Manaco
If anything, turrets should have a smaller range than a warship's.
In the 1600's or whatever era, a warship could easily stay out of range and bomb coastal fortifications, turrets in this case. Turrets would have 1-2 range and could take out transports and other ships if turrets are not destroyed beforehand.
This would allow the defender more time to come up with a counterattack against the warships, and the attacker would need to protect their warships from the counterattack. It'll create a much bigger impact on naval warfare.
Thus, the same range would be applied on land, however there is no land unit with the same ability as a warship, so it's just storming a turret with enough units that the turret can't target them all. (Reasonable to say one turret can target once per Cycle, and is not overpowered in any sense) One could simply send two L9 infantry and push around the turret, one of them would get wounded but ultimately can still ignore the turret and advance on. However 5 turrets in a line would certainly make more of an impact and may encourage attackers to remove those turrets.
I disagree. There's no way warships would have a capacity to hold bigger cannons than their land counterparts. In fact, its probably more the opposite. If anything, the coast was probably more susceptible to getting hit since it's a stationary target where as the ship is moving blip in the horizon. If you miss the land you still get collateral damage, whereas if you miss a ship it means nothing.
I'm thinking ships should have a greater range. The whole idea of roughly 60miles per sector is flawed IMO. At least when you consider the way we actually move units and build bases.
Regarding turret ranges: If the diameter range of a turrett is smaller than the distance a unit can travel, land units will be able to essentailly stop short of their range on one turn, then run right past them on the next without getting fired upon. That wouldn't make sense. Unless of source you do it like air unit defenses that shoot one shot per volley (aka land unit icon?).