• this level can be "STONE"bridged by settlers after the development of construction
  
• it takes 2 turns to build such a bridge
  
• when not bridged they are easy to cross and hard to defend, no defensebonus.
  
• stonebridges become a menace for moderntime traffic so they should be replaced by or be upgraded to at least "Steel"bridges, they can be used for railways!
  

• these rivers can be "STEEL"bridged only by engineers after the development of steel
  
• building takes 3 turns
  
• when not bridged they are hard to cross and easy to defend, defense 150%.
  

• these rivers can be "SUSPENSION"bridged only by engineers after the development of massproduction
  
• building 4 turns
  
• when not bridged they are hard to cross and easy to defend, defense 200%
  
• they are navigable by sails and caravels
  

• these waters can only be suspensionbridged or tunneled with sufficient financing, when finished you ought to see that your money-account is lower, say about 1200 pnt. The financing would also require the new to introduce "science" of "PUBLIC-PRIVATE JOINT-VENTURE FINANCING" which allows massive projects to be realized (somewhere after the development of spacerocketry).
  
• building 6 turns
  
• with sea straits, they can be build between two diagonal adjacent "coast"squares
  
• it should be possible to defend them with coastbatteries which are to be built by (military-?!)engineers only.
  

I haven't worked out which effect all these different kinds of rivers have on the movement of units, but it should have. I think it also should have an effect on where to built your cities. The building of a bridge in a citysquare (which isn't possible now) should have a major effect on the tradebalance of that square (50% ?!).

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But like I've said before, having bridges and mobile bride-building units would totally destroy the AI - which wouldn't even know where to build a bridge, and I think there would also be a lot of problems with pathfinding.

Yes, the idea of Woodmen Chief is roughly speaking the same as mine. There are though a few major differences.
1) I suggest we let go of the CIV-advance of Bridgebuilding.
2) As an action bridgebuilding, in the different stages of advancement I suggested, should be made subordinate to the development of the respective advances of: a) construction, if you can build an aquduct you can build a bridge (and so the romans did); b) steel and c) massproduction, and d) a new civ-advance (whether it is what I suggested or something else). It would practically mean that when you command a unit to bridge a part of a river which yet can't be bridged because you lack the ability to do so, the AI should report that it can't be done untill the development of a), b), c), or d) etc..

Evil Capitalist,
As far as I know the Romans never build a stonebridge in the midsection of the Rhine. They may have done so in Switzerland, but certainly not in Germany or the Netherlands. When they where on campaign their (engineering) troops used to build pontoonbridges, rather feeble construction which had little endurance.
That brings me to the point I got from the thread "Crossing etc.",
ENGINEERING TROOPS!!!
It would be really nice to have those.
They should be able to build a road in two adjacent squares or a bridge/fortress within one turn, comes in handy when your campaigning, doesn,t it ??!!
They should appear with the discovery of engineering, the Romans did have them !!!!. Later on in the game the possibiltu to build or train should be depending on the presence of a university or barracks (see my comment on the Westpoint wonder)
Their abilities should increase with the advancement of your civ, like the MULTI-STAGE ABILITY of bridgebuilding is depending on the the discovery of new advancements as I suggested above.
The lifespan of their efforts though shouldn't last to long. These (roads/bridges/fortresses etc.) should break down, diminish after a few turns (say about four to five turns, really a short term), and should be vanished completely after say 10 turns.
There should be four stages of deterioration:
100% (none) > 6 turns > normal movement rate/defensebonus
50% > 3 turns > 50% of normal bonus
25% > 1 turn > 25% of normal bonus
00% (gone) > after 15 turns > no movement rate/ defense bonus
If you would like to consolidate their works you should have to send in settlers or (civil) engineers right after them to do things all over, even though a bit quicker than normally, 50% ?!.

Gees, it's really great to be on the net and talk to other Civvers. There's really too much in my head to say in one time. As you might have noticed I had some time to think things over. I hope I'm not being to methodical and tedious.

Wow, Vrank Prins, your suggestion's extraordinarily detailed! But as you'll come to find here, we often these debates of:

good gameplay vs micromanagement
realism vs too complex
having a good idea vs whether the computer can cope

I think you're getting into the complex side of things, but heh, never know how it goes, they're watching us, your know...

quote: Hey Ultra - if there was a South Asia-Oceania Apolyton meeting, where would it be held, IYHO?

Easy, the centre of mass of "South Asia-Oceania" - probably somewhere not far off from the centre of Australia... but this belongs in OT.

An engineering unit would be nice. They could accomplish tasks that normal settlers couldn't, i.e. build aquaducts, build bridges, etc.