The Fisher-class Light Tug consists of a standard Class Two spacecraft hull adapted from the Lewis & Clarke-class clipper attached to a standard container pod docking clamp as used by the Ptolemy and Ragnok classes of Fleet Transport/Tug, though turbolift access to the pod is omitted for practical reasons.
This then allows the Fisher-class to mate with a single container pod, though her crew is unable to routinely access its contents.
In an early phase of the New Technology engineering and materials breakthrough of the late 2260s, which lead to modernisation in all aspects of the Star Fleet from 2270 onwards, Starfleet Engineering's Research and Development (R&D) department designed and trialled three separate prototype spacecraft. These vessels, each specially tailored for a different role, were the very antitheses of Starfleet's usual "Class One Starships" which excelled at performing any task asked of them. In contrast, these new prototype vessels were specialist ships, better and/or more resource-effective than a starship at performing a particular task but totally unsuited to performing any other. As such, new parlance was introduced and this type of ship became known as "Class Two Spacecraft".
The three vessels, launched in 2262, were specifically designed to fill the roles of a short-range convoy escort and spacelane patrol ship, a fast courier vessel, and a scientific investigation and research vessel. They were launched as the corvette U.S.S. Jester NX-600, the gunboat U.S.S. Orca NX-601, and the science vessel U.S.S. Oberth NX-602 respectively.
Several years of trials and testing went into the shakedown voyages of these new designs and they acquitted themselves well, though their designs went through several modifications as more efficent layouts were discovered, and the Orca's design was further spit into two separate mission roles. However it wasn't until the advent of the two-day Klingon-Federation War of 2267, also known as the Organian Conflict, that prompted intense interest in the programmes from the Federation Council and Starfleet top brass.
While the Federation's Class One Starships held their own against the modernised Klingon fleet, Starfleet's stable of older ship classes were gutted. Scores of older Kovaris-class destroyers and Baton Rouge- and Mann-class cruisers had been destroyed or wrecked, and the smaller border patrol and escort units had also suffered heavily. As a result, a crash construction program was authorised to replace the war losses and fill out Starfleet's support ranks with modern vessels. The production run lasted ten years and produced over 480 vessels from 2269 to 2279, able as they were to be produced at civilian-rated shipyards to commercial specifications rather than Starfleet's more stringent requirements for their starships.
Being so easy to construct by commercial and civilian yards, more and more designs were developed to take advantage of this hull-form and adapt it to many single-use roles outwith the original three envisaged.
By the mid-2270s both the classic Ptolemy and New Technology Ragnok classes of Fleet Transport/Tug were in service and these two-hundred-plus (there would eventually be two hundred & forty) ships were already being utilised at 100% capacity, and in many cases even more than that. So effective had the container pod & tug system of logistics been that over 80% of all Starfleet cargo was now being hauled in this manner and many official Federation government cargoes were also being transported by container pod.
Alternates for less urgent or smaller loads were still using Starfleet’s rapidly-aging Sherman and Independence-class freighters, or had to resort to the Federation Merchant fleet, corporately-run cyclic freightliner routes, or privately-held civilian charter freighters.
However, a new need soon emerged from Starfleet and the Federation government having put all its eggs in one basket. Because of the Fleet Tugs' typical route of hauling a three-pod train to off-load at multiple but widely-separated destinations, some cargo delivery was in fact being significantly delayed. It was found that many containers were being held until they were full before being released for transport to ensure maximum usage was being wrung out of a Fleet Tug’s delivery schedule, and this was unnecessarily delaying the loads that were ready to go.
Another logistical analysis was performed and it was determined that a second tier of smaller loads heading to local destinations would at a stroke provide a three-fold increase in efficiency. This second tier would simultaneously:
To this end, a new specification for a Light Container Pod Tug was drawn up.
The requirement itself was fairly simple. The proposed Light Tug must possess:
From these requirements it was obvious that the tractor unit would have to be smaller than the light cruiser-sized Fleet Tugs it was to compliment while still having the engine power to haul a pod with the mass of a Class I Destroyer and envelop it with its warp field. Several designs both new and reconfigured were put through computer simulations, and two would make it through to the final selection. One was the Starfleet favourite from the start, but the other would end up being widely accepted for the civilian market.
