Arnold Rimmer once took two skutters and went on a ramble through the Diesel Decks as part of a 'vacation'. The Diesel Decks were so so large, and filled with so much machinery, that Rimmer's hike took ten days, with Rimmer and the skutters sleeping under the machinery. Although, this also may have been because the anally-retentive Rimmer stopped off to take photographs of every cistern, pipe, gear and valve he came across, noting their manufacturer and model numbers.
After his hike in the Diesel Decks, Rimmer planned to show his slides of the vacation to Dave Lister, who was recovering from space mumps in the Science Room at the time. Rimmer took over a day to load his slides into a projector in the sleeping quarters, and when Kryten told Lister about it, Lister feared it might finish him off.
As the gang traveled to Justice World, Kryten was forced to endure Rimmer's slides in the ops room of Starbug, and was so bored by the banality of it, his intelligence circuits melted. ("Justice", Series IV)
- Since Red Dwarf was powered by the Front Ramscoop directing hydrogen from space into the main engines (a fusion reactor), the Diesel Decks were certainly not part of the main engines of the ship. It is unclear exactly what purpose the Diesel Decks served, since fossil fuels such as diesel had long since been made obsolete by the time Red Dwarf left Earth. The ship also has solar panels and battery back-ups. It is possible that diesel is still used as grease and lubricant, if not fuel, and thusly the area gained it's name from the smell.
- It is possible the Diesel Decks provide power for other areas of the ship except propulsion, or for mining activities, since Red Dwarf is a mining ship owned by the JMC, and has two small moons embedded in it's underbelly for the purposes of mining.