Okay... I took another look at the save...and these are my thoughts...
Navy stuff, in general:
I don't recall the statistics for the Man-O-War in the unmodified game, but in this one we get A/D/M of 4/2/10, a bombard of 4, rate of fire 2. Our Galleons are slower and quite weak, with 1/2/8. Privateers appear to be worthless... as the movement rate is 5... though they
can bombard in this variant... with a rate of fire=0... what good is that?
Sizing up the East:
The Barbarians appear to have eight (8) coastal cities on the west side of their landmass. One is pop 6, two are pop 8, one pop 10, and the rest are pop12. Enemy naval bombardment has concentrated on Yaxchilan, with occasional hits on Chichen Itza and Palenque. Landings have occurred between Tikal and Liverpool.
It would appear that our best bet is to simply hold them at bay in the east. We have a harbor in Macchu Picchu, with a Market in the queue. Tikal is producing 2spt net, and has some mined BG that I swapped away from Tiwanaku. If we can get 2 productive shipyards going in these towns we can build our Eastern Squadron there. The harbor in the queue at Yaxchilan will give our Eastern Squadron a place to heal.
Sizing up the West:
The Barbarians have New Teoihuacan on a corner of their contintent. It's size 12, and has a harbor. There is another city further south that we can't completely see.
Bombardments have been regular at Zabalaam, occasional at Oxford, Akshak. Regular bombardments have also been noted at Agade (way up the western coast).
As Leif noted, Ivory is located on an island settled by Barbaria at Apache 2. It would appear that a modest task force could be launched from Zabalam to capture Ivory. Water tiles from Zabalam to Apache 2 are C-S-O-O-O-O-S-C. It appears that it would take 2 turns to reach that island.
We have 2 productive cities in London and Canterbury. London needs a harbor. Kish will complete its aqueduct in 4 turns, and has a harbor. Akshak is small and needs infrastructure... but it's got potential. Our western squadron should be built in London and Canterbury, and augmented by units built in Kish when it gets productive. Hopefully we can get a few Galleons built in Akshak. We need to get more workers into the peninsula.
Possible invasion locations:
As we've discussed, we could divide Barbaria by controlling the choke point. Chanca 2 is the Barbarian city on that choke point.
I propose we reconsider this plan, as the shortest sea-lane lies between Zabalaam and New Teoihuacan. If we can sack that city we can eliminate one of the 2 productive Barbarian cities on their east coast....and we'll have our toe-hold in Barbaria.
I think all this wierd Naval discussion risks taking our eye off one part of the ball: Civ warfare is primarily concerned with ground warfare. Naval warfare is nearly always a distant second consideration.
Other notes:
We could probably do a lot for our defensive position by waking up a bunch of our obsolete units and stationing them along all that rocky coast between Oxford and Isin. Now that I think about it...
we should make this a priority. It will be a lot easier to prevent barbarian landings this way than to pry them out of unimproved mountainous terrain.
Sumer will riot next turn. If that's prevented it should complete a Market, and become productive.
We need some Universities.
Theodora will offer WM+230g+42gpt for Physics. I propose we take the gpt off the table and sell her Physics for 234g. Use the lump sum gold to rush-finish our culture builds in Palenque and Bonampak. Hopefully she'll research Theory of Gravity for us... or at least lower the cost. We should probably save up the gold to buy her free IA tech. Of course...we've got saltpeter and horses to offer her in trade.
Edit: There is a fair amount of jungle and marsh near Isin. I set the workers to road first, and then they can join each other without wasting movement to do the wetlands clearing work.