Express Boats (a.k.a. X-boat) are rapid communication ships which are designed to make optimum use of jump technology in communicating information within the Imperium. Because the Imperium is so large, ordinary communication must depend on ships travelling along established trade routes, making Regina (Spinward Marches 1710) nearly 4 years out from the Imperial Core.
The express boat (abbreviated X-boat) system, established originally in 624 and expanded to cover the entire Imperium by 718, cuts this communication time by nearly 75 percent. Selected locations along major trade routes are established as sites for express stations, which are orbital facilities which service and refuel the X-boats on their communications runs.
As an X-boat arrives in a system, it beams its recorded data to the express station, which then retransmits it to an X-boat standing by for a jump outsystem. Time between jumps is almost always less than four hours and has been recorded at under seven minutes, making the speed of communication nearly the speed of jump (since X-boats carry jump-4 drives, speeds near four parsecs per week). In practice, this speed is somewhat reduced by the fact that trade routes do not follow straight lines and that not all jumps are made at jump-4. Nonetheless, the system achieves approximately jump-2.6 per week.