Consensus on these forums seems to be that of all the types of units in the game, naval units are the least useful, with naval UU's, UA's and SP's being among the least valued.
This runs contrary to history, where navies have been a decisive strategic element of the success or failure of campaigns from Xerxes's failed invasion of Greee, the Roman Civil war between Augustus and Antony, the failed Spanish invasion of England, the American Revolutionary War (the first one
), and very notably in both World Wars.
The root cause of this discrepancy between Civ V and Historical reality, I believe, is in the corresponding discrepancy between the historical value of waterway in trade and supply, and their representation in Civ V, which is mostly as a geographical barrier, and little else.
Im hoping to stimulate a discussion regarding means by which the value of navies to successful gameplay can be increased.
This runs contrary to history, where navies have been a decisive strategic element of the success or failure of campaigns from Xerxes's failed invasion of Greee, the Roman Civil war between Augustus and Antony, the failed Spanish invasion of England, the American Revolutionary War (the first one

The root cause of this discrepancy between Civ V and Historical reality, I believe, is in the corresponding discrepancy between the historical value of waterway in trade and supply, and their representation in Civ V, which is mostly as a geographical barrier, and little else.
Im hoping to stimulate a discussion regarding means by which the value of navies to successful gameplay can be increased.