Plumbata

[Robert Vermaat]

Admittedly, I have never thrown a plumbata, but I've thrown plenty of rocks of different shapes and they seem to hold true to their initial trajectory pretty well, even without a vaned guidance device being attached. I can imagine a poorly cast dart tending to veer left or right (slice vs hook if you are a golfer) due to the effect of centrifugal force, but at the distances these are meant to be thrown I wonder if that force would have enough flight time to significantly counteract the initial thrust of the throw. Arrows may be quite a bit more accurate, but they were fired in volleys en masse as well. I don't think the en masse delivery necessarily speaks to the accuracy of an object. Slingers were known to be extraordinarily accurate - but they 'slung' in groups too.

Rocks (or sticks) do not behave like a plumbata, not even javelins do. The thing with the weight is that the missile tail wants to overtake the point while in flight, and the flights prohibit that, straightening the missile out about halfway in the air. I’m no expert on ballistics, but my guess would that, especially concerning the longer distances, accuracy suffers from just that. Arrows are very much more accurate.
We agree on en masse fire – accuracy is less of a necessity.

OH throws are less susceptible to wind than UH because the higher arc of the plumbata in an UH throw means less forward momentum to counteract the wind's effect. At the peak of the arc the plumbatae reach their slowest speed and are highly susceptible to outside influence.

Indeed. But OH throws do not get you the same distance. And a flat tracectory is not what you need if you want a constant rate of fire over the heads of your comrades fighting in front of you, while a high trajectory can avoid the scuta held in front of your enemy, instead targeting them from above at a 45-degree angle.

Another factor is that UH throws lose accuracy the more forceful the throw. I played a version of baseball where the pitcher was required to deliver (lob) the ball to a 6 foot diameter plate 45 feet away... and the ball had to reach a minimum height of 20 feet. No maximum height was imposed, so literally the sky was the limit. It would have been to the pitcher's advantage to throw a very high ball, but no one could because they wouldn't be able to hit the plate consistently. So if I am in the back ranks of a formation in contact with the enemy I am only tossing my plumbatae about 30 feet or so high because that's about the limit of my accuracy. Don't need sharp, heavy objects falling on my brothers in the front ranks. But at a distance it is easy to OH throw a high arcing shot -perhaps not as high as the UH toss, but with much more forward momentum.

Well, if you’re in the back of a formation you won’t be able to see much of the enemy, so accuracy is not playing much of a role. Not being able to throw straight at their faces in an (almost) flat trajectory, makes you want to get as much of an impact, which is achieved by an arc as high as possible, delivering an impact with as much force as possible. We had plumbatae piecing an oak table of at least a centimeter from about 10 meters height. No need to achieve such heights as with your basketball (which behaves very different anyway – see above).

I question the preferred impact at a high angle assumption as well. Missiles dropping straight down on my troops are much easier to defend against than those same missiles coming in at, say, 45 degrees. How do you defend against that with your smaller shield if you are a barbarian? Consider; to the thrower, a plumbata in an enemy's foot or leg is almost as good as one in the head. Aside from the defense issue, some posters in this thread have noticed that angled strikes frequently result in broken shafts. I believe that to be a feature in that denies the darts' use to the enemy.

Well – the assumption is not 90 degrees, but 45. That’s the impact angle of my tests (and others) anyway.
The ‘broken shaft construction’ assumption is not one that I share. The weapon being constructed cheap and dirty is reason enough for shafts to break. I mean – the missile used by far the most on a battlefield is the arrow, yet nobody ever contemplates any design feature to make this missile unusable to the enemy (both sides often collected arrows to shoot back). For the relatively low number of plaumbatae lying around, I don’t think that seems to have been a tactical problem in the minds of the Romans either.

Underhand (UH) is easier for throwing because of how humans are built. And it is easier because we cannot develop the power, and consequently suffer the stress, that is developed by throwing overhand (OH). Frankly, I question the methodology of those who find superior distance UH vs. OH. Not to denigrate anyone! My experience in introducing American ballsports to Europeans is that the Europeans have real problems with proper form and mechanics in making OH throws. There just isn't the knowledge base in Europe on how to correct throwing form issues. However, if you want a laugh, watch me try to play soccer.

What can I say? Methodology is theory, testing is practice. Testing over many years by many people with different types of plumbatae consistently results in higher distances UH than achieved OH.
Again, stones or balls are not behaving like plumbatae, so maybe other forces come into play?
I would love for tests to show that Americans achieve better plumbatae distances than Europeans because of the way they’re trained in sports btw – that would be a nice study for someone’s phd! But in the meantime, I’ll stick to test results!
Soccer? You mean football.

A question comes to mind - if UH throws are best for distance, why is it that no military known to me teaches the UH throw for hand grenades? Even the German Stielgranaten were thrown overhand. I did qualify "expert" in grenades while in the US Army, btw.

Because a hand grenade (even a Stielhandganate) behaves differently from a plumbata? And you don’t always have the room to throw them UH? (But now I’m repeating myself)

If I have a legion under my command I am sure going to try and find a way to get as many darts in the air as I can. IF the Romans delivered pilae en masse (if), then they could do the same with the plumbatae. I haven't bought into the back-lines-feed-the-front-lines discussion. I just don't see that working when the front lines are in contact. As for cavalry attacks and the like, with an OH throw it would indeed be possible for all ranks to engage. Try that UH and you have some real problems. Not even a quincunx-style formation is adequate because the back ranks would still have a friendly 3-5 meters directly in front of them. Too early a release, a slip from sweaty hands, and boom! your buddy Flavius Targetus is now involuntarily donating his equipment to his successor...if you catch my drift. See how brave you are by standing 3 meters in front of a compatriot who is trying to throw UH for distance to get the sense of what I am saying.

Of course the Romans would do the same, but pila and plumbatae were thrown on different occasions. Pila were used to break the enemy charge (and plumbatae could be used in the same fashion), but plumbatae were also used during battle (when the pila were already spent), in the same way as arrows and slingstones. Who, in the same way, were also shot at flat trajectories at close range but at high trajectories from the back when the formations had engaged in close combat. There is no ‘back-feeds-front’at that time, we agree there, because the front fights with spear and sword at that point. But that phase of battle is far longer than the initial ‘closing with the enemy’, meaning the UH high-arc fire of plumbatae is what it was probably designed for, not the flat-arc of the pilum.

And no, 3-5 m is adequate, because you are NOT targeting the enemy in front of Flavius Targetus, but the enemy a few ranks behind him. As I wrote earlier, the Roman army kept up a constant rate of fire during the engagement of both armies, not by targeting the enemy in front but rather those at the back. Not only would it thin out the enemy, but also damage his resolve (the one in the rear are the first to run off) and prohibit them to ‘keep up the pressure’ (this was a thing in late Roman formation fighting). The need to guard yourself from what come from above prohibits from engaging with what come from in front of you.