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In My Traveller Universe Detail what parts of Traveller you do (or don't) use in your campaign.

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Old September 30th, 2017, 12:13 AM
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Default Re-imagining the Book-2 drives

•The Scout/Courier, Free Trader, and Subsidized Merchant benefit from a standardized hull. Typically these hulls are not new construction but, taking advantage of their ubiquity, are recycled from older ships that have been scrapped. Their hull cost therefore reflects the builder's cost to acquire the hull and remove its contents, less any scrap value for the contents.

•The TL9 Model A maneuver drive is a 3dT gravitic thruster producing 2025 metric tons thrust, sufficient to provide 1.01G to a typical 200 dT ship. Its chief advantage is low power consumption: it requires only 202.5 Mw power to deliver the needed thrust, which leaves power available for other needs (such as a laser). Its chief disadvantage over the traditional maneuver drives is that, as a thrust-based propulsion drive, it sets an upper limit on ship mass: the 200 dT free trader is limited to a maximum 1000 metric tons of cargo - less on heavier worlds, more on lighter worlds - in order to maintain 1G, or it can only travel from orbit to orbit while moving at reduced acceleration.

(Maximum load is world-dependent:
•A: 600 t, a=1.25g •5: 2200 t, a=0.625g
•9: 778 t, a=1.125g •4: 3000 t, a=0.5g
•8: 1000 t, a=1g •3: 4333 t, a=0.375g
•7: 1286 t, a=0.875g •2: 7000 t, a=0.25g
•6: 1667 t, a=0.75g •1: 15,000 t, a=0.125g

A further disadvantage is that performance falls as the thruster moves farther from a gravitational source, dropping to half thrust at 10 diameters, reducing the free trader to 1/2g when fully loaded. For scout/couriers, the drive provides 2g within 10 diameters of a world and 1g beyond that. This is not a concern in a freight ship on a well-patrolled route, but it makes the unit impractical for warships and problematic for a civilian ship that finds itself under attack.

(Coincidentally, a grav-based maneuver drive costs about the same as a Book-2 Model A maneuver drive. I had to borrow some volume from the power plant to make it work. For High Guard purposes, the Model A maneuver drive draws 1 EP and produces agility 2 in a 100 dT scout/courier or an unloaded 200 dT free trader, or agility 1 in a fully loaded 200 dT free trader, when within 10 diameters of a world. The ship has half agility beyond, rounded down. For Book-2/Traveller-Book purposes, a ship at 1/2g makes a vector change every other turn: the player must wait one turn after making a change before another can be made.)

Some captains have been known to turn a disadvantage into an advantage by dumping cargo to improve acceleration when under attack: the free trader can double its speed when fully unloaded. A rapid cargo dump is accomplished by cutting cargo ties, shutting down the gravity field in the cargo bay, opening the bay doors, then applying thrust to move the ship on a vector opposite the cargo doors. This "sea cucumber" defense may also distract a piratical attacker. Scout/couriers do not carry enough cargo to meaningfully execute a "sea cucumber" defense, though dumping the contents of the small cargo bay or jettisoning the air/raft might persuade an attacker to stop for loot rather than continue exchanging shots, especially if the dump limits the attacker's window for retrieving loot by placing the contents on a vector to impact with a nearby planet or other body.

•The TL9 Model A power plant is a 2dT frontier variant power plant that produces 500 Mw at 1/3 the size and less than half the cost of a standard TL 9 power plant. Its chief disadvantage is low efficiency: it requires 5 times as much fuel to produce that level of power. It is more cost-effective than TL9-12 standard plants, the loss of cargo space being more than compensated by the decreased cost, but the added fuel requirements make it impractical for warship construction, where space rather than cost is a priority.

(Again, I borrowed some of the power plant space to make the maneuver drive work.)

•Because of the liabilities of the Model A maneuver drive, the Model A power plant is designed to function also as an auxiliary propulsion unit. By passing additional hydrogen fuel through the plant, it acts as a fusion thruster to produce another 1000 metric tons thrust to compensate for the maneuver drive's loss of thrust or, in certain circumstances, to provide added boost: a scout/courier within 10 diameters of a world can achieve 3G thrust when using the fusion thruster, while an unloaded free trader can achieve 2G beyond 10 diameters and 3G within 10 diameters. The feature is only used for combat as it consumes fuel quickly: one ton of fuel will provide two turns of thrust. Thus, a scout/courier or free trader with 10 dTons of power plant fuel has 19 burns available during a combat (reserving 1/2 dTon for power, which will last about 3 days) before going into its jump fuel; after a jump,it would have 7.5 dTons fuel remaining, leaving 14 burns available.

A subsidized merchant's B plant/drive is a duplex drive: a pair of A plant/drives designed to work in coordination with each other. It consumes correspondingly more fuel, providing one turn thrust per ton of fuel burned. The merchant has 10 dTons for 9 burns available before jump and 5 dTons, for 4 burns, on emerging from jump after a week in jump space.

When the power plant is being used for fusion propulsion assist, no extra power is available for other weapons; virtually all power not used by the maneuver drive is diverted to the thruster.

The fusion thruster should never be used near a planet's surface or in a planetary atmosphere. Doing so may result in seizure of the ship and arrest of its crew.

(For High Guard purposes, the Model A fusion thruster draws 1 EP when using a burn to provide thrust and produces an additional +1 agility in a 100 dT scout/courier or an unloaded 200 dT free trader, or +1/2 agility in a fully loaded 200 dT free trader. For Book-2/Traveller-Book purposes, a ship making a burn may increase its vector change by 1 for a 100 dT scout/courier or an unloaded 200 dT free trader, by 1/2 for a fully loaded 200 dT free trader.)

•The Model A drive/plant assembly can be arrayed in sequence to serve the needs of larger vessels. Fuel consumption increases accordingly. The Subsidized Merchant and Far Trader, for example, use a duplex unit. The 400 dT Merchant's 50 dT tank provides Jump-1 and 2 weeks' flight, while the 200 dT Trader's 50 dT tank provides Jump-2 and 2 weeks' flight, adequate for freight transport.

•Fusion Drives As Weapons: An advantage of fusion propulsion assist is that the ship may use its fusion thruster as a weapon when at short range, provided the drive is operational and fuel is available. When used, the ship attacks as with an energy weapon with a factor equal to its rating: an A is factor 1, a B is factor 2. The attack may be against another ship or craft, or the ship may use the drive against one missile attack: the missile attack must roll to penetrate. The ship may make a fusion drive attack without using additional fuel, if the fusion thrust is not also being used to change vector (or High Guard agility) during a turn: the ship makes a brief burn lasting only a few seconds, long enough for an attack but using minimal fuel. For the same reason, the power plant continues to deliver power for other uses.

The Model A drive/plant assembly is slightly more cost-effective than standard TL13 power plants, though the savings is not as significant; the deficiencies of the design lead most buyers to prefer standard TL13 technology from that point forward. TL15 standard power plants are more cost-effective than the Model A, being both less expensive and more efficient, and shipbuilding has been evolving toward a TL15 standard over the past 100 years, so the Model A is seldom seen in the Imperium except on low-tech worlds building ships under Imperial programs.
Comments made are for the purpose of offering alternative campaign settings for consideration. The writer acknowledges that Traveller is intended to emulate certain common science fiction tropes and that, in the course of emulating those tropes and providing a better playing experience, some liberties must be taken with science. No statement by the writer should be interpreted as constituting a criticism of the game on that basis ... except for that bit about Virus. Dude, really?!
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