MOVREP. 
The USS Indianapolis dropped off the a-bomb, and left for it's classified next port. Noone knew her schedule, noone tracked her. So when she was sunk, noone knew to look for her. Because of that, we now have to file movement reports. We list all waypoints of each transit, and the scheduled arrivals at each. If we are more than 4 hours ahead of or behind our Plan of Intended Movement, then we have to send a new MOVREP. That narrows a missing ship down to an 8-hour window at PIM-speed (typically 15 knots or less, so within 60 nautical miles of where we should have been, if 15 is PIM-speed. 

That also allows Optimum Track Ship Routing, or weather diversion. The weather guessers look at your track (preplanned course-line), compare to weather report, and make recommendations for diversion if necessary. 

I recall a story I was told by an AG-2 (Aerographer's Mate second class, E-5 Navy meteorologist), during a wargame, a ship falsified it's posit for WEAX (daily weather reports from the ship to the nearest naval weather station), AND read the WEAX of the opfor ship to figure out where they were. 

So a Tigress on normal ops should not be able to disappear. It almost *has* to be a major misjump if the Imp Navy isn't pounding the bushes in every nearby system within 184 hours of it's last report. 
From: "xxxxxx@comcast.net" <xxxxxx@comcast.net>
To: TML <xxxxxx@simplelists.com>
Sent: Thursday, February 11, 2016 11:56 PM
Subject: Re: [TML] Instant city

Hello again Greg Chalik,
 
The Tigress-Class Dreadnaught as mentioned has a crew of 19,512 and is on long deployments with a Model/9 fib computer. I image that there are courses that would allow post graduate work in any field to be accomplished by any crew member who is interested.
 
There is going to be a long delay before someone notices that the Tigress-Class dreadnaught has gone missing because of the 168 +/- 16 hours, if a miss jump has not occurred, required to complete a jump which causes a communications delay.
 
If the next port of call knows when the Tigress-Class Dreadnaught is due to arrive and the ship does not show up the port sends a message to the previous port which takes another 168 +/- 16 hours. The last port the Tigress-Class visited sends back a reply saying the ship left approximately 336 hours earlier, which when the message gets back to the destination system the time has now elapsed to approximately 504 hours. If the ship's next port of call was going to be a surprise visit no one their would report the Tigress-Class Dreadnaught not arriving.
 
Depending on how many ports the ship was to visit before reporting to an IN base could be months before anyone notices.
 
Jump Drives occasionally, even though they've been around for a while, still miss jump and if the ship is lucky returns to normal space in a system they can refuel, figure out where they are, and the jump drive still works.
 
Where will the IN search for their missing dreadnaught after a couple of months, especially if the ship miss jumped?
 
The outline that started this topic thread gave only the information that a Tigress-Class Dreadnaught managed to land on a populated world and the native began using the hull as a city. The Referee/scenario designer can fill in the blanks about how much damage was caused by the landing. Basically I cannot give a good response since I don't have enough information to say what is plausible in the TU as opposed to the real world.
 
Yep, I'm copping out and you do have valid points.
 
Tom R