Large Scale Fleet Combat

[phavoc]

Invading another system with a fleet is tricky business. Assuming your target is protected by the 100D rule, you won't really be able to surprise them because you have to emerge too far away for that to work.

Plus you still have the random factor affecting your fleet arriving in enemy space. Which means you won't know how much of your fleet is popping out of jumpspace when you first emerge.

I would think your fleet would emerge far enough from the defenders to allow you time for everyone to emerge and get ready for combat. While HG is mum on this idea, Sector Fleet talks about a device that can simultaneously jump a fleet with only a few hours window for all of the ships to arrive in.

And unless you know you are going to win, I would think that a fleet would jump into an enemy sector and first refuel before proceeding to the main world. Fighting on empty jump tanks means you are staying put in that system no matter what the outcome of the battle. And a defended world is going to have meson sites that will make it suicidal to try and refuel on-world until they have been silenced.

 

[phavoc]

Ok, here is what Mark Miller wrote in volume 24 of the JTAS on jumping and speed/direction of the ship prior to entering jumpspace:

"The laws of conservation of mass and energy continue to operate on ships which have jumped; when a ship exits jump it retains the speed and direction that it had when it entered jump. Commercial ships, for safety reasons, generally reduce their velocity to zero before jumping. Such a procedure eliminates some of the danger of a high velocity collision immediately after leaving jump. Military ships and high speed couriers often enter jump at their highest possible speed, and they aim for an end-jump point which directs their vector toward their destination in the new system. Such a maneuver allows constant acceleration in the originating system, followed by constant deceleration in the destination system.

An additional complication is imposed on ships when the two star systems involved have a higher proper motion with respect to each other. In that case, a ship must take into account relative velocity between the two, when computing speeds and directions."

 

[kristof65]

Furthermore "spy" vessel in a system 4 parsecs away, upon seeing a fleet accelerating at 6G

There won't be any spy vessels to warn anyone as they'd be blown away.

Really? Space is too big for an invading fleet to be detected fast enough to do anything about it, but a single spy vessel will automatically get blown away?

A spy vessel doesn't have to be anywhere near the traveled or populated portions of a star system in order to monitor fleet movements. Sitting only 10 light minutes above the stellar plane still allows them to see a lot, yet gives them more than enough time to leave the system (or even jump elswhere in system) before they can be engaged if they are detected.

A single vessel using no active manuevering and passive sensors is going to be very hard to detect, in stark contrast to detecting an accelerating fleet of multiple ships.

Also, you are unclear on a planets jump shadow. It creates no "corridors" only a spherical volume.

No, I'm very clear on that. If I'm unclear on anything, it's using the term "corridor" simply because I couldn't think of a better term. So let me give a more literal example.

Imagine a bead hanging in mid air, representing your naval depot. With nothing else around it, an attack can come from anywhere, such as you're suggesting. Now, take a basket ball to represent the star's jump shadow, and place it right next to that bead. Suddenly you've cut off a significant portion of where attacks can easily come from. Take a large marble and place it on the other side of the bead to represent the jump shadow of a gas giant. By placing a depot in such a place, you've effectively limited your attacker's options - which make it easier for the spy ship above to calculate if an outgoing fleet is headed on a likely vector to be a threat.

Military planners will look at things like that when deciding where to place depots and bases, and use them whereever possible.

Bottom line, the defenders won't know when. They will just know that they are subject to, at anytime. Like I posted earlier, a few planetoids accelerated to intra-system travel speeds (which are higher than I listed) and bye, bye parked ships. Unless you have something specific that you have not yet posted, you have no credible defense.

Defenders who don't pay attention or become complacent won't know when. Defenders who take active measures, such as smart placement of their bases, good intelligence gathering, and the use of spy ships to monitor neighboring systems have a much better chance of getting early warning. Even just 10 minutes of early warning can make a world of difference in the outcome of an attack.

 

[DFW]

and the use of spy ships to monitor neighboring systems

There are no spy ships in an otherwise empty system with a naval depot.

And, you are coming from an empty hex...

 

[kristof65]

I didn't say putting spy ships in your opponents depot systems. I said using them to monitor neighboring systems around your own depot.

 

[DFW]

I didn't say putting spy ships in your opponents depot systems. I said using them to monitor neighboring systems around your own depot.

