Re: [Spaceships 2] Maintenance on Cheap Ships
 

If 'background feature' means 'incredibly important, especially to the matter at hand', I suppose.

In particular reference to the drive classification side-issue, the distance-independent jump time is directly contradictory to paragraph 3 (out of 4) in Spaceships' definition of a hyper drive.
Only if you slice possibilities up in a very particular way and make some enormous assumptions. Plenty of settings have means of sensing into hyperspace, potentially making it less sneaky than a real-space approach that people aren't looking for.

Re: [Spaceships 2] Maintenance on Cheap Ships
 

Oh, I mean't "background" as in "world background" not as in "unimportant background." Many background features of technology can be very important, but they often times don't change the fundamental nature of the technology item.

Again, Spaceships (and GURPS Space, going all the way back to it's first edition) tries to draw a clear dividing line between Hyperdrives and Jump Drives, but really there isn't a clear line. Devices called Jump Drives and Hyperdrives have shown up in fiction all over the place, often times with any number of features which would have Space(ships) classifying them as the other type of drive, but the two drive types types really exist on the same spectrum of FTL drive descriptions, just with differing features attached to them. "Instant jump skip" is one of those features, but what if a hyperskip only takes a milisecond, is that a Jump Drive? What about a second? A Minute? Same thing with Jump Points, Spaceships tries to make them a feature of Jump drives, but they can be a Hyperdrive limitation as well. Or even (though probably unusual) a Warp Drive limitation - but I could imagine a Warp Drive that can only engage once it travels to a particular place where the fabric of space/time is weak for some reason. This is one of those places where the genericness of GURPS just kind of fails, because it simultaneously tries to stay generic but also tries to classify things in a much stricter way than sci-fi authors have done.

The distinguishing feature of Warp drive is that you aren't leaving the normal 3+1 dimensions of our universe. You aren't going into "hyperspace," or jumping from point A to point B, but are traveling through xyz+t. Now, yeah, I've no doubt that somewhere in the vast collection of fiction there are any number of descriptions of "hyperspace" which may breach the general description I gave, but that doesn't change my point that the general distinguishing feature is the "otherspace" vs "our space."

As for real-space detection - in space while nobody can hear you scream, but everybody can see you coming. The problem with real space is that despite all the... space... there's no place to hide. The best you can do is mask your approach behind a heavenly body, but that only works up until you have to move past that heavenly body into line-of-sight of any sensor platform. And there will be lots of sensor platforms, if only to keep an eye on all the space junk out there that might be dangerous.

Re: [Spaceships 2] Maintenance on Cheap Ships
 

It is certainly true that the GURPS Spaceships list of types of FTL drive is very far from comprehensive.

I don't agree much with your particular points about it, though.
This is true, yes. Although 'not leaving' potentially includes jump drives - they don't necessarily need an alternate space to pass through, they just definitely don't pass through the intervening regular space.

But the idea that that's more fundamental than whether travel is instant, or whether it has strong path or endpoint restrictions is kind of arbitrary.
Everybody can see you coming...if they look really hard in the right place. Yes, yes, it's basically impossible to hide even baseline thermal emissions, let alone rocket exhaust, from interested parties maintaining a good lookout at in-system distances. (If you're in a realistic setting, which is far from safe to assume when dealing with FTL technologies.) Over longer distances, keeping a good lookout starts to entail a sensor array area measurable in square astronomical units...

Detection of ships in hyperspace, if it's at all useful, is necessarily faster than FTL vessels and thus faster than light - which is not necessarily true for any means of detecting warp or sublight craft. Also, it's really easy to have a hyperspace signature be much more obvious than a ship in real space is - especially if, as I suggested, there's no expectation that you need to watch for ships entering your system without such a signature.

Of course, it's certainly also possible for hyperspace arrivals to offer no advance warning at all. FTL is probably the biggest forced wild-card in interstellar setting building.

Re: [Spaceships 2] Maintenance on Cheap Ships
 

Re: [Spaceships 2] Maintenance on Cheap Ships
 

Ships traveling via hyperspace might encounter each out, meaning fights are possible in hyperspace. Also if using Jump Gate networks Jump-based drives (As opposed to Hyperdrive-based ones) don't need a matching gate at the far end, in fact return may be possible without a Gate at the far end.