[johndallman]

Mechanic is the IQ/Average TL skill of finding and fixing problems with most kinds of machine. Specialisation is required, but the existing list of specialisations is a bit odd, because it avoids overlaps with fixing weapons (which is Armoury), some things that come under Professional skills and some uses of Machinist. The defaults are IQ-5, other Mechanic specialisations at -4 (subject to GM adjustment), Engineer for the same specialisation at -4, or Machinist-5; many Engineer specialisations have defaults to the corresponding Mechanic. Familiarity with the type of machine being dealt with and equipment modifiers can be very important. It looks as if there's a minor error in Basic: (Clockwork) is listed as a Mechanic specialisation under Engineer, but not under Mechanic.

Artificer talent boosts Mechanic; Flexibility helps with rolls in confined spaces, and High Manual Dexterity and Ham-Fisted affect DX-based rolls. Mechanic is often needed for characters with the Maintenance disadvantage and is, naturally, a repair skill in design/repair/use triads. The skill dates from GURPS 1e, where it was specifically a Vehicle skill and had the first beginnings of the concept of required specialisation built in; the current structure of specialisations dates from 4e.

Mechanic is common on skill templates for characters who deal with machines, often as an adjunct to vehicle-operation skills. Action also uses it for planting bombs in vehicles and otherwise making them into traps, and reviving shot-up vehicles. Fantasy adds (Muscle Engines), and Fantasy-Tech has too many new specialisations to list. High-Tech adds detail on tool kits, and Low-Tech adds (Optical Instruments), plus (Mill Equipment) in LTC3. Magic has a spell that's useful for Mechanic as well as Lockpicking. PU2, PU3 and PU7 all have examples for this skill and Powers, Enhanced Senses and Psionic Powers have abilities that can boost it. Powers: The Weird adds (Millwork), which is the same thing as (Mill Equipment) and (Musical Instruments). Reign of Steel: Will to Live is full of Mechanics, since it's the basic "medical" skill for robots. SEALs in Vietnam adds (Life-Support Equipment) and (Propellers), Space has (Battlesuit), which presumably ought to be Armoury (Battlesuit), and Spaceships (Life Support), (Mecha), (Mining) and (Refineries). Ultra-Tech has rules for toolkits for large vehicles, also known as shipyards. Underground Adventures adds (Conveyors), (Power Tools) and (Pumping Equipment).

Overall, GURPS supplements have expanded the Machine Type category of specialisation greatly, but the other three types of specialisation hardly at all. There are some definite oddities in the specialisation rules for vehicles. I've mostly been thinking about this for a TL6-7 WWII campaign, where, for example, (Heavy Wheeled) for trucks gives a default to (Automobile) at -4 by RAW, although the Driving specialisations mutually default at -2, and the underlying technologies are very similar. For aircraft, if we stick to TL6 piston-engine planes, (Light Aircraft) covers everything from a WWI wooden biplane to a Spitfire, P-51 or FW 190, and is -4 away from (Heavy Aircraft), although the smaller of those are far more like the P-51 than the P-51 is like a Sopwith Camel. You could bodge that by using Mechanic (Wooden Aircraft) and (Metal Aircraft) instead of (Light) and (Heavy) at TL6, or you could say that the Mechanic default penalty is the smaller of -4 and the operating skill default penalty. And you still have a problem if the light aircraft has the same engine as a multi-engine heavy aircraft.

Improving this seems like a good idea. Something that might make it fit together a bit better would be to have Vehicle Type specialisations exclude the power plant. That would mean a TL6-8 car mechanic would need at least two specialisations, (Automobile) and (Gasoline Engine), and would benefit from adding (Heavy Wheeled) and (Diesel Engine). It looks neater, but skill bloat usually does: has anyone got a better idea?