Aitor Alert! Manuballista found!

[Aluscladiusmaximus]

Since this is a wooden Manuballista I think it is safe to use the formula for wooden artillery. A frame 12" wide would be 6 spring diameters wide giving a 2" spring. This would make it more powerful than Aitor's or my Manuballista which have a 1.3" spring. In fact 2" spring is large enough for a small scorpion so did this one have a stand and a winch that hasn't been found

Aulus Claudius Maximus

[Lucius Aurelius Metellus]

So this machine is 12" wide with 2" washers? Is this correct?

[Aluscladiusmaximus]

28 cm is just about 12 inches and measuring off the drawing the spring size does appear to be 2 inches (5cm)

looking at the picture from the museum I would agree with Aitor that the stock is wrong. If it is a belly bow the curved bit should be horizontal not vertical as it is there to press down with your stomach when cocking the weapon. On Wilkins FerroBalista he turned the stomach rest vertical because he decided it needed a winch and a stand; He didn't know what to do with a part that didn't fit his theory but was listed in the manual.

The slide looks too thin to withstand the forces involved in cocking a belly bow. The slide is pressed against the ground when cocking.


Aluscladiusmaximus

[Lucius Aurelius Metellus]

Was there evidence of a winch mechanism found with this machine? If so, it was probably not intended to be a belly bow-type loader. What is the evidence for the "shoulder stock"? By that, I mean was there a shoulder stock found with it, or evidence that there had once been one? It sure is a tiny machine, but regardless, I bet it is still deadly. From some close -up photos I have seen of it, there seems to be some sort of brass or bronze "teeth" inside the slider groove in the "tiller". I am wondering if this was some type of ratchet/winch mechanism, similar to the iron ratchets/teeth seen on the outside of some other models of catapulta? This is just my guess, but despite its small size, it would seem (to me) that any engine that required being hauled back and cocked by means of a winch of whatever type, would need to be mounted to a stand in order to do so. What are your thoughts on this? Also, couldn't the shoulder stock as shown be just that...a shoulder stock? No, not one meant for countering recoil, just one that made aiming the machine more comfortable? Sometimes it can be a matter of "a rose by any other name is still a rose". These are just guesses on my part, of course, and I have no real idea of how this machine was actually built.

[Aluscladiusmaximus]

If this is a manubalista then it needs a curved stomach rest. If you don't have one when you try to cock a Belly bow the end of the case trys to make a square hole in your stomach. The curved rest spreads the force out. It requires quite a bit of force to cock a 1.3 inch manuballista so a 2 inch would be worse. The stomach rest is in line with the arms. If it was vertical like the reconstruction the arms would foul the ground and you could not use your hands to help pull the string back. It is worth remembering that a Manubalista is not cocked by pulling back on the string but by pushing on the back while the slider is pressed on the ground.
The shoulder stock is a red herring introduced by someone who didn't understand why firearms have shoulder stocks and had to explain away a curved bit of wood.
a shoulder stock does not work with segmentarta it doesn't fit under the shoulder plates and wont fit over them either.
It certainly is a lovely Little thing and would have been deadly otherwise they wouldn't have made it.

A belly bow still needs some way of locking the slide back so the teeth may well be part of that mechanism.

I have re read the German article and it quotes the dimensions as 28 by 21 cm. I hadn't noticed the 21cm bit. The front should be square 6 spring diameters wide and 6 spring diameters high. (The top and bottom of the frame should be 1 spring thick and the vertical struts 4 spring high). his probably means it is 21cm square and the extra 7 cm is the height of the washers. This gives a spring diameter of 21/6 =3.5cm or 1.4 inch. Without scale drawings it is difficult to be sure. Does anybody know where I can get some drawings or better pictures of it.

[aitor iriarte]

I'm afraid that we'll have to wait until the Xanten manuballista is published for that!
In any case, only the frame plating was recovered (as customarily, strange to say!) and the shoulder rest and inner ratchet only comes from the mind of Christian Miks, who reconstructed Pseudo-Heron's Cheiroballsitra exactly that way.
Incidentally, judging from the photos of the reconstruction, they could have inserted much more rope into the springs! :twisted:

Aitor

[Antonius Lucretius]

It's just a bet, or a wild guess, but I see this weapon as the equivalent of the 20mm cannon or the .50 machine gun mounted on contemporary small naval vessels like coast guard cutters, or in this case, fast roman patrol boats on the Rhine. The size is just right to be mounted on the foredeck of one of those galleys reconstructed in Germany (Mainz museum??).
My bet too is that there was a ratchet mechanism coming along with it, similar to the very famous "Cupid" gemstone.
That weapon maybe small, but I don't see it being carried around as an individual weapon. Seem to be a bit too heavy for me.
And naturally, the stock from that reconstruction shown was directly taken from a war surplus German 30mm FLAK cannon...
Recoil absorbing stocks came with the advent of firearms.
My third bet is that this thing was fired like a heavy machine gun, i.e. with two handles --or one, the other being on the trigger-- at the end.
Just a few bets...

