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Vagrant-class X-Boat Service Hull

This article originally appeared in Issue #013, January 2011, of the downloadable PDF magazine.

Based on an idea and input from “Patron_Zero” and Citizens of the Imperium discussion thread http://www.travellerrpg.com/CotI/Discuss/showthread.php?t=23105


Gan Kuuda looked at the specification sheet on his desk and shook his head. “That’s, uhhh, very nice, but what do you want me to do with it? I don’t really have time for another project, sir. The final design for that Oberlindes lighter is due in a month and someone…” The pause was obvious, as was the stare at his supervisor. “…keeps adding things to the final specs. And I told you that a PAW, even a small one, wouldn’t fit in that Spectre-class fighter, so now I’ve got even less time to straighten that mess out.” His voice rose in pitch and volume before he could stop himself. He stopped, his mouth clamping shut audibly.

There. He’d probably sealed his fate and fully expected to be unemployed in the next few moments.

His boss, Eneri Uurkamm, simply smiled back across the desk at him. “Now, now,” he chided gently, knowing how to massage talent when it needed it. “You’re the best I’ve got, and this has to happen fairly soon. Look, here’s the deal.” Eneri said, running a hand through his hair. “Do you remember that redhead I was dating? You know, the one with … anyway, she’s a secretary over at IISS sector headquarters, works for Scout Leader Tollefson. He’s the senior procurement officer over there.” Eneri glanced around conspiratorially, and then leaned over the desk. “She says she’s seen several memos come through talking about the fleet upgrading to the R series X-boats because the M series has developed a problem with structural metal fatigue. So they’re selling off all of the M series in service, across the sector. That’s where this beauty comes in.” He finished, jabbing a finger down on the data slate.

Kuuda sighed and picked up the slate, wishing that Uurkamm would come to the point. The specs were mildly interesting – a service hull that could be mated to an X-boat, giving it maneuver capability and additional cargo space, while the X-boat gave the service hull jump capability. “Okay, it’s an interesting idea,” he said, tossing the slate back onto the desk with a clatter. “But who’s going to buy what is essentially a 100 ton ships boat that doesn’t dock to anything but an X-boat?”

Uurkamm smiled wolfishly. “We make it modular, and then let them figure it out. Who knows, we can market it to belters, free traders, adventurer types, the salt of the earth…you know, morons.” The hook had been taken, and now it just needed to be set. “I’ll throw in a 20,000 credit bonus, if that’d help.”

Sighing yet again, Kuuda nodded. His wife had wanted to visit her mother on Jazep anyway, so he could give her a high passage for her birthday. “All right, all right. I’ll see what I can do.”


Since its inception, the X-boat has been a single purpose design – to carry messages as efficiently as possible along the communication routes of the Imperium. Normally, X-boats reaching the end of their service life are parted out and scrapped. Some few are sold to client states and megacorporations, but this has been the exception, rather than the rule. This was the situation in late 1070 when circumstances changed somewhat.

The IISS sector commander in the Gushemege sector ordered an upgrade of X-boats currently older than 20 years when it was discovered that some models were showing signs of metal fatigue. There is some speculation that the commander had contacts with some of the shipyards in the sector, and was perhaps getting kickbacks for such a move. Later investigation did reveal that the majority of the shipbuilding contracts went to Ling Standard Products shipyards, but no criminal charges were filed.

Regardless of other circumstances, this created a massive surplus of X-boats in the Scout Service’s inventory, far more than could be used for parts locally. In an effort to ‘clear the books’, many of these X-boats were sold cheaply (some as low as 10-20% of their original value).

A minor naval architect’s office on Kamurinmur got advance notice of the surplus boats, and gambled on an idea. In an effort to make these surplus X-boats useful for other tasks, a secondary hull was designed, incorporating maneuver drives, additional cargo area, weaponry, and capability for fuel skimming and surface interface operations. This design delivered all of the above, but as with all such add-ons, had a few issues.


