Cary L. Brown said:
"Weight" is not the issue here at all. Weight is simply the term we use to describe the force applied by a given mass under a given acceleration... the acceleration in question being that of gravity.
It is true, then, that the ship is "weightless" but that is irrelevant. It is not MASSLESS, and it is not acceleration-less, either.
I know all that. I'm pointing out the fact that the ship is not subject to a constant external accelerative force throughout the entire balance of its lifetime like naval vessels and aircraft. The lack of that force means the lack of weight; the lack of weight means the lack of long term stress on a particular load-bearing point. So if you break the keel of a starship, it's not going to collapse under its own weight, because no part of the ship has to support the weight of any OTHER part of the ship.
As far as this applies for longevity, it means that under rest conditions, or while flying at warp, no part of the ship is experiencing any significant mechanical stress. In those situations, the should would still hold together even if the entire space frame were made out of cardboard; no loads, no stress.
Cary L. Brown said:
In fact, the accelerations seen by these ships routinely exceed, by massive measures, that seen from gravity.
As I already pointed out, inertial dampening fields don't appear to work that way. Any device that could compensate for that much acceleration uniformly for every single object on the ship would actually BE a propulsive force acting on the entire ship. Besides the point I already made: if the CREW are not being thrown into the bulkhead at fifteen thousand gravities, then neither is spaceframe. And artificial gravity doesn't appear to be a structural problem either, since each deck has its own grav plating; it would appear the gravitational fields truncate at the ceiling above them, so the only load-bearing structures on the ship have to support the weight of anything that is directly above them, and nothing else.
Cary L. Brown said:
the question of "structural integrity forcefields" and "inertial dampening forcefields" doesn't necessarily negate that... in fact, I'd think it would be quite the opposite. The IDF, as presented, is a forcefield that creates an opposing acceleration on the interior of the habitable areas of the ship, in order to avoid turning the crew into strawberry jam against the bulkheads when the ship makes even just "routine" maneuevers (much less extreme ones!). But remember... "for ever action, there is an equal and opposite reaction." So, it seems to me that in order for an IDF to work, you'd really need to have your hull be TWICE as strong...
Think about the physics involved here, Cary. Even assuming the IDF only works INSIDE the ship, then you've got a system that is applying tens of thousands of gees of acceleration to everything inside the ship at any given time; say the interior, affected by the IDF, has a mass of X.
X is being accelerated forward at, say, 15,000m/s^2. Even if the EXTERIOR of the ship (hull plating, engines, some weapons) weighs half of X, all that kinetic energy still transfers. Action, reaction. So the same acceleration the IDF gives to the interior is ALSO given to the exterior in the opposite direction. In short, you end up with two propulsive forces working against each other; the ship either peels itself like a banana, or the acceleration from the engines and the acceleration from the IDF fields cancel each other out.
The much more likely scenario is that IDF fields are simply a functionality of artificial gravity; you can very the intensity of the gravity field in certain areas of the deck to pull the crew and some of the furniture in one direction or another to counteract some sudden movement, like something crashing into the ship at hundreds of miles per hour. Of course, on at least one plane, the pendulum effect comes into play; every time the IDF fields move the furniture, the furniture moves the ship (as Riker apparently understood when he shut off the inertial dampeners in "The Chase" to make it look like Enterprise had lost attitude control).
Cary L. Brown said:
Clearly, this is what was in mind when they came up with the whole concept of the SIF. There was simply no way that a ship would be able to handle those massive accelerations except by, for all practical purposes, having the "framework" of the ship be as much energy as it is matter.
I don't think so. As far as I can tell, SIF fields only come into play when some part of the ship's internal structure has actually been compromised and preventing the risk of nasty things like explosive decompression, tractor beams, shock damage from weapons or objects hitting the ship. Being integrated into the spaceframe makes plenty of sense; in the same way IDF is a shock absorber for the crew, SIF would be a shock observer for the ship.
Cary L. Brown said:
Go to impulse fast enough to accelerate out of the solar system in a matter of hours rather than years, and you're putting a MASSIVE amount of acceleration, and thus mechanical stress, on the system.
I don't think we're looking at that much acceleration AT ALL, considering the presence of subspace fields throws the entire balance of forces completely out of whack. At the very least we've seen a space station use those subspace fields to lower its effective inertia enough that a handful of thrusters could push it across the solar system in a single day. Starships--which do this by DESIGN--would find the same feat much easier to do. And this is equally true of space craft that aren't even warp capable; it would seem the ability to create a subspace field by some means or another is as fundamental to space flight as wings are to aircraft, and probably not at all difficult to do.
Either way, we have what we see. For some reason, nothing inside the ship is subjected to the massive accelerative forces you describe here. This leads us to one of two conclusions: either those forces are present but do not affect the ship's interior (above, I tried to show this is implausible) or those forces are NOT actually present, because starships are not using pure acceleration to attain high speed. Given the tendency of starships to inexplicably "stop" in deep space, I think the latter explanation is a bit more likely.
Cary L. Brown said:
But we DO have (1) basic physics, (2) "treknology" as it has been established, and (3) anecdotal evidence of how long ships typically last "in-fiction." None of those support the idea that ships would last for any more than a few decades in the Trek universe.
Well, we do have the Stargazer which, judging by the configuration of its bridge, could easily have been seventy years old by the time it was abandoned; seemingly, built around the TWOK-TSFS years. It's a question of whether or not the ship would still be in service if it hadn't been wrecked at the Battle of Maxia; an even bigger question is what Starfleet did with it AFTER the Ferengi gave it back to them. Part of me thinks they refurbished it and put it back in service, but that's just bias because I think it's a really cool ship.
Cary L. Brown said:Oh... and welcome back. Nice to see ya...
Thank you.