It was decided early on that the tug’s base power usage level should be as low as possible, thereby freeing up as much engine power for the actual propulsion of the ship and its load. As such, a permanent tractor beam linkage was discarded from consideration very early on. The tug should simply clamp on as did the Fleet Tugs.
Similarly, only basic computers, navigational equipment, and low-power crew recreational facilities were to be included so as to reduce the per-second power consumption index. This was balanced against crew productivity and health and the number of crew actually required for the envisioned role.
With its low speed, low flexibility, and low crewing requirements, it was inevitable that a Class Two solution would be provided. Taking up far fewer resources per hull yet still adhering to minimal Starfleet specifications, the internally reconfigurable New Technology Class Two mini-saucer section with its underslung pylons for additional payloads was an obvious choice, fitting in perfectly with the so-called “Modular Starfleet” of the 2270s. Further, utilising the Class Two main section allowed for an extremely simplified procurement chain and an immediate boost for appropriation authorisations and construction contracts. Basically, any yard already producing any of the new Class Two designs could simply add this design variation to their blueprint databanks and begin construction immediately.
All these things going for it and the resulting logistical benefits from pursuing it amounted to an Urgent Operational Requirement in its favour, and the Class Two Light Tug was green-lighted for development. The Class Two Lewis & Clarke-class clipper/high-speed courier/diplomatic cruiser was selected for modification of its basic design to that of the new Light Tug due to its existing passenger-transportation role. Within a week the re-design was completed and tested to satisfaction through computer simulation. Being suited in most cases to its intended new role, broadly speaking only two major internal changes were made:
The engineering aspect was tricker to manage, as – like the full-sized Fleet Tugs – the Class Two spacecraft's small SW27/1-4K warp drive nacelles had to be specially set up with a dual-operation mode. This was to allow the vessel's crew the ability to reconfigure the warp field envelope to cover both the 24,000 MT mass and 103-metre length of the Class Two tractor unit alone and the five times as heavy and over twice as long combination of vessel plus fully-loaded container pod.
As a direct result of this larger and more power-hungry warp field envelope, the Light Tug's maximum safe cruising speed while towing is limited to warp four, while the unburdened tractor unit itself can manange a warp seven cruising speed.
This new class was christened the Fisher class after ?
With its first-batch units constructed within six months, the Fisher class was an immediate success. Able to transport any single container pod to where it needed to go, it met the requirements perfectly and even exceeded them with a warp four cruise speed. In this way it became the modern successor to the venerable Independence and Sherman classes, more and more of which were phased out of service in the core of the Federation where container pod usage was at its highest. Those ships which remained in service were moved to frontier colonies which could not fill or utilise container pods effectively, or converted to robot ships for very low priority loads.
Members of the Fisher class soon became a very common sight orbiting the worlds of the Federation Core Sectors as their numbers grew to one hundred over a short span of years.
With a small crew of twenty or less, travel times of under a month, and greater in-port time as pods were still being loaded instead of being ready, as well as letting the dock workers and port authorities handle everything, Fisher-class Light Tugs became popular with Staff officers in training and sight-seeing low-ranked Starfleet crew at the start of their career or terms of service due to the opportunities they provided for shore leave on so many different planets of the Federation.
A single year gaining experience and seniority on a Light Tug run began to be seen as a good career move for cadets and junior officers just graduated from the Academy to round out or even begin their experiences of just the varied cultures within the Federation. The short tour of duty ensured that they could quickly be reassigned to a full-sized starship when they so chose, or pursue other opportunities.
Further, considered as “light duty” by Starfleet Medical, personnel recovering from injuries or sickness could be assigned to these vessels to continue their recuperation and re-integration back into Starfleet for full active duty. After the traumatic experiences of many Starfleet personnel from the Taal Tan Offensive by the Klingons in 2283, this became an oft-utilized option.
In the almost forty standard years since their introduction, the ships of the Fisher class have performed their limited role ably and flawlessly, and proven to be a true successor to the Independence and Sherman classes of almost a century ago. They continue to serve in the same manner and no end is yet seen for that service as they are perfectly suited to it. Upgrades to new-build ships and refits to existing vessels also ensures that the class remains up-to-speed with modern developments, and thus competitive within their niche but still vital role.