Game statistics are included for several of Travellers’ rule sets. Included below are stats for Book 2 CT, High Guard, and GURPS: Interstellar Wars.

Base Statistics

Annular wing/ring - 24 m diameter, 5 m tall, 3 m wide. Volume 750 m3, 55 dtons.
Drive pods (x3) - 6.6 m diameter, 11 m tall. Volume 250 m3 (x3), 55 dtons.
The pods and ring overlap 150 m3 total, for a total volume of 100 dtons.
The airlock on the service hull connects directly to the existing airlock on the boat; the only real modification required to an X-boat is the addition of the control, power, and fuel lines that are contained in the 3 retractable docking clamps.


Classic Traveller – Book 2

Using a 100-ton hull, the X-boat Auxiliary Service Hull is a companion ship sold to better utilize surplus and retired X-boats, giving them maneuver capability, gas giant refueling, and atmospheric landing capabilities. It has maneuver drive-A, and power plant-A, giving performance of 2-G acceleration on its own, and 1-G acceleration when mated with an X-boat. There is fuel tankage of 10 tons supporting the power plant. When docked with an X-boat, the pair can perform Jump-2. Adjacent to the bridge is a computer Model/1. There are three staterooms in the standard configuration. One turret is installed, mounting a mix of beam laser, missile launcher, and sandcaster, with 1 ton of fire control installed. The ship has no vehicles. Cargo capacity is 51 tons, although typically this space is used for job-specific customization. The ship is streamlined.

The service hull requires a crew of 3: pilot, engineer, and gunner. The pilot also acts as the navigator. The ship costs MCr47.1 and takes 9 months to build.


Classic Traveller – High Guard
Ship: X-boat Service Hull
Class: Vagrant
Type: Auxilliary Boat
Architect: Navanod
Tech Level: 13
USP QB-1602311-030000-20002-0 MCr 35.180 100 Tons
Bat Bear        1     1   1   Crew: 2
Bat             1     1   1   TL: 13
Cargo: 45.000 Emergency Low; 1 Fuel; 3.000 EP; 3.000 Agility; 2
Fuel Treatment: Fuel Scoops and On Board Fuel Purification
Architects Fee: MCr 0.352 Cost in Quantity: MCr 28.144
Detailed Description
Hull: 100 tons/1,400m3, Annular Wing
Crew: 2 (Pilot, Gunner)
Engineering: Jump-0, 2-G Manuever; (Jump-2, 1-G Maneuver when docked to X-boat), Power plant-3, 3.000 EP, Agility 2
Avionics: Bridge, Model/1 Computer
Hardpoints: 1 Hardpoint
Armament: 1 Triple Mixed Turret with 1 Beam Laser (Factor-2), 1 Missile Rack (Factor-2).
Defenses: 1 Single Sandcaster Turret organised into 1 Battery (Factor-3)
Craft: None
Fuel: 3.000 Tons Fuel (0 parsecs jump and 28 days endurance), On Board Fuel Scoops and Purification Plant
Miscellaneous: 3.0 Staterooms, 47 Tons cargo
User-defined: None
Cost: MCr 35.13 Singly (incl. Architects fees of MCr 0.351), MCr 28.104 in Quantity
Construction Time: 38 Wks (30 Wks in Quantity)


GURPS Traveller Interstellar Wars
Tech Level 11
Hull 100-dton Annular Wing Airframe hull, dDR 10 armor.
Systems 5 Maneuver Drive, Small Bridge, Model-1 Sensors (Scan 16), 1 Light Turret, 1 Beam Laser, 1 Missile Rack, 1 Sandcaster, 8 Fusion Power, 3 Stateroom, 69.5 Cargo
Statistics EMass 163.3 tons, LMass 167.3 tons, Cost M$35.91, SM +8, ASig +1, Hull dHP 27, Life support capacity=6, sAccel 5.98 (~3 G when docked with X-boat), no jump capacity (Jump-2 when docked with X-boat), Top Air Speed 4,400 mph.
Crew Pilot (1 officer), Gunner (1 rating). Total 1 officer, 1 rating.


