Originally posted by RobO
Unfortunately, once you get Magnetism (or is it Navigaton?) all ships can cross oceans with impunity 
Even canoes
Here's a slightly crazy idea..why not eliminate the Navigation and Astronomy bonuses? I don't mean delete the Technologies from the game..but disable the 'everyone can cross seas' and 'everyone can cross oceans' features. Instead, canoes/galleys/triremes can only traverse coasts, all ships developed after Astronomy (except the Longboat, of course) can traverse oceans, and all ships developed after Navigation (except the Ironclad) can traverse seas.
There are two advantages I see in doing this:
...........1) It forces players to have to upgrade their ships in order to traverse more dangerous waters, as in real life...no more seeing the AI in the Modern Age sending its brilliant military force in a canoe

...........2) This enables later ships, i.e. the Ironclad, to effectively have the 'sink in oceans' attribute, without having it be cancelled out by the 'everyone can cross oceans' bonus found in Navigation.
(Ok, maybe we can let everyship cross Seas with Navigation, but certainly don't let everyship cross Oceans with Navigation. I'm thinking we let everyship cross oceans
much later, maybe with the invention of Radar, or Sattelites?)
Originally posted by Kal-el
3) no horse units should be able to upgrade to the Humvee
Funny, in every version of Dyp I can remember, I've clicked through the 'Horseman [upgrades to] Knight [upgrades to] etc, etc...' upgrade chain, and it's always ended @ Humvee
Ironclads are currently set to sink in Ocean, they should probably be set to sink in Sea as well. If they are given this additional restriction I may be inclined to up their stats to 6/7/3. How does that sit with you.
Ehh..6/7/3 still doesn't seem fair to the Ironclad. IMHO, even though Ironclads were Iron-
plated wooden ships, it still made them much stronger on the defense (it is iron, after all), and slightly stronger offensively - iron ships can hold bigger guns better than wodden ships, b/c of the added stability of iron.
IMHO, except for transport capacity, speed (maybe even speed), and ocean-faring ability, Ironclads and Steam Frigates should have their current stats
switched
6B) Unfortunately it is not currently possible ot set improvements as prerequisites for units. Oh that it were so, the possiblities that would open up before us.
Hear me out Kal-el, for I have a plan
It
is possible to make a unit appear with the construction of a Wonder - think Manhattan Project. But what if we were to do that same sort of thing - with a
Small Wonder?
IMHO - upon the discovery of Steam Power, a new Small Wonder will be available. This SW can only be constructed in cities with a Shipyard, and access to Iron - let's call this SW 'Ironclad Development' for now. Upon completion of 'Ironclad Development', the Civ that built it can build Ironclads.
In exemplum: The Americans build 'Ironclad Development' first - now, only they can build Ironclads. Next, the English build 'Ironclad Development' - now only the English & Americans can build Ironclads - etc, etc.
Two last comments, concerning the world map:
1) Early Middle-age Europe was plagued with Barbarian Invasions - think the Huns & Avars, who both used Horse Archers. Why not make the Barbarian Rider upgrade to Horse Archer?
2) I admittedly haven't checked

- but can Eurasians cross into the Americas via the Aleutian Islands? there would have to be some Ocean, of course, but I could see them as an *alternate* way to get there.