In netrek a ship which carries armies normally has much greater value than the other ships. The value comes from the necessity to have kills in order to pick armies, the typical scarcity of armies, and finally because carriers are potentially capable of taking enemy planets.
If the enemy team knows (or guesses) that a ship has picked armies, it will attempt to kill that ship whenever possible. That is why it is essential that a carrier is assisted by its teammates. This is especially important when the carrier is headed to take over an enemy planet.
To quote Red Shirt's teamwork guide:
The proto-typical good escort is the guy that gets to the target planet a few seconds ahead of you (even though you go at maximum warp), kills the nearby defender (if any), and positions himself between the planet and any onrushing enemies so they can't get at you while you orbit. It's like a screen in basketball, except for the part about killing.Have a look at this play to see what a good escort is expected to do.
Killing the enemy base is usually achieved by simultaneous synchronized ogging by several players of the team. "Ogging" is the process of sacrificing your ship in order to kill or damage an enemy. It is usually achieved by cloaking, maneuvering close to the intended target and finally uncloaking, firing at the enemy, and exploding close to him. All this could inflict serious damage if executed properly.
As Starbases are much more powerful than the other ships, they cannot really be damaged by single player oggs. It is essential that at least several players take part in the ogg and that they attack the base simultaneously. A simultaneous attack saturates the defenses of the base, and allows much greater damage to be caused by the same ships.
Have a look at this ogg for a good example of synchronization. Now look at the same ogg, but only on the galactic map and observe the player flow.
ttonchev@mit.edu