The Vagrant-class Service Hull is built as three oblong spherical pods arranged around a central annular ‘wing’. The central wing is built as as torus (outer diameter 24 meters, inner diameter 21 meters) with an elliptical cross section 3 meters wide and 5 meters high. The main deck forms a corridor roughly 3 meters tall, with the approximately 2 meters below the deck being utilized for fuel tankage, fuel purification, grav plating, and other sundry wiring and plumbing.

Each of the three pods is an egg-shaped spheroid 6.5 meters in diameter and 10.5 meters tall. They are divided into 3 separate decks with roughly 3 meters of separation. The portion of the pod below the lowest deck, roughly 1.5 meters high, houses a single large landing gear well, the actuation hydraulics, and additional power plant machinery. Iris valves in the floor and ceiling are located in the center of the pod, with access ladders mounted as required.

The Annular Wing

The central wing mounts a variety of ship systems. Beneath the deck plating are mounted 3 – 1 dton fuel tanks, located adjacent to the fuel scoops on the outer edge of the hull and the fuel purification systems tied into each tank. The inside of the wing mounts an airlock with an extendable passage tube that connects to the airlock on a standard X-boat to allow personel transfer when the ships are docked. Also mounted on the inside of the ring are 3 docking/umbilical arms. These arms lock the X-boat in place, and special fittings connect to the X-boat to allow the transfer of fuel as well as allowing the joined ship to be controlled from the X-boats bridge. A cargo hatch is located counter-clockwise next to Pod One, opening in the lower hull. Temporary deck plates cover this hatch; they are taken up and stowed when loading cargo.

Pod One

Pod One is designated as the pod carrying the ship’s bridge on the upper deck. If the ship mounts weaponry, it is mounted on the hardpoint located outboard on the central deck, with the gunners’ position located adjacent to the turret. Also found on the central pod deck are the ships’ computer, the ships’ locker, and a fresher for use by the command crew. The lower deck contains a pair of maneuver drive units, one of the ship’s three power plants, life support equipment, and an airlock for use when the ship is landed.

Pod Two

Pod Two is designated as the pod counter-clockwise from Pod One. The main deck of Pod Two is typically used as a stateroom (typically the Captains’, due to its larger size and walls that are almost vertical). A wall divides the stateroom from the pods’ iris valve, and provides a privacy door as well. The upper deck of Pod Two is typically a stateroom as well, although the dome shape of the upper deck limits usable space, making it seem cramped even with the two large windows looking inboard and outboard. As with Pod One, Pod Two’s lower deck contains a pair of maneuver drives along with another power plant and airlock.

Pod Three

The remaining pod is designated as Pod Three. The upper deck contains another stateroom, similarly cramped as described above. The main deck of Pod 3 is allocated typically as a crew lounge. The lounge houses the provisions, cooking appliances and materials, laundry facilities, and various entertainment devices to keep the crew occupied. The lower deck is similar to that of the other pods.


No design is perfect, and the Vagrant-class is no exception. The most common complaint is the cramped quarters of the upper pod deck staterooms. Only a 4 meter diameter circle in the middle of the room allows an average sized man to stand upright due to the slope of the walls, a significant portion of which is taken up by the iris valve in the floor. The fresher is a particular problem, with the design requiring one to sit to use the toilet facilities, and stoop while using the shower.

Another issue is that of cargo space within the central wing. It is rather narrow, a fact not helped by the slope of the walls. Standard cargo containers cannot be used at all; the standard cargo hatch is limited to objects less than 1.5 meters wide and 3 meters long, generally limiting it to carrying cargo in crates or on pallets. Special half-dton containers have been developed for this class of ship, but are very uncommon. The fact that this cargo area is the only connection between the pods further complicates the matter, making bulk cargoes difficult to haul. Machinery from the docking arms and fuel scoops intruding into the corridor space complicate matters further.


