Many people forget that the Traveller RPG is actually a generic system. In the years since the Little Black Books came out in 1977 the Third Imperium (3I) setting has come to define the Traveller RPG to the point that many believe that the Third Imperium is Traveller. Fortunately, Gypsy Knights Games’ Clement Sector setting breaks the 3I paradigm through a few simple changes. For a taste of the Clement Sector I strongly encourage you to download the free Introduction to the Clement Sector from DriveThruRPG to see the setting differences in the Clement Sector setting.
In the Clement Sector, the FTL system is the Zimm Drive. Instead of the standard Traveller Jump Drive that moves a ship across 1-6 parsecs of space in a week, the “Z-Drive” covers 1 AU in about 1.44 seconds, one light year in 26 hours, or 1 parsec in 84 hours (3.5 days). The Zimm Drive is limited to a practical range of 2 parsecs (actually 2.44) in 168 hours or 7 standard days. Ships greater than 5000 DTons cannot be equipped with the Z-Drive, and ships between 2000-4999 DTons have a risk of the bubble collapsing. The Z-Drive uses the same space and fuel requirements as a standard Jump-2 Drive in Mongoose Traveller (MgT).
This simple technology change actually has a great impact on adventuring in the Clement Sector. In MgT, to travel in-system a distance of 1 AU using a 1G acceleration drive will take 68 hours; at 6G the best one can do is 27.6 hours (MgT Pocket Rulebook p. 145). In the Clement Sector, a ship can fire up its Z-Drive and get there in 1.44 seconds. If one is trying to get to the outer system, in MgT at 6G it will take between 55-68 hours, whereas in the Clement Sector setting it take a mere 1.85 minutes. This forces changes in how one thinks about fuel, trade, and combat.
In the Clement Sector one can use their Z-Drive instead of Maneuver Drive to travel far distances within systems, but doing so requires a change in how to think about fuel consumption. In MgT, ships can jump less than 1 parsec, but it counts as a Jump-1 event for time and fuel (Pocket Rulebook, p. 141). Z-Drive performance in the Clement Sector can literally be “dialed” to the needed range. In my games, I added a fuel tracker for the Z-Drive which gives the ship 200 hours of “Z-Time” that can be used as appropriate. Need to get to that Gas Giant to top off the tanks? That’s going to cost you 2 minutes of gas!
The Z-Drive also changes the speed of intersystem trade. The quickest way to get around in-system is no longer a Maneuver-6 Drive, but a Z-Drive. Taken together with the Z-Drive size limits, bulk freighters are uneconomical; thus the need for smaller merchant ships is greater (i.e more adventuring opportunities).
The Z-Drive changes the nature of in-system combat compared to the usual Traveller approach. In the Clement Sector, a fleet could enter the outer system, refuel at the far gas giant, organize itself, and then “micro-jump” to the 100-diameter limit. The final approach micro-jump takes less than 2 minutes compared to several days in a standard Traveller setting. In the Clement Sector there is no need for a “long approach” battle. This has an impact on planetary defense forces which must stay within 100 diameters of the target they are protecting. In effect, non-Z-Drive become “static defense” forces whereas Z-Drive defenders become the “mobile” force.
In summary, the Zimm Drive in the Clement Sector from Gypsy Knights Games is both familiar to Traveller players and just different enough to make it interesting. The changes the Zimm Drive brings to travel, trade, and combat will require players (and GMs) to think about the setting differently – one can’t automatically fall back on the “3I way.” This is yet another reason the Clement Sector is so interesting a setting to play in.