Basic Information
The fleet oiler is a form of Fleet Auxiliary (that is, a naval vessel that is not a warship) which provides direct logistical support to a battle fleet. As the name implies, a primary function of an oiler is to carry fuel - before the days of oil fired propulsion, a collier would have substituted, but in that era refuelling underway was not really practicable. As implied, this also means that an oiler carries the necessary equipment for underway replenishment. Besides fuel, an oiler may carry general stores, food, fresh water, spare parts and even ammunition, but fuel is usually predominate. To serve in her role, the oiler must be capable of keeping up with the cruising speed of the fleet - which tends to move a lot faster than normal merchant traffic and requires specific purpose in design or extensive modification. Armament is generally minimal - under normal circumstances she relies on being deep within the fleet's defensive screen and then dropping back if that may be compromised by a full scale engagement. Any weapons systems that do exist are liable to be concentrated on air defence.
When not accompanying the fleet, an oiler is generally found rushing away from it towards a supply depot or moving to rendezvous with it at sea - this is usually when they are most vulnerable (or at least on a par with when they may be caught straggling behind an engaging fleet) - and when careful analysis of their movements can help determine where the actual fighting fleet has got to.
The ability to deploy oilers and similar ships is an often overlooked aspect of naval power - their numbers and efficiency place a hard limit on the ability of the fleet to operate at a distance from its home ports, but a limit that is often overlooked by more bloody-minded naval strategists.
Sources
Game and Story Use
- The Pacific Theatre of WW2 hinged severely on the presence (or, in most cases, the absence) of sufficient fleet oilers - in several cases opportunities were lost, or advantages in numbers could not be pressed due to a lack of fuel at hand, resulting in turn from a shortage of oilers (compounded in the Japanese case by not having much fuel to begin with).
- An interesting dilemma for a submarine skipper if he comes upon a oiler in transit: does he try for a high-value kill now, or attempt the far from certain task of following it to the rendezvous and locating the enemy fleet (usually a piece of intelligence not to be sneezed at).
- Not attempted in our time line, but considered, was the idea of nuclear oilers - that is, nuclear powered fleet oilers, designed to accompany nuclear powered carrier task groups and provide fuel for accompanying escort vessels too small to carry their own reactors. In our time line, common sense noted that you still needed to refill the oiler at some point and didn't save much by not refuelling it at the same time - a few more conventional oilers were a lot cheaper than the nuclear powered ships that were needed to substitute for … but in a more atompunk setting, who knows?
- Easily recycled in space - presumably carrying whatever passes for fuel (or possibly just reaction mass?), but maybe also atmosphere support and crew tender services where the sci-fi is hard enough.