A can't believe they would go soblatantly wrong with land units becoming water units that they make water tiles behave like land tiles - this is nonsense.
I believe that to swap to water from land you need sg. to make it happen, again:
- a dock / port / seashore city tile
- some movement cost to make the change
landing is a different story, this would and could depend on lots of things,
but generally a unit should be able to land weherever it wants, again:
- you need certain movement cost, maybe start the turn next to land to make it.
- you may be able to land but not attack on the land in the same turn
these are just ideas...
but I am sure they test theirs at Firaxis...
I believe that to swap to water from land you need sg. to make it happen, again:
- a dock / port / seashore city tile
- some movement cost to make the change
landing is a different story, this would and could depend on lots of things,
but generally a unit should be able to land weherever it wants, again:
- you need certain movement cost, maybe start the turn next to land to make it.
- you may be able to land but not attack on the land in the same turn
these are just ideas...
but I am sure they test theirs at Firaxis...