And, once again, I want to promote my "Coastal Fortification"-idea.
Make them
a Great Admiral improvement:
- buildable at coastal tiles (adjacent to land only) anywhere on the map, but not inside other culture influence zones
-
converts a 2 hex range of
water tiles into your culture. (Though
no culture flipping of already acclaimed enemy borders.)
- casts a
ZoC of 2 hex against enemy ships. (= slows ships down like the Great Wall does on land.)
- can
attack ships within 2 hex range.
(- ships may heal additional 10 HP/turn if stationed inside. This is not really necessary, as the cultural influence zone itself already allows ships to heal.)
The idea behind this:
a) helps to defend coastal cities against raids
b) helps to defend naval trade routes against raids
c) may control straits (I love especially this aspect)
d) may be used as sea outpost far away from the own empire.
--
furthermore:
e) is very close to the Great General's ability but not exactly the same.
f) is longer lasting and not so out-of-time in early eras than mine fields.
g) While canals are an interesting and maybe needed addition to the game, I don't think they fit very well to Admirals. After all, canals are mainly used for civil purposes (trading!) and should be a wonder or even a standard (but very expensive) tile improvement.
---
Additionaly, after rading the thread, some more suggestions come into my mind:
- Fix (is it a fix? or does it work as intended? If so: change it!) the fortification bonus of canons in fortresses.
- Give canons in fortrsses +1 range. (Might be too much, though.)
This would increase the usefulness of forts, which I always felt as necessary. Maybe I don't understand to use them properly, but I never build them (at least in the workable city radius).
As some others pointed out, the best way to counter mobile units (the frigates) are other mobile units, not static fortifications. In the long run, they will always lose (as they should!) and I can not see an unbalance inhere.
But with the proposals above, it should be possible to build up a worthwhile coastal deffense to withstand at least against a middle sized fleet.