Ever heard of a cannononball .. ovoid?

[Jim McDougall]

I neglected to note that my suggestion on flawed casting was also suggested by Dmitry, and although not established as a conclusion here, seems to remain plausible.

On the dynamics involved in firing, I wanted to thank Krockew for the fantastic and beautifully explained examples of firing and characteristics of these various projectiles. Along with the excellent example shown by Chris of the deformed shot from the battlefield, this material really begins to have fascinating dimension, and its great to learn more about the history of these cannons and firing.

Good example on the expansion of the metal when heated Fernando, and point well taken about heat expansion....really have had to watch tire inflation in travelling through these desert areas in temps up to 120 degrees indexed!!

Actually the more I look at the example Fernando has posted, it seems perhaps it might reflect distortion that might result in forward force as from being fired while extremely hot (as previously suggested). I am wondering if spherical shot when fired would spin or turn, or would the forward force keep it relatively fixed? more physics I guess, but if it was relatively fixed, the material would distort and begin to trail, yes?

On Chris' example, found on a California battlefield, I'm not sure the distortion here would be from heated shot as I dont think they would have used that in ths case. From what I understand, the heated shot was intended for incendiary results, and these would not have been required in a frontier battle where no structures were in place. It would have been logistically improbable as well IMO, so this example must have resulted from other causes. Even an excessive charge in firing would have only created a momentary burst of heat without duration and not been able to distort the shot, I would think.

Yup, definitely a music lover Nando!!! everything from blues to rock to heavy metal (wonder why they never had a group named cannonballs? ....and yes, I do know who Cannonball Adderly was !! Hard not to, one of the greats.


All the best,
Jim

[M ELEY]

Sorry to come in late on this one with my .2 cents. Agreed it does resemble an iron cannon ball more than a mill ball. I bought what I thought was a cannonball a number of years ago, but under the grime, it proved to be a steel mill ball ( ).

I think this is a cannon ball, perhaps used as hotshot and deformed on impact. I have seen (hee hee) balls with flattened sides and bent/deformed bar-shot that struck hard structures.

Still another possibility is that this is a cannon ball made using the 'shot tower' method. I've included two sites explaining this innovative method of making cannon shot, and although one confesses that the balls produced were perfectly round, I beg to differ. Confederate cannon balls were often ovoid, had rough seams, were oblong, etc. In any case, a dropped shot could explain the deformity in times of desparation during war-time. I imagine it would still have fired poorly, though...

http://www.waymarking.com/waymarks/W...er_Columbus_OH

http://www.examiner.com/downtown-bal...pplied-physics

[Jim McDougall]

That is really fascinating information Mark!!! I had never heard of a shot tower, nor such a method of making shot and cannon balls. While you might come in late, you do so with a bang!!! great stuff!

Thanks for the links on the sites describing these towers too. It seems so odd to fabricate these with such an elaborate method...I always thought these were cast in molds, and it seems like dropping a blob of molten metal would produce all kinds of various shapes, like a rain or tear drop, who would have guessed this method would be effective. I cant get Galileo outa my head on this one
It seems odd in the note that the Baltimore tower was still producing shot until 1892, but although rifled guns had come in long before and were technically obsolete, I suppose the smoothbore cannon would have remained servