I'm listening to the Hamilton soundtrack and there are frequent references to fighting in 'the trench' - obviously it's not a historical source but it got me thinking what was the combat like? What I know of the period combat is the later Napoleonic War combat - formations of men firing at each other. What was the combat of the Revolutionary war like, did it involve trenches and how did it differ from Napoleonic combat?
In the Early Modern Period, sieges were more common and often more important than battles; controlling key positions on the map gave you a springboard for future campaigns, and denied certain regions to enemy armies. Fortresses on the key positions could provide shelter to a defeated army, store provisions, or delay the enemy for weeks.
Fortress design in this period was dominated by the trace italienne, or the star fort. Because every angle of approach against these fortresses was covered by overlapping fields of fire, they were very difficult to assault directly. The siege became the object of scientific study, and by the late 17th century, military engineers such as Vauban successfully systematized the investment and reduction of modern fortresses. Selecting a weak point in the defenses, the attacking general would construct a trench parallel to the general path of the fortress wall, and emplace batteries to suppress enemy defensive fire. From there, the army would construct saps -trenches that zig-zagged forward at angles the defenders' cannon couldn't shoot into. Once suitably close, another parallel trench would be constructed, more batteries emplaced, so they could now begin to actually damage the walls and bastions themselves. Enemy infantry manned the 'covered way', a permanent trench at the foot of the walls; sapping forward again, the attackers would use a third parallel as the jumping off point for an assault on the covered way.
The song in question is focused on the 'Battle' of Yorktown; it's better described as a relatively short siege, in which the British constructed a series of small, linked forts and bastions the Allies needed to methodically reduce and assault to force the British surrender. The siege proceeded in the proscribed style of the day, featuring parallels, saps, the whole shebang.
This remained the proscribed style of siege into the Napoleonic Wars, but strategic, operational, and tactical innovations resulted in wars of a very different character than those of the Age of Enlightment; whereas the 18th century was dominated by wars of position, the art of war in the age of Napoleon is better described, as by Jomini, as a system of marches by armies in relation to each other. Rather than territorial or positional objectives, the destruction of the enemy's main field army is the end, and rather than the systematic reduction of a static fortress, battle is the means. As a result, trenches and other labor/time intensive fortifications had less role to play in this more mobile strategy, which resulted in more open battles and less trench assaults.
Could I add a follow up? During the revolution how well stocked and provisioned were these fortifications? Did they have a ready supply? Or was the the army/garrison supposed to hold out with what they could carry or locally source?