Jump Distance

[madhopper50]

Trying to get into Traveller and have a basic question. If "J1" ship moves one parsec and one hex in a subsector is one parsec, therefore a "J1" ship can only move one hex? Then somewhere I read about J1 & J2 Trade routes which allows for more than 1 hex jump?

[sjard]

Jump drives are rated as J1 to J6. The number indicates how far they can travel in parsecs per jump. They can jump less than that, but it still takes the same amount of time and fuel.

Most ships have fairly low rated jump drives, the higher numbers being both newer and more expensive. (varies by era etc.)

So a J1 route (also called a Main) are made up of star systems that are only one parsec apart in a string. A J2 route is no more than 2 parsecs between star systems. There can be systems that are only one parsec apart along a J2 route.

[madhopper50]

Originally Posted by sjard

Jump drives are rated as J1 to J6. The number indicates how far they can travel in parsecs per jump. They can jump less than that, but it still takes the same amount of time and fuel.

Most ships have fairly low rated jump drives, the higher numbers being both newer and more expensive. (varies by era etc.)

So a J1 route (also called a Main) are made up of star systems that are only one parsec apart in a string. A J2 route is no more than 2 parsecs between star systems. There can be systems that are only one parsec apart along a J2 route.

Thanks! So a J1 ship must carry enough fuel to jump to a star system greater than one parsec.

[Fred Brackin]

Originally Posted by madhopper50

Thanks! So a J1 ship must carry enough fuel to jump to a star system greater than one parsec.

A J1 ship _can_ carry fuel for multiple jumps at the usual speed of 1 parsec per week. Relatively few do. It's not an efficient use of the money invested in that ship.

[sjard]

Originally Posted by madhopper50

Thanks! So a J1 ship must carry enough fuel to jump to a star system greater than one parsec.

The only ways a J1 ship can travel to a system more than one parsec away are to:
A) Make one parsec jumps to systems in between, refueling at each system along the way (each system can only be one parsec apart with this method), or:
B) to mount extra fuel tanks (at the cost of cargo space), make a 1 parsec jump, refuel from that tank, and then make another 1 parsec jump to the destination. It is rarely viable to do this unless you have a lot of cargo space you don't mind wasting in this way.

Also keep in mind that no matter what the jump rating of your drive, it always takes roughly 1 week per jump. It doesn't matter if you have a J1 drive and only jump 2 AU within a system or the 1 parsec maximum that drive can jump. If you have a J6 drive, it still takes roughly one week to jump 6 parsecs, or one parsec, or anywhere in between.

So it can, long term, be far more viable to get a ship with J2.

So if you mount extra tanks in place of cargo, and you make 2 J1 jumps (most ships won't have enough cargo space for much more than one extra jump), it will take you roughly two weeks plus time to transfer fuel from the spare tanks to the main tanks.

[madhopper50]

Thanks for all the input. So basically a J1 ship isn't worth the bother if you can afford a J2 or better ship.

[sjard]

Originally Posted by madhopper50

Thanks for all the input. So basically a J1 ship isn't worth the bother if you can afford a J2 or better ship.

It really depends on where you are. If using the Third Imperium setting, especially the Spinward Marches sector, there is a fairly large Main that lets a J1 ship travel (one parsec at a time) to... well... Here's what the Traveller wiki has to say about it.

Originally Posted by Traveller Wiki

The Spinward Main is an astrographic group of systems in the Spinward Marches Sector, each within jump-1 of another.

Together, this grouping forms a corridor of jump points that allows simple jump-1 ships to travel to fifteen of the sixteen subsectors within the Spinward Marches, and to 236 of the sector's 439 known worlds.

So in a setting like that, aside from it taking years to visit every system on that main, there are more than enough worlds to visit for a very long campaign.

A ship with a J2 drive would let you bypass more places, and visit almost every other world in the sector (there are a small number that would require J3 to get to). It would also let you get to worlds on opposite sides of the sector considerably faster than a J1 drive could, even if it's accessible by the J1 Main (J2 could let you skip across areas where the J1 would have to travel for many weeks to get to the same point, effectively taking a J2 shortcut)