[Lucius Aurelius Metellus]

Ave,
I agree, I would be willing to bet that not only was it NOT a belly bow, but also not fired from the shoulder in the hand-held mode, although it is small enough to do so. The theory that it could have been a type meant to be mounted on a naval vessel, or even on a wagon or something similar is an interesting one, and very plausible. I just find it hard to conceive that this was cocked like a belly bow, because as the gentleman pointed out in a previous post, it would seem that the slider was too small and fragile to withstand the pressure of being cocked in that manner. A weapon such as this (or any seige weapon for that matter) was probably pretty expensive to produce, so they would not have used it in a manner that could break it or otherwise damage it.
Like I said earlier, I am merely speculating on all of this, I guess we won't know some of these things for sure until it is published. :wink:

[Jeroen Pelgrom]

which, if i understood magister navis correctly, would take a year.

[Flavius Promotus]

Antonius Lucretius, The Xanten chairoballistra is probably 1st century AD, and the Mainz galleys are late Roman (late 4th to very early 5th century), so they can't have been in use together. But in general placing small artillery pieces on patrol ships was certainly common practice - so the Xanten chairoballistra could very well have been used both on land AND on the river. Tacitus mentions an attempt to mew down Batavian insurgents with ship based catapults - this attempt was thwarted by the Batavian oarsmen who took over control of the ships.

I have once discussed this with Aitor; if you shoot a bolt over the water at a very flat angle, it might 'jump' over the surface and hit a target very close to the waterline.
A test would be nice someday

We could provide a floating artillery platform (genuine mini-warship), who wants to test his manuballista on board ?

[Lucius Aurelius Metellus]

Well, if I could read the report on this machine when it is published, I'd be interested in building a working scale replica of it. Then we could test it out!

[Kevin J. Aschenmeier]

From the size of the machine, could we not call it a scorpio minor or Vitruvian 2 span machine?

As far as using artillery from a ship, do not forget Caesar, B.G. IV,25, 1 -2. Here Caesar orders his troops to drive the barbarians from the beach of Britian with a barrage of "..fundis, sagittis, tormentis..." The "tormentis" would be artillery amunition. So he was using ship-based artillery.

Kevin

[Vincula]

In an earlier post, someone refered to drawings, but I can only see two photos in my browser. Where are the drawings?
And who is magster navis? :?

[Praefectusclassis]

Magister Navis is one of our German boardmembers. Used to be online more, but is too busy in real life now (archaeologist, University of Cologne).

[D B Campbell]

From the size of the machine, could we not call it a scorpio minor or Vitruvian 2 span machine?

I apologise for resurrecting this thread so late in the day, but I have only just discovered RAT v.2! In my opinion, Kevin has hit the nail right on the head.

The machine discovered at Xanten in 2000 and exhibited recently at Köln is a catapulta, not a ballista. We can be certain that the Romans themselves would never have called it a manuballista, with the important rider that we don't know exactly what they would have called it.
There has been much speculation on what exactly constituted a scorpio in the time of Vitruvius (ultimately without conclusion), but the term seems apt for such a small arrow-shooter as this one. Whether it was hand-held or sat on a stand must remain a moot point.
Incidentally, ancient authors were rather keen on the blanket term tormenta ("torsion weapons"), which the German news sources sensibly adopted.

In advance of full publication, there is little that can be said in a technical vein.
For those not well-versed in ancient catapults, the defining component was the modiolus, conventionally translated as "washer" in English ("Spannbüchse" in German). In summary, every other component in a catapult was measured in multiples or fractions of the modiolus.
This is the crucial dimension because it dictates the diameter of the spring itself.

Thus, although all the print sources so far have quoted the dimensions of the spring-frame itself (the exhibition catalogue quotes 0.26m high x 0.22m wide, while press sources quoted 28cm x 21cm), the crucial dimension is the inner diameter of the modiolus, which (as far as I understand, from correspondence with Dr. Hans-Joachim Schalles of the Archäologischer Park/Regionalmuseum Xanten) averaged approximately 45mm.

For arrow-shooters, the machine was classified by the length of the arrow, which was calculated as 9 times the modiolus.
A modiolus of 45mm gives an arrow-length of 0.40m or (in Roman parlance) 1.8 spans. So, not far short of Kevin's 2-span catapult.

It's worth noting, first, that the spring-frame (from the dimensions quoted) appears to be "oversprung" -- that is, it's taller than it is wide, which has implications for the length of the torsion-springs. Vitruvius recommends that such a catapult should have shorter arms to counteract the effect of longer springs. (The only other known spring-frames, from Ampurias and Caminreal, are "undersprung" -- ironically, we don't have an ideal catapult, by Vitruvian standards.)

The second point to note is that the washers appear to be too large for the frame, judging by the reported dimensions. If the frame is more or less the right width, and was manufactured too tall (i.e., oversprung), the modiolus would have been around 35mm, giving an arrow-length of just over 1 Roman foot (0.3m).

Of course, all of this is speculation until the find is actually published.
It goes without saying that, if any RATers are directly involved in the project, their comments would be much appreciated.