Freelance Traveller

The X-Boat Network

by Greg Nokes

This article originally appeared in the May/June 2026 issue.

Overview

The X-Boat Network provides mail and small package delivery across the Imperium and beyond. The Express Boat Network is the single most important duty of the Scout Service performed by its Communications Office within the Imperium. 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.

System Components

X-Boats

The express boat (xboat) is the key to the Imperial communication network. These are Jump-4 ships with no maneuver drive, crewed by single pilots. X-Boats ply the express boat routes between systems, spending a week in jump followed by a short time in-system getting refueled and transferring messages and small parcels. There is a one ton cargo bay which is occasionally used to carry vital cargo such as vaccines or sophisticated repair parts. Rumors abound that X-Boats can also carry sophonts on missions for the Imperium.

X-Boat Tenders

Express boat tenders are jump capable, and each may carry up to four xboats in its cavernous ship bay. X-Boat Tenders meet the X-Boats in the outer system and provide fuel, data, and parcel transfer services, as well as relief for the X-Boat pilot or replacement crew. The tender also carries data banks which relay messages to the xboats just before they leave for the next system. It also carries replacement pilots for the xboats. The Tenders operate in small fleets, generally with at least 3 on station - one arriving, one handling inbound X-Boats, and one departing.

Couriers

Scout/Couriers

Scout/Couriers are used to carry any physical parcels in-system and to reach systems not directly served by the main X-Boat routes. When a message can no longer be forwarded by xboat along the major routes, it is transferred to a scout/courier or to a Subsidized Merchant which then carries it to the specific world in question.

Subsidized Merchants

While not direct members of the X-Boat network, subsidized merchants hold a small amount of their cargo space (generally 5 tons) as a mail vault which can hold parcels and message storage for transfer from stations to remote systems. This is called "Book Rate" shipping. It is normally transported by X-boats although subsidized merchants, tramp freighters, couriers, and many other kinds of vessels may take mail contracts. This system slowly moves messages and parcels at about 1 parsec per week from X-Boat stations out to nearby systems.

X-Boat System Operation

The entire network operates like the pony express — messages are always moving at top speed. Transfer time for messages from one xboat to a tender can be as short as minutes, and is rarely more than an hour.
There are three general types of messages which the X-Boat network can carry: broadcast messages (bMessages), targeted messages (tMessages), and small physical parcels.

Parcels

Small packages can be shipped via the X-Boat network. There is a one ton cargo bay which is occasionally used to carry vital cargo such as vaccines or sophisticated repair parts. Physical parcels cost 1 Cr per gram per hop and are limited to 2 kg maximum weight.

Network Performance

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, nearly four parsecs per week is obtainable. In practice, this speed is somewhat reduced by the fact that routes do not follow straight lines and that not all jumps are made at Jump-4. Nonetheless, the system achieves an average of about Jump 2.6 per week.

Network Coverage

The X-Boat network is a general framework of routes connecting major worlds and population centers with other worlds. Economic considerations make it impossible for the network to reach every single world in the Imperium. Main routes are plotted to come within several parsecs of many star system in the Imperium, so the added transit time is rarely more than an extra three or four weeks when using Scout/Couriers or Book Rate for final delivery to off-route systems.

The system will make intelligent choices on routing, and often will send messages via several routes in case of unforeseen issues.

Using the X-Boat Network

Sophonts within the Imperium can use the X-Boat network for nominal fees. Most of the cost of operations is covered by the Imperial government. There are also "shadow" X-Boat networks that are regional or special purpose, such as Turkura Line's J-6 Courier system, however the X-Boat network covers the largest areas. There are also rumors of a planned upgrade to the network, refitting the ships with TL16 data storage and J-6 drives, however there is no evidence.

Broadcast Messages (bMessages)

bMessages are intended for a single person or group of people who are on different systems or whose exact location is unknown. A bMessage is held on the tender and transferred to each X-Boat departing for a system which has not received the bMessage. As the bMessage arrives in a system, it will be transferred to the tenders and then forwarded again. It will have a cryptographic signature which means that it can only be opened by the target sophonts.

The scope of a bMessage is defined by administrative zones rather than hop counts, making it easier to estimate costs and coverage.

bMessage Options:

• Broadcast Scope: Messages are sent within defined administrative boundaries:
  • Cluster (1-2 parsecs): Local neighboring systems
  • Subsector: Regional administrative area
  • Sector: Major political/commercial region
  • Domain: Four-sector administrative region
  • Imperial: Empire-wide broadcast
• International Mail: If the bMessage is tagged as International, it will be transferred to other express boat-type networks outside of the Imperium. No guarantees that the message will reach its intended location are given.
• Priority: Can be set to high (hPri). If hPri is set, the X-Boat will tight-beam the message and all other hPri messages upon jump exit to the closest Tender. This may cut a day off the intersystem message transfer time. If hPri is not set, the messages will be transferred in bulk during regular refueling operations via high-speed network interconnections.
• Message Persistence: bMessages will be held for approximately a decade. When they are opened, a delete message is propagated back into the network.

bMessage Costs

bMessage pricing is based on administrative scope, with multipliers reflecting the increased network load of larger broadcast areas:

• Cluster: 2 Cr (1 Cr base × 2 broadcast multiplier)
• Subsector: 4 Cr (2 Cr base × 2 broadcast multiplier)
• Sector: 16 Cr (4 Cr base × 4 broadcast multiplier)
• Domain: 192 Cr (32 Cr base × 6 broadcast multiplier)
• Imperial: 768 Cr (64 Cr base × 12 broadcast multiplier)

Add 10 Cr to the base cost for hPri priority, and a flat 100 Cr per international network that the message will transit.

Book Rate

Book rate messages slowly spread 1 jump away from each station via merchant vessel or Scout/Courier about each week. Book rate delivery is used for systems not directly connected to the main X-Boat routes.

Example: Enri is on Regina on 1105/100. He knows that Kipu is somewhere in the subsector, so he purchases a subsector-wide bMessage for 4 Cr. The message will be distributed to all X-Boat stations within the Regina subsector.

Kipu is on Menorb, and she receives the message via book rate on about 1105/132. As she opens it, a delete message is dispatched back through the system to remove the message.

Targeted Messages (tMessages)

tMessages are used when you know where someone is located. The message will travel the X-Boat network to a specific station, where it will wait to be opened. tMessage costs are based on distance:

• Cluster (1-2 parsecs): 1 Cr
• Subsector: 2 Cr
• Sector: 4 Cr 
• Domain: 32 Cr
• Imperial: 64 Cr

hPri can be set for an additional 10 Cr, and international transfers have a 100 Cr fee per international network that the message will transit. Book Rate delivery to off-route systems may incur additional delays but no extra charges.

Example: Kipu drafts a reply to Enri and dispatches it back to Regina within the same subsector. This will cost her 2 Cr, and it will take about 4 weeks to arrive.