Despite the shortcomings listed above, the Vagrant-class does have some substantial benefits aside from the design specifications it was built to.

The most obvious benefit is the arrangement of drives, power plant, and fuel tanks. All of these systems are basically triple-redundant, giving the ship a reputation for durability. Generally, only a catastrophic failure renders all drive systems inoperable.

The ships large circular landing pads give it a relatively low ground pressure, allowing it to land on many unimproved surfaces. This makes it very useful for travels in the wilderness.

The Vagrant-class was designed from the ground up to be as customizable as possible. When it was designed, several basic variants were included in the plans, allowing the user maximum flexibility. Attachment points for additional partition walls or bulkheads are placed every 4 meters on the ring to allow the creation of holds, fuel tanks, rooms, and more. Deck attachments exist for passenger couches, wall lockers, and various other equipment. The Vagrant is designed to be whatever it’s owner needs at the moment.


System Transport: Given its lack of jump drive, some Vagrants have been outfitted for orbital and short system transport. The central ring is outfitted with up to 70 passenger couches (including life support), leaving 12 dtons of cargo space for luggage and cargo. The crew lounge and captains stateroom are converted into passenger lounges, while the upper decks of pods two and three are set up as observation lounges. The turret and fire control are removed, with the resulting space being converted into a galley for the ship’s stewards.

Mining Rig: Some belters have converted Vagrants into mining ships by replacing the docking arms with manipulator arms. Both sets are designed to utilize the same controls, so a mining rig usually attaches the docking arms for transport to its work area, then switches them out for the manipulator arms. When stowed as cargo, either set takes up 5 dtons. Typically, the weapons in the turret are replaced with a mining laser, and the ring section has additional hatches added to receive the raw ore. The ring between pods one and three is left open for normal passage; walls are added to section off the remaining area into ore holds. Pod two is either used as additional ore storage, a hangar for a mining buggy, or set up as a mini-refinery.

Fuel Tender: In some cases, the Vagrant is converted to a flying fuel tank for an X-boat. The ring section between pod one and the main airlock is sectioned off, and the rest of the ring (along with pods two and three) are converted to fuel tankage and fuel purification. Such an arrangement reduces available cargo space to 16 tons but adds an additional 40 tons of fuel and 1 ton of additional purification equipment to the paired craft, allowing two successive Jump-2s as well as faster fuel purification. A few of these have been used as rift couriers.

Lab ship: Several Vagrant-class hulls and X-boat pair hulls were purchased by various science foundations and converted to small lab ships. On these, the captain’s stateroom and crew lounge are converted into labs, while the other two staterooms are retained for use by researchers. Fire control and the turret are removed and the space converted to additional computer hardware or storage. While not nearly as effective as a full-sized lab ship, this option is significantly cheaper.

Case Study: The Hippity-Hop To It

One example of the Vagrant-class in action is a ship operating in the Islands Cluster, known as the Hippity-Hop To It. Originally built on Ethbray (1722 Gushemege) in 1095, the service hull was purchased by Captain Lewis Tolliver, a belt miner. Outfitted as a mining rig, he worked Ethbray belt for ten years until he fell victim to radiation poisoning from a solar flare. Before he died, he willed the ship to his first mate, Eneri Gaetano. Captain Gaetano worked the belt for an additional year, finally hitting his ‘big strike’ – a rouge planetoid in the outer system, loaded with precious metals. Using his most of his newfound wealth, he purchased a surplus X-boat , hired a crew, refit his ships, and set out to find adventure. He renamed the service hull Hippity, and the X-boat Hop to It.

