Ok, I understand the question. If the space ship counts as a wonder and you don't have enough time left I'm assuming, then you a city on a crappy wonder like Effle Tower and build that with the 'freights' at that point then switch it.
Shields in a Production Box (PB) building a Wonder are not cut by 50% if you switch to Space Ship (SS) parts. This allows you to IPRB SS parts, if you have obsoleted (or otherwise still have available to build when making a SS) 200 or 300 shield wonders, like Oracle or Lighthouse. For instance, with gold and a 20-shield city, you can buy a Barracks (empty PB) for 160 gold (40 shields * 2 gold/shield * 2 for empty PB city improvement = 160 gold), then switch to Oracle (losing 20 shields), then buying Oracle ( [300-20]*4*1 = 1120 gold ), then switch to SS Module (which takes 320 shields to build), then letting your city that produces 20+ net shields complete the task, since you now have 300 shields in the PB (at a cost of 160+1120=1280 gold). The 20 shields the the IPRB saves are worth 20*4=80 gold. And 80 gold is 80 gold.
Alternatively, you can do the same thing, but use Freight/Caravans to "contribute" to building the wonder. Each F/C is "worth" 200 gold (50 shields * 4 gold/shield). Ordinarily, you would have to
disband the F/C, which would give you only 25 shields, if you were constructing the SS part directly.
If you use a F/C to seed an empty PB (let's say you want to build an entire SS in a single turn), then you need only start with a Wonder (any wonder), "build" the wonder with the freight (you get the full 50 shilds that way), then switch to the SS.
For instance, a city making 10 shields can build a Component in 1 turn at no gold cost, if you have 3 F/C. Simply start a wonder... any wonder (PB is assumed to be empty), send in 3 F/C (now the wonder has 150 shields in it), and then switch to SS Component. Congratulations, you have 150 shields of work done, from those 3 F/C, and now your meager 10 shield (net) output city completes a mighty SS Component in one turn.
BTW, this method is important in doing most OCCs (One-City Challenges), and probably essential if you take a "size 4" or "size 1" OCC challenge.
So this thread was quite interesting, if someone discovered that an improvement (the Palace) could be used in lieu of a Wonder. A palace is obviously worth 100 shields, and this would be very useful in saving Gold in IPRBing SS parts.
But this method does
not work for Palaces, since the game treats the Palace as an improvement, and you lose 50% of your shields when switching (on all levels except the easiest, and obviously scenarios designed for it)... and you cannot give 50 shields from a F/C to the Palace PB (since the Palace is not viewed as a Wonder by the game!).
