Hmm... but without the Jump-1 ships, then the Jump-3 ships are going to get lumbered with carrying all the stuff that does only need to go to the next world along a Main - and that is incredibly inefficient use of them.
I'm well aware of that. If you go back over my previous posts, you'll note that I made the same point myself. Trade between neighboring worlds one parsec apart will be carried on jump-1 ships. But ONLY that trade. Anything that has to go further than one parsec will go by ships with higher jump numbers.
Just to make myself clear: I'm not talking about small obsolescent second-hand tramp merchants (a.k.a. free traders) making a precarious living jumping from world to world, scrounging for cargo and passengers and jumping on with half-filled stateroom and holds, going bankrupt with depressing regularity. I'm talking about regularly scheduled ships owned by companies who bought them from new, confident that they'd be able to fill the holds often enough to make a profit.
Also, I don't see Jump 1 ships trying to make the same sorts of runs along the Mains as a Jump-3 ship can. A J-3 ship might be able to get from A to F in a single week, while a J-1 ship takes a couple of months to go the long way round, but a J-1 captain won't try to do that. At least if he has a brain he won't.
Instead he'll take cargo and passengers from A to B, then take on a new cargo and passengers to ship to C, then a new load for D... another load to E, and a final load for F.
I assume you mean another load to F, and a final load for G.
That way he makes money on each leg of the journey, and visits all those worlds, from B to E, that the J-3 ship ignored.
(Side note: The J3 ship didn't ignore D; it has to stopover there in order to get to G
).
Anyway, what you describe works until he gets to C. Then he'll find that there isn't any cargo from C to D to be had. One in every four Traveller worlds (10 in 36, actually) have less than 10,000 inhabitants. (Note: I don't know exactly how big a population it takes to generate enough freight and passengers to keep a ship in business, so I chose 10,000 as the dividing line. If you guys will accept the information in
GT:Far Trader as reasonable, I could do some number crunching).
Sure, there will be mini-mains where random chance (sorry, I meant the flow of history) have created a string of worlds all populous enough to support a ship. Regina is on one that runs from Knorbes to Phlume and Rech, a grand total of 12 systems. Just how many ships the trade generated by worlds like Dinom and Jenghe can support is another question.
IMTU, there is plenty of work for shorter Jump ships, since there are a lot of jobs that the J-3 boys would rather not take, because if the cargo only has to be taken a single parsec, they're no faster than a J-1, and have (relatively) less space for cargo and passengers. J-1 ships can turn a profit on a run which would see a J-3 ship losing money.
No argument there. What I've been saying is that those runs are mostly very short and localized. I'm sure there are lots and lots of 10,000 T jump-1 freighters jumping back and forth between Rhylanor and Porozlo. I'm just as sure that there are NO jump-1 ships going regularly between Regina and Rhylanor (or Regina and Efate, or Regina and Strouden, or Regina and Mora, etc.).
Another example: A company may employ a jump-1 ship going back and forth between Mora, Jokotre, and Fornice, but it won't employ it going into Deneb or further into the Marches, because Dojodo and Grille are almost as effective as barriers to commercial traffic as an empty hex is (Not quite, of course; at least you can get fuel in the systems).
Hans