Won't do any good as you aren't coming from a system into the enemy depot...

 

[kristof65]

Won't do any good as you aren't coming from a system into the enemy depot...

From the attacker's point of view? Ideally, yes. Realistically? Probably not.

You're talking about jumping in from an empty hex. But you first have to get to that empty hex. Which means carrying enough fuel for two jumps, possibly three jumps to make sure you can get away. A fleet with all J6 capable ships and able to carry enough fuel for 3 jumps would be hard to defend against. But it's also almost impossible to build under the Traveller rules.

No, the average fleet is only going to have a J3 or J4 average. Which means they're generally going to have to go through at least one system within J6 of the depot you're looking to defend.

So the ships in the attack fleet don't go through that system all at once. Maybe they go through in small groups, or through neighboring systems. They're still building a pattern that can be read, and put possible targets on notice. Precautions will be taken by the defenders - moving fleets, changing orbits, etc.

Yes, with enough proper preparation, an attack could be a 100% surprise on the defender. The enemy could spend years positioning fuel tanks at deep space rendevous points, and months assembling a major fleet at that point one ship at a time. But all that goes back to one of my original points - that intelligence gathering is one of a navy's most important strategic resources. Because no enemy can move those kind of resources without leaving behind signs. Even if what they are doing is building a couple of jump capable rocks to smash into a planet.

Almost all "surprise" attacks are successful because the target is complacent and unaware, and/or ignoring/misinterpreting the intelligence data they do have. The signs for Pearl Harbor where there well before the actual attack began. Likewise with North Korea's invasion of South Korea. And even the WTC attacks on 9/11.

 

[DFW]

Won't do any good as you aren't coming from a system into the enemy depot...

From the attacker's point of view? Ideally, yes. Realistically? Probably not.

You're talking about jumping in from an empty hex. But you first have to get to that empty hex. Which means carrying enough fuel for two jumps,

:lol: Sorry but, it's a good thing you aren't really in charge of defending a fleet. Read more threads & and maybe Reft material.

Like I said; say bu, bye to your parked fleet.

 

[phavoc]

If you need to park a fleet, you would want to do it closer in to the primary star. For our system you could use Venus, or even Mercury (on the side away from the sun obviously!). Put your station(s) in orbit and park the rest of the ships in geostationary orbit. Both planets are deep within the 100D radius of our sun (a G2). If you had a larger sun (F,A, B or O) the radius is even farther.

An attacking fleet has to enter realspace far enough away that you would have time to activate your defenses. Plus a fleet will need time to ensure all of its ships have re-entered the system and re-group. Assuming an attacking fleet has built up a ballistic velocity, having 1/3 or even 1/2 of your ships being delayed to re-entry to realspace by just an hour, well, your fleet won't be able to attack as a single body since the emerging vessels will be far behind the ones that came through first.

In theory if you had a 'dirty' system with a lot of asteroids in it, it would make it hard for a jumping ship to re-enter with high velocities. But, since most all planetary bodies, including asteriods, tend to be on the plane of the elliptic, the attackers would just jump in above or below that and avoid most of the asteroids.

The rules say that you enter realspace with the same course and speed as you left. And, it would seem from anecdotal evidence, that jumpspace travel is done in a straight line between entry and exit points. Though the rules have simplified things so that you don't take that into effect. It would be interesting to try and come up with rules that would take into account say a longer jump-4 that took you through hexes where systems were already present. It would mean potentially that you would spend a lot more time in realspace maneuvering to a clear jump point.

 

[kristof65]

:lol: Sorry but, it's a good thing you aren't really in charge of defending a fleet. Read more threads & and maybe Reft material.

Like I said; say bu, bye to your parked fleet.

So you ignore half of what I say in most of my posts, then attack me personally?

 

[DFW]

:lol: Sorry but, it's a good thing you aren't really in charge of defending a fleet. Read more threads & and maybe Reft material.

Like I said; say bu, bye to your parked fleet.

So you ignore half of what I say in most of my posts, then attack me personally?

Hardly. The "half" I didn't bother addressing was irrelevant as it has been addressed numerous times in different threads and isn't worth digging into the science once again. And, it isn't personal at all as none of us are REALLY going to be in charge of defending a fleet. Lighten up.

Have a great (and hopefully) globally warmer, Christmas.