from Ship Recognition Manual - The Federation, 2nd Edition, FASA

Notes - circa 2287:

     "The Great Awakening" was responsible for the addition of many ships to Star Fleet, not the least of which was the Nelson Class scout. This vessel shares many design features with the Constitution Class cruisers and the Larson Class destroyers, though it is not intended to act as a warship. The primary mission of the Nelson is to explore and map uncharted areas of space, to observe new civilizations and cultures, and, in some cases, to make initial contact. This has made the Nelson Class scout responsible for more contacts with alien cultures than any other vessel class in Star Fleet.
     When introduced on Stardate 1/8804, the Nelson was the most modern vessel in the Galaxy Exploration Command; it would prove to be one of the finest ships of its day. It mounted the powerful FWC-1 warp engine and was capable of cruising at Warp 8 for up to two years at a time. The Mk I was not particulalry maneuverable and relied on its emergency speed of Warp 9.9 to carry it to safety if it were attacked. Because of its mission, the Mk I mounted two forward-firing only, medium-power lasers, and the FSG shield generator, a single transducer system.
     When phaser weapons were brought into the inventory, the Mk Is were refitted as they returned from their missions. At this same time, the impulse engines were replaced with the FIC-3 system, increasing the power output by 10%. Experiences during the Four Years War dictated an upgrade to the FSF shield generator, its binary transducer giving the same protection at half the power expenditure. By Stardate 2/0006 all Mk Is had been refit to Mk IIs.
     On Stardate 2/0801 Star Fleet passed down the order to refit the Mk II vessels to the Mk III by installing FWC-2 warp engines, FH-7 phasers, and FSH shield generators. The change in the main engines would increase the overall power output by 30% and the maneuverability by 50% at the expense of the cruising and emergency speeds. FSH shield generators were installed for more protection, and, as an added defensive element, FH-7 phasers replaced the FH-2s. On Stardate 2/0806 the first of the refit Nelsons, the USS Sager, was put into service. In all, 114 of the Mk Ills would be commissioned before the introduction of the Mk V.
     The Mk IV mounted the FIE-2 impulse drive system. Only two of this model, the USS Moisanen and USS Manzer, ever entered service. Prior to their completion, the Mk IV design was changed and all other vessels under construction were altered to conform to this change. The Moisanen and Manzer were refit to the Mk V model within two years after their entry into service.
     The Mk VII mounted the FH-8 phaser system and the FSN shield generators. A major change in the arrangement of the weapons was incorporated in the Mk VII. The earlier models mounted two phasers with separate fire control systems, which meant that both could be fired independently but they required more space and operating personnel. In the Mk V, the phasers were put into a bank and a single phaser was added to cover the aft quadrant. The FH-8s, being more sophisticated and having a longer range, required the M-2 computer system. The FSN shield generators increased the shielding protection by 20%.
     Of the 273 Nelsons built, 88 Mk Vs remain in active service, with 14 Mk IIs, 12 Mk Ills, and 8 Mk Vs in reserve fleets. One Mk V is used by Star Fleet Training Command, and 32 Mk Is, 11 Mk IIs, 8 Mk Ills, and 3 Mk Vs have been destroyed. Four Mk Is were captured by the Klingons during the Four Years War; 16 Mk Is, 6 Mk IIs, 2 Mk Ills, and 1 Mk V have been listed as missing; 8 Mk Is, 10 Mk IIs, 22 Mk Ills, and 9 Mk Vs have been scrapped; and 4 Mk Is, 4 Mk IIs, 8 Mk Ills, and 2 Mk Vs have been sold to civilian commercial concerns.