Large vehicles, major repairs, and tool kits
 

Both GURPS High-Tech and GURPS Ultra-Tech include the rule that Armoury (Vehicle Armor) and Mechanic (Vehicle Type) tool kits can only perform major repairs on vehicles up to 10 tons. This suggests to me that a large, disabled vehicle (0 HP or less) cannot be fixed with a tool kit, and that major repairs are only possible with a no-equipment modifier (-10) or, if the GM is generous and the player resourceful, an improvised-equipment modifier (-5).

That is, of course, unless the vehicle is carrying extra-large tool kits. For a GURPS Tales of the Solar Patrol Patrol Ship, weighing 10,000 tons, a Mechanic (High-Performance Spacecraft) Portable Tool Kit (which counts as basic equipment) would cost $600 × (10,000 / 10) = $600,000 and weigh 20 lbs. × (10,000 / 10) = 20,000 lbs. (Heh. "Portable.") That would take up 10 tons of the 200 tons of Load the ship can handle.

Such oversized tool kits are really meant more like dedicated workshop facilities than on-board normal ships, right? I get the impression that, not counting ships that carry around their own giant-sized repair facilities, the normal thing to do is carry around a normal-sized tool kit, do only minor repairs, and if the ship is disabled, try to get it to a repair facility for major repairs. Or do you expect that most large ships would dedicated all that tonnage to major repair facilities?

Have I got all this right?

Re: Large vehicles, major repairs, and tool kits
 

Depending on the time period and ship mission, a historical ship might carry substantial self-repair facilities or it might not. But even the substantial facilities are mostly damage control and maintenance instead of real repair. So you understanding seems to be historically accurate.

I'm mostly basing this on WWI and WWII naval ships, which could possibly self-repair a substantial hole in the hull or some damage to the superstructure. But if a major gun turret was heavily damaged, or part of the hull was destroyed, then the ship had to return to a base for repairs. It was possible to make major repairs, up to and including replacing the entire front hull, but it wasn't something done from the ship's repair tools.

Re: Large vehicles, major repairs, and tool kits
 

Thanks for the confirmation.

Oh, and since my example Patrol Ship costs $90M, even minor repairs are going to be at a -3 penalty. Maybe the entire engineering deck includes a Mechanic (High-Performance Spacecraft) Workshop, $15,000, 2,000 lbs? Its +2 quality bonus, would, at least, cancel out most of the minor repair roll penalty.

I don't think it makes sense for patrol boats, naval or space-bourne, to carry that much repair equipment. I suspect those who perform minor repairs simply have to have a very good Mechanic skill.

Re: Large vehicles, major repairs, and tool kits
 

Most of the time, the goal of a carried repair system is to have the ability to patch anything that's immediately hazardous, then be able to either call for help or limp to a repair facility, and this isn't particularly different between large vehicles and small vehicles, it's just that for the large vehicle you might need to move components that can't actually be moved with hand tools (e.g. if a car blows a tire, you can use a hand jack to raise it and replace that tire. If a tank throws a tread, you aren't using a hand jack).

Re: Large vehicles, major repairs, and tool kits
 

An Audie Murphy weighs 10K tons, so it's a pretty large ship and the text is specific that they are maintained and modified by their own engineers. I'd assume that the Mechanic's Workshop, as well as a couple of other workshops for other necessary specialties, are included in the 10K ton Loaded Weight. Load is the "weight... of occupants and cargo that the vehicle can carry" and doesn't cover essential equipment - for instance, a Murphy probably has 2-3 lifeboats but you wouldn't treat them as cargo. Do the same with the toolkits and I think some of your problems go away.

I've toured a bunch of naval vessels, from WWI battleships to WWII submarines. Even the relatively small WWII escort destroyers had pretty substantial machine shops and I wouldn't be surprised if they had a couple dozen tons of self-maintenance equipment. A TotSP patrol craft should be capable of being maintained by Solar Patrolman and they're not all mechanical geniuses. Give them the tools they need.

Re: Large vehicles, major repairs, and tool kits
 

In the absence of a dedicated Vehicles book, I would suggest using the rules from GURPS Spaceships - SS1 has the rules for the crew doing repairs and guidelines for the cost to have more serious ones (like replacing destroyed systems) done at a spaceport; I believe it is SS6 that has rules for designing spaceports or vessels that can serve as mobile spaceports, plus rules on how large of vessels one can service (and I think you can have a spaceport service vessels larger than itself, it just takes longer, so you could potentially have a system on a vessel that would serve the same purpose for repairing the vessel itself).

Re: Large vehicles, major repairs, and tool kits
 

I was avoiding invoking the repair rules in the Spaceships series, as they aren't directly compatible with the rules in the Basic Set and the Tech books. My angle isn't to find some way to do this — I could just make something up — but to understand the implications of the limitations of tool kits. I'm using ships from GURPS Tales of the Solar Patrol as good working examples, but I might just as easily have used the tramp steamer or star freighter from Campaigns. I just expect more expertise from the crews of patrol boats and cruisers than I do from those of tramp steamers and freighters.

Re: Large vehicles, major repairs, and tool kits
 

Ah, well, then, looking at the rules in HT, I think you could probably justify oversized versions of the Mini-Tool Kit and Portable Tool Kit, rather than needing to have a full Workshop (still oversized). It's a bit of a stretch, particularly if you're dealing with components that are too large to really work on with hand tools, but is probably fine for typical GURPS levels of resolution.

Re: Large vehicles, major repairs, and tool kits
 

Given that the limitation is based on weight rather than anything that particularly maps to complexity, I suspect the limitation on tool kits is just that the tools in the kit aren't sufficiently heavy duty to handle the components found on larger vehicles.

Note that nothing in the description of tool kits say they provide spare parts -- they just let you install the spare parts if you have them. Some level of spare parts is part of the workshop, anything more major will require storage or manufacturing facilities.

Re: Large vehicles, major repairs, and tool kits
 

I would assume that a (space)ship that's expected to go on long patrols, and which might get damaged a long way from help, would have at least sufficient tool kits that they'd count as a tool kit large enough to allow their use for repairs. More likely they'd have a large enough workshop. 200 pounds per 10 tons is one percent of mass, which doesn't seem excessive (and includes spare parts, according to UT p.82). I'd also assume that the tools or workshop is part of the ship's base design for a long-duration ship.

I would also assume that even with such a shop, repairs to major systems that take criticals hits or the like would require constant tinkering and wouldn't give full capability. Of course, B484-5 says that such a system requires parts (so a mere toolkit would be insufficient without a supply of parts), and if it's really broken ('dead') it's going to require a complete replacement anyway.

When it comes to taking penalties for repairing expensive things, remember that extra time can be taken to offset them. I'd also consider looking at the likely price of an individual system or piece of equipment if something specific has been broken, rather than treating it as repairing the ship as a whole, which may lower the cost of the thing being repaired enough to reduce the penalty somewhat (probably not for bigger systems). I'd also consider bonuses for having assistants - not just the task assistance rules, but for large jobs saying that if a system is worth $10 million, and you've got a repair team of a dozen (and the system is physically big enough that they can all reasonably work on it at the same time) that each person is really working on a ~$833 thousand job, so the penalty is only -2 rather than -3. The rules on B346 for large/long tasks would apply.