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Old 01-26-2018, 09:56 AM   #1
Join Date: Aug 2004
Location: Buffalo, New York
Default Fleet jump rules and implications

Hello Folks,
While trying to organize certain material for use with Fantasy Grounds and a Traveller campaign, I stumbled across both an errata for STARSHIP OWNERS MANUAL and the original book in my library.

For those interested - Don McKinney had done yoeman's work on compiling errata for any of the Traveller System rules he could get his hands upon. Said errata documents for CT, MT, T4 and even T5 were kept/preserved and are available for download.

Google "consolidated megatraveller errata" or you can simply go to the far future enterprises web site and download the errata of your choice

In any event, one of the rules from DPG's (Digest Publishers Group) STARSHIP OWNER'S MANUAL gave rules for fleet jumps. In a roundabout fashion, due to a falling out between the Intellectual Property owner for DGP stuff and the Traveller IP owner Marc Miller, much of the DGP stuff was removed from canon.

Fleet jump rules however, indicated that a fleet could attempt to jump together if they coordinated their jump AND spent twice as long in the jump process AND were in constant communication. I won't go into the formula for determining time in jump or what have you. Suffice to state, the intent of the rule was to insure that all ships jumping together would arrive at the same time +/- 30 minutes or so (ie, within 1 hour of each other). The problem in my reading of that rule - was that it permitted one to know the time span spent in jump space to within 167 hours plus a randomly rolled value that added between .2 to 1.2 hours transit time.

THAT rule, means that if someone wanted to enter into jump space after spending twice the time initiating the jump, they too should be able to arrive at their destination within 167.2 hours to 168.2 hours. Yet, if that were possible, the whole mess of "how long is a jump" could be avoided.

So, my suggestion for GURPS TRAVELLER?

All ships about to engage in a co-ordinated fleet jump, need to have one computer running the jump program, with as many copies of the program running as are ships jumping together. Call this the "Master Ship". All ships that try to coordinate their jump, get told when and how to jump (like a jump tape) but occurs in real time. Engineers only, roll for their ship to join the co-ordinated jump, such that if they succeed, their ship joins in the jump. If they fail, their ship is subject to the normal arrival issues of an uncoordinated jump.

Those ships that jump successfully together? Will arrive within 2d6-7 x 1/5 of an hour of the Master ship.

Thus, the master ship rolls for time spent in jump space normally. All other ships arrive between 1 hour early to 1 hour later than the master ship

For example, you have two DD's three Escorts, and a Light Cruiser all trying to jump together. The navigator plots his course, the pilot makes his skill roll to approach the jump point vector, and the Light Cruiser's Engineer makes his roll to enter jump space properly. Light Cruiser enters jump space. The engineer of the one DD fails to meet the demands for the energy curve, and his ship automatically is subject to the normal time in jump space rules. The second DD succeeds, and rolling 2d6-7, I get a -2 (having rolled a 5). This means that the DD arrives earlier than the Light Cruiser by -2/5 x 60 minutes or 24 minutes early. The three escorts all make their engineering rolls, and arrive as follows: ES1 rolling 2d6-7 and a roll of a 7, means it arrives at the same time as the Light Cruiser. ES2 gets a roll of a 12 which becomes a modified +5. It arrives a full 5/5 hours late (or 60 minutes). ES3, rolls an 8 - modified to 1, and will arrive 1/5 of an hour late, or arrive 12 minutes after the Light Cruiser exits into normal space.

This may also be a GOOD reason to enter and exit Jump space with a relative zero velocity. If your ship arrives in normal space 60 minutes late, if the ships had a vector of movement that would have caused them to move at say, 10,000 miles per turn - the late ship will be a full three turns behind in movement relative to the fleet's positioning prior to entering jump space a week back.


All ships engaging in a linked fleet jump (where a battle fleet or a convoy) need to be able to communicate via a dedicated tactical data link (something that commercial ships normally don't run on their computers). They have to be in constant communication dedicated to coordinating their jump, have to take twice as long from start to finish (ie 80 minutes instead of 40), and roll the vs Engineer's skill to partake in the jump. If successful, the jump transit time is that of the master ship, with slaved ships arriving in (2d6-7)/5 hours of the master ship.
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