the Loon, which was first launched at sea in February 1947. At this time, the
supersonic Grumman Rigel (SSM-N-6) and the subsonic Chance-Vought Regulus (SSM-N-8) were being developed. Each missile was intended to carry a 3,000
pound warhead for 500 nautical miles. The Regulus missile was successfully developed into the U.S. Navy’s first sea-going nuclear deterrent (the Rigel project was
abandoned in 1953) and was initially deployed on the heavy cruiser
USS Los Angeles (CA-135) in 1955.

USS Tunny (SS/SSG-282) was the first submarine to carry Regulus. Launched in 1942, she was a Gato class World War II fleet submarine. Tunny completed nine
war patrols and earned nine battle stars in the Pacific war before being decommissioned in December 1945. During the Korean War she was briefly recommissioned
but later decommissioned again. In 1953, she was brought out for conversion to a guided missile submarine (SSG). This consisted of deck-mounting a large,
pressurized, cylindrical hangar, some 15 feet in diameter, just abaft the sail, with a collapsible launch ramp extending aft. The hangar could accommodate two
Regulus I missiles in a rotating ring arrangement. The missiles could be prepped while the submarine was still submerged by entering the hangar through an access
trunk. However, the actual launching required the submarine to surface and for crew to manually move the missile onto the rails before it could be fired. The boat
could submerge to periscope depth to guide the missile to the radar horizon. The
Tunny’s conversion was completed very quickly and she fired her first Regulus at
sea in July 1953. For the next several years,
Tunny operated out of Point Mugu, California, primarily as a Regulus test platform.

In October 1955,
USS  Barbero, originally SS-317 and also a World War II fleet boat, was brought out of mothballs and received a similar conversion to become the
Navy’s second SSG.
Barbero joined the Atlantic Fleet and Tunny remained in the Pacific Fleet, now based out of Pearl Harbor. Tunny completed ten deterrent
patrols and successfully launched a total of 100 Regulus exercise missiles, the only submarine in history to accomplish such a feat. In May 1965, the Regulus missile
system was phased out, and
Tunny was redesignated SS-282. Before long, the missile hangar was converted into a troop berthing compartment, and in October
Tunny was re-designated a troop transport submarine (APSS). She served in other capacities until she was decommissioned on 28 June 1969.
3-D printing has been around for nearly three decades, but it was primarily used by engineers and designers to make rapid prototypes in the aerospace, automotive
and defense industries. This kind of work was done with very large and expensive printers. However, in the last several years, with advances in software and
printer hardware, 3-D printing has become more accessible. Affordable desktop printers have brought this exciting technology within reach of self-starting
entrepreneurs, schools and home tinkerers. With that shift, 3-D printed products for scale modeling have become a reality and in many ways has revolutionized the
business, with parts, accessories, conversion sets and even full models being produced using this method. Mulsanne's Corner  is one of those cottage businesses
that are using 3-D printing to offer exciting options for ship modelers and their
USS Tunny SSG-282 conversion set is a fine example.

This set is designed to be used with the AFV Club 1/350 scale
Gato class Submarine 1942 kit (SE73510). Out of the box, this kit builds into a very good model of
USS Tunny in her original fleet boat configuration, so it would make the ideal basis for this conversion. The centerpiece of this set is the one-piece deck section
with the missile hangar and launch rails. The other parts include a new sail/conning tower, a pair of Regulus missiles, various sonar domes and blisters and
periscopes and antennas. Based on the introduction to the set’s instructions, the 3-D printing process used creates a material that is a type of resin, so you will need
to use the adhesives that you would use for more common resin parts and kits. The parts are translucent and if you look closely you will see that the surfaces are
not completely smooth. These striations are a by-product of the printing process and will require sanding with fine grit (400 grit is recommended) paper and
followed by a spot-filling primer. Also, the parts will need thorough cleaning before painting.

The parts are detailed and well done. They are all attached to what is essentially one long sprue, but the conning tower broke off during shipping. The deck section
is a replacement for that section of the AFV kit part, so some surgery will be required. The part has good deck planking and limber holes along the sides. The
hangar door is posed open and the launch rails up, so if you wish to close the door or lower the rails into a stowed position you will have to do some cutting and
modifications to the parts. The Regulus missiles are nicely represented but if you want to stow one or both in the hangar you will need to cut the wings to fold
them. The eight pages of instructions for the conversion set are very thorough and well done. The first page discusses the 3-D printing process, the steps
recommended to clean the parts and how to prep them for painting. The subsequent pages walk through an actual conversion with clear photos and illustrations to
show the placement of the parts. The steps are explained, photos are annotated and metric measurements are provided when needed. No decals are provided for
the Regulus missiles, so you will have to get some from other decal sheets.
The USS Tunny SSG-282 Conversion set is an excellent example of a 3-D printed accessory. With this set you can transform a Gato class fleet boat into one of the
pioneering missile carrying submarines, which visually was quite an oddity. The conversion set requires the cutting and removal of parts, so I would recommend it
to someone with intermediate modelling skills. This set from Mulsannne's Corner is available via their Shapeways page (Tunny Conversion Order Page) which also
has a link to download the instruction sheets. My thanks to Mike Fuller of Mulsannne's Corner for the review sample.
Felix Bustelo