Pat "Stonewall" Cleburne wrote:Historically, fleet's very rarely reduced forts on their own did they? I can't really think of any situation where that happened.
Forts Hatteras and Fort Clark
http://en.wikipedia.org/wiki/Battle_of_Hatteras_Inlet_Batteries
Fort Pulaski
http://en.wikipedia.org/wiki/Fort_Pulaski
In the first case, neither Hatteras nor Clark were proper forts and both were severely undermanned; in the second, significant damage was done by shore batteries on nearby Tybee Island- but those batteries were largely there because of the naval bombardment.
That said, most historians consider both examples of naval fleets bombarding forts into surrender, thanks largely in part to the James Rifled Cannon. Physical damage alone may not have been enough, but the psychological toll of taking fire without being able to return it, (with a similar effect, I believe, that flanking fire had on regiments), the exhaustion of ammunition, and the interdiction of reinforcements and supplies all forced combined to force the garrisons to surrender.
On the other hand you have examples such as Fort Fisher and Fort Sumter which, despite repeated efforts to bombard both into submission, held out nearly the entire war. Due to geography and supporting fortifications, the Union naval advantages were smaller or non-existence in these cases.
The current system works fine, but to accurately simulate history I have always felt that forts, especially coastal forts, need a little gradiation in terms of how "tough" they were; some forts were simply harder nuts to crack than others.
Something for a modder or a ACWII programmer to explore.