The answer lies in the Vuduri inability to think outside the box. Normally, they would use infrared to detect the heat signature of the vessel. What they failed to appreciate was that the metal hull of the Ark was sitting at minus 80 degrees Celsius initially, the temperature of space, so it literally did not have a heat signature.
Second, they would use MIDAR in ground-penetrating mode and they did but it never occurred to them to scan the stands of cane-trees. After all, who would land into a clump of trees?
Finally, they would use visual inspection but the Ibbrassati had taken the time to cover the Ark in camouflage netting along with cane-tree leaves and bark so it would blend in visually.
The Vuduri gave up. They knew the colonists would turn up eventually but it was their lack of imagination that prevented them from finding the gigantic Ark II after the crash landing in the first place.
Entry 1-346: December 6, 2013
The Tightbeam
As mentioned numerous times in Rome's Revolution, the Vuduri communicate mind-to-mind using gravitic modulation. How fast is this? Nobody knows. Nobody has measured the speed of gravity. Nobody has ever seen a graviton or proven that it even exists. But for the purposes of the world of the Vuduri, we assume that gravity waves travel at a speed of 10 x 1030 meters per second which is much, much faster than the speed light, which is a measly 2.998 x 108 meters per second. In reality, most modern theorists believe that gravity is not carried by a particle but rather is just a deformation in the fabric of space-time. The effects of this deformation can be detected the same as any other phenomenon which means they believe that gravity travels at the speed of light.
But the world of Rome's Revolution is science fiction so I can postulate anything I want as long as I don't know it not to be true. Nobody has measured the speed of gravity so I'm sticking to the higher speed for now because it makes for a better story.
Anyway, the point of all of this is the Vuduri have harnessed the speed of gravity to enable communication. They use a device called a tightbeam which is built from Casimir Pumps to create a focused beam of gravitons, using digital pulses to carry information. All the Towers of all the cities of Earth are connected by tightbeams. Also, Earth communicates with its space vessels, colonies on Mars and other places using tightbeams.
Why not just use the apparatus built into their heads? It is because sometimes machines (e.g. computers) need to communicate and the amount of data to be transmitted is vastly larger that a human can process and is completely unintelligible. But doesn't this violate the Vuduri directive against computers having access to Casimir Pumps?
The answer is no. The Vuduri have built a very simple, metered interface with is electromagnetic on one side and contains the gravitic modulator on the other. A computer could no more use it to become unleashed that a person could use a lighthouse light to guide their car down the road. It is special purpose and can only be used for what it was designed for.
OMCOM adapted the concept into his null-fold relays, as seen in the The Ark Lords and Rome's Evolution but despite the fact that he has broken all the Vuduri laws, even he uses them only for communication.
Entry 1-347: December 7, 2013
Vuduri Programmers
As mentioned numerous times in Rome's Revolution, a "normal" Vuduri would not speak aloud. The Vuduri language is used for written items, computer interfaces and the occasional interaction with the mandasurte.
But what about computer languages? Do they use FORTRAN? Visual BASIC? Java? Or something similar but with a Vuduri flavor to it. As a programmer myself, I am very interested in this question but every time I ask them, they defer answering.
The reality is Vuduri computers such as OMCOM are not programmed in the conventional sense. When Rome was challenged to build a computer to house her Library in The Ark Lords, she claimed she could not do it without an initialization module, which is to say a bootstrap operating system.