A year of travel and trade led the ship to the Cyclone system at the very edge of the Great Rift. During the jump to Eskandor, a largish micro-meteorite penetrated the hull of the X-boat and struck the jump drive, causing a misjump. The Hippity-Hop to It emerged from jumpspace in a remote section of empty space. While the rest of the crew began to attempt repairs, Captain Gaetano calculated their new position and was surprised to discover that they were in hex 2025 in the Old Islands subsector. The engineer managed to patch up the damaged drive, and luckily the Hippity was configured to carry an additional 20 tons of fuel. Holding their breath, the crew plotted the course to New Home and fired up the jump drive. Upon arrival, it was clear there had been a second misjump—the Hippity-Hop To It had been in jumpspace for nearly a year, although it had seemed only the normal week to the crew.

Winding up in the Islands presented a major problem for the crew – they had precious little cash to pay for repairs. They did, however, have a cargo hold full of silk and alcohol purchased on Cyclone, which was sold off for a moderate profit. The Hop To It was repaired in short order, and the ship began trading in the Islands full time. The pilot, Urrlikar Gashmme, left the crew to return home to the Imperium, and a replacement pilot, native Islander Tal Anderson, was hired. Since then, the group has managed to become entangled in Island politics, working occasionally as eyes and ears for the New Home government.

The Crew of the Hippity-Hop To It

Captain Royland Gaetano (876B87)
Belter 5 terms Age 38 Cr60,000
Shotgun-1, Computer-1, Electronic-2, Jack-o-T-1, Navigation-1, Pilot-1, Navigation-1, Prospecting-1, Vacc Suit-1

Pilot Tal Anderson (7A4B86)
New Home Navy 4 terms Age 34 Cr3,000
Computer-1, Jack-o-T-1, Medical-1, Navigation-1, Pilot-3, Vacc Suit-1, Autopistol-2

Engineer Alia Kishhush (7B86C6)
Imperial Navy Age 34 4 Terms Cr 11,000
Cutlass-1, Engineering-2, Mechanical-2, Forward Observer-1, Laser Rifle-1, Gunnery-1

Gunner Valeen Eshemii (737695)
Merchant Age 34 4 Terms Cr 15,000
Shotgun-2, Auto-rifle-1, Gunnery-3, Mechanical-1, Vacc Suit-1, Steward-1, Trader-1

Details of the Hippity-Hop To It

The Hippity-Hop To It has been extensively modified over the years. The most extreme modifications have occurred on the X-boat Hop to It, mostly for increased living space and comfort. The data banks on the bridge deck and the living deck have been replaced with staterooms, the pilot’s on the bridge deck and the Captain’s on the living deck. The common area on the living deck has been rebuilt using fairly luxurious components, and the second airlock has been converted into additional space for the ships’ locker. It mounts a dual beam laser turret in place of the standard beam/missile/sand mix.

The Hippity service hull has been used in a variety of ways in the past. At one point, the ring between pods two and three was sectioned off for use as a fuel tank. Currently, that area is used to store various fittings to easily convert areas to other functions besides cargo; these fittings, including a full set of mining manipulator arms, takes up 10 dtons of cargo space. The staterooms in pod three have been removed, and the entire pod set up as a secure hold. The stateroom on the main deck in pod two is retained, but the upper deck stateroom has been converted into a cozy crew lounge. Occasionally, if one of the crew feels the need to get away while in jumpspace, they will come aboard the Hippity and stay in the guest stateroom.

Should the Hippity-Hop To It be encounter problems (pirates, hijackers, etc), those individuals would be well advised that the crew tends to err on the side of paranoia, and most nooks and crannies tend to have a minimum of two weapons tucked away in them. One attempted hijacking in the Islands during a passenger run resulted in a 20 minute firefight and 3 perpetrators being spaced.

All plans and images below were created by the author of the article, Donovan Lambertus.

Click on each of the small images below to see a larger version of the image


The Hippity-Hop To It mated pair The unmated Hippity landed.  The mated pair cannot be landed. Deck plans for the Hippity in its present configuration Deck Plans for the Hop To It in its present configuration Deck Plans for the Lab variant of the Vagrant Deck Plans for the Miner variant of the Vagrant Deck Plans for the Transport variant of the Vagrant