These vessels were armed with fore and aft plasma cannons and possessed primitive shields. Although their weapons were considered formidable to a Y-class freighter, Nausicaan ships were outmatched by NX-class starships, whose spatial torpedoes were capable of piercing Nausicaan shields.
Three of these vessels, operating out of a Nausicaan cargo station, attacked the ECS Fortunate and raided its cargo for a period of several months during 2151. Fortunately, the Starfleet vessel Enterprise NX-01 was able to offer assistance during that year. (ENT: "Fortunate Son")
In the script of "Fortunate Son", this type of vessel was described as "small" and "fast." The bridge of a Nausicaan ship was scripted to be "dark," although the final version of the room clearly features large, colorful wall panels. Also, the offensive and defensive specifications of a Nausicaan ship were scripted thus; "Medium yield plasma cannons. Simple (TECH) shielding," where the word "tech" was later to be replaced by a more technical term. In the episode's final version, this became, "Fore and aft plasma cannons," and a less direct reference, immediately thereafter, to the craft having shields.
Star Trek: Enterprise's production design team received the instruction to design the studio model for the small Nausicaan attack fighter during the show's first season. Even though Nausicaan starships had never before been portrayed, inspiration for the forthcoming design was taken from how Nausicaans themselves had been established as typically behaving; due to their thuggish nature as belligerent troublemakers, their vessels had to have a fittingly threatening and aggressive appearance.
Illustrator John Eaves began designing the Nausicaan vessel by sketching out a variety of basic shapes. "I just threw a whole bunch of stuff together," he stated. These initial sketches included a design concept for a Vulcan ship, which Eaves had drawn earlier. The same ship layout, with blade-like curves, gave Eaves a design direction, which he expanded upon in the other sketches. As he became increasingly more inspired, Eaves felt the look he was aiming for was somewhere "between the bottom of a shovel and a manta ray." The producers approved one of the initial illustrations as the final version, a configuration Eaves likened to a manta ray. "On this one," he continued, "they chose a ship right off the first pass [....] It was a busy show, so I didn't get to flesh it out a little bit more, but I didn't need to."
The reason it wasn't essential for John Eaves to plan all the details of the Nausicaan craft was that the CGI artists knew how to proceed from his rudimentary design, anyway. At Eden FX, Lead CG Artist Pierre Drolet took Eaves' illustration and digitally turned it into a three-dimensional model. Drolet incorporated some of his own ideas into the design, shading the Nausicaan ship with an earthy color scheme, and added detailing such as the forward plasma cannons. All these finishing touches helped give the ship its highly sought-after aggressive look. (Star Trek: The Official Starships Collection, issue 30, pp. 16-17)
The bridge of the Nausicaan ship was built as a backdrop set on Paramount Stage 8. (Call sheet)
Presumably, these vessels had warp drive and could travel faster than warp 1.8, the maximum speed of the Fortunate, for them to be able to constantly locate, track, attack, and raid said vessel over an extended period of time. Issue 30 of Star Trek: The Official Starships Collection lists the Nausicaan fighters as having a maximum speed of warp two and a length of ninety meters.