The so-called Crescent Cruiser Class was originally termed the "Jang-Jo Class" (after the famous suborg Fleet Commander), and designed in 1481 to meet the MyuvYin Pyschophager Threat. With the collapse of the MyuvYinahuman empire, most of the ships were retired or decommissioned, although a few were retained by the Federation Space Fleet, where they served a peace-keeping show-the-flag role at the Barnard Belt for several decades, and again at Lacaille 8760, and several other hot spots. Apart from some minor skirmishes, none ever saw serious combat, and the last Jang-Jo Class ship was decommissioned in 1625.
The design was rather eccentric. The nickname comes from the fact that the pairs of large slender forward curved radiator fins with fixed weapon points at the ends looked like two crescents, with the main body of the vessel in the middle.
The vessel was quite large: 670 meters long by 250 meters wide at the greatest diameter, with the long and only semi-retractable crescent fins extending out by another 500 meters each, and ahead in a graceful curve by another 300 meters. Dry mass was approximately 65,000 tonnes.
The ship had quite a lot of firepower for its size, and generated an enormous amount of heat from the twin amat reactors, hence the need for the extravagant cooling fins. In comparison with other vessels its stealth capacities were poor, but this was not considered important in fighting the MyuvYin ai.
Armor consisted of 12 meters of composites and nanoablatives, and the point defense systems were excellent, consisting of phased-array lasers combined with PD metal storm turrets. As was the case with all vessels of this type, extensive nanotech repair bots were used to maintain the integrity of the hull systems. Primary motive thrust was by advanced amat drive while all-aspect manoeuvre thrusters use both backup/navigation ion and primary/combat amat thrust systems.
Main armament consisted of 2 forward facing heavy mass drivers, 6 forward and two rear-facing medium mass drivers, 4 forward and two backward facing particle cannon, 4 heavy and 12 medium laser turrets, 4 missile racks each capable of launching up to 60 "Sprint" high acceleration subturing autonomous kill rockets at a time. 10 hull mounted and 4 fin-mounted Close-In-Weapons-Systems were used against drones and to back up the point defense and laser turrets. 2 mine layer racks (100 reloads each) completed the arsenal.
Image from Chris Schaeffer
Heavy Laser Cannon
While of little use in the astropolitics of the time, the type did appeal to weapons buffs, and the template was eventually declassified and became public domain when the last Jang-Jo Class ship, the FSP SF Victory was decommissioned. Atlantis Militech, which bought up all the templates, renamed them the Crescent Class, and attempted to legally monopolise ownership, but enthusiasts distributed pirate templates, and eventually Atlantis Militech went along with the inevitable.
Of course with the second singularity, and the emergence of the Transapient Empires, the Jang-Jo / Crescent Class became ridiculously obsolete. However, before the establishment of the nexus, and even after, in isolated systems, a military enthusiast or petty despot could nano-grow their own ship, and use it for joyrides or to bully and intimidate the populace. At least until some ISO came along, claimed the system, and - if Sephirotic, deposed the dictator and instituted a nanotopia for the grateful citizenry, or - if Ahuman, recycled or enslaved everyone.
To this day, the Crescent or Crescent Cruiser Class remains a popular ship among sapients who are weapons enthusiasts. The term Jang-Jo Class is usually used to refer to the original specifications, which are almost never found, as every unit in existence has been modified or customised to a greater or lesser degree. Most Sephirotic polities (apart from the NoCoZo libertarians) forbid the ownership of such destructive vessels in highly populated systems, or allow only the defanged version that is much despised by purists. Also the resource cost (in terms of raw materials needed) is prohibitive in crowded systems, except among the wealthy, where the disarmed (apart from the standard anti-meteor lasers etc) version is popular as a pleasure craft. Away from the major centers, fully armed versions of the Crescent Class can be found in the more isolated regions, where they serve various purposes, ranging from toys owned by hobbyist neosemperists who happen to have enough resources in the scarcely settled regions to nanoassemble one, to full-fledged military craft defending medium and high tech local polities. In these lower tech volumes, they are extremely effective against smaller ships of same tech level or lower, or against lower tech vessels. Many replace the advanced amat-drive with the lower tech and more manageable pion drive.