The story of how newborn America won its independence from England, the greatest superpower of the era, is wonderful. It's got a great underdog to root for, noble and lofty ideals, and a trio of corners for every hat. But for a tale about war, it could use a little something else.
A little something like tanks, which was something technically feasible at the time though never attempted. Here's how it would have worked.
The common wisdom is that tanks were developed after the rise of the automobile, first coming into widespread use in WWI, a good century and a half or so after the Revolutionary War. That's all well and good if you're going to limit yourself to the facts. Me, I'm sick of facts, what with all their annoying smugness and know-it-all attitudes. I'm more interested in the exciting, drunk, shirtless cousin of facts: Speculation.
See, the Revolutionary War is the first war in human history where tanks of some kind could have been employed. And by tanks I mean a motorized, self-propelled machine capable of carrying soldiers and at least one mounted weapon. I'm skipping the part about armor, for this. I believe, in this hypothetical scenario, that first tank would have been employed by the Americans, but designed and built by the French.
It's well known that the French helped the Colonies a great deal during the War for Independence, providing weaponry, diplomatic support, and actual soldiers. It's not too far off base to think that if France had a secret weapon like an early tank, they'd give it to the Americans to use against their rivals, the British. And they actually did have the basis for such a weapon, thanks to Nicholas-Josef Cugnot.
Cugnot built what is widely considered to be the first almost-usable automobile way back in 1769. A second one was even built in 1771. The Cugnot fardier à vapeur ("steam dray") was a clumsy 2.5 ton brute designed to tow artillery. It ran, at about 2.25 mph, but the extremely poor weight distribution (almost all the weight ahead of the front wheel) did cause the very first automobile accident, which must have been the most gradual of out-of-control understeering disasters. The steam vehicle ran into a wall, slowly and heavily, and in actual reality, that mostly spelled the end of Cugnot's development.
But, what if that wasn't? What if Cugnot hadn't given up that day when the steam dray knocked down part of the Arsenal wall? The vehicle was kept (being eventually donated to a muesum in 1800), so it could have been possible that, when the Americans came asking for help, Cugnot would have been able to revisit his experiments of five years earlier. What if Cugnot had taken the steam vehicle put in storage, made some minor mechanical tweaks, and mounted a small swivel cannon on the rear of the chassis?
Mounting the cannon at the rear would have made the vehicle heavier, but would have also helped even out the weight distribution, making the beast somewhat more controllable. A Cugnot steam tractor with a mounted cannon and two soldiers to operate it could have proved a remarkable, if not entirely effective, weapon. It would have essentially been a tank. Or at least a motorized gun platform, which I'm saying is close enough for the 1770s.
The gun itself would have been a type of cannon known as a "galloper". The galloper was a smaller type of cannon, around 3 pounds shot weight, as opposed to 6 pounds for a field cannon. The name suggests it would be rapidly whisked around by horse. Unfortunately, it rarely lived up to its name. For the tank, I think a 4 pound galloper-type cannon would have been used.
With so much of the work completed on Cugnot's vehicle, a team of French Army engineers could have likely had the tank ready to be shipped to the colonies by 1778 or 1779. It's unlikely the tank would have been armored in any way, aside from the protection afforded by the mounted cannonball and supply storage boxes. The pivot would be the tricky part, since that was the limiting factor on most swivel-mounted guns of the era. To make this work, the gun would be bronze over iron, for lighter weight at the expense of range, and the pivot itself would be kept very simple. Essentially, it would consist of an iron Y-shaped yoke mounted in a heavy iron socket.
So far so good. All the ingredients for a working tank in 1776 are here, and viable. So what would it have done, exactly?
Amazing things. Why, if the Americans had such a tank back then, we could have won the Revolutionary War–- wait a minute. Okay, the truth is, it probably wouldn't have made a bit of difference. With only one, its use would have been little more than a novelty. And even if the Colonials were really committed to making it work, its relatively small boiler meant it would have to stop every 15 minutes or so to build up steam. Not exactly ideal in a war.
What it may have been good at is psychological warfare. Provided it would be as big, noisy, scald-y and terrifying as I think it would be to soldiers who'd never really seen machines more advanced than a pair of tongs, it would have made a very strong impression on alarmed British soldiers. Even if it never hit anything and just lumbered around, it would be an indicator of the willingness of the Colonials to try anything, and suggest the might of the French backing them up.
With that in mind, what a Cugnot tank could have done is perhaps prevented the War of 1812, since the defeated British would have memories of the huge, steam-belching iron elephant roaming the battlefields, and would suspect the US had built more, and better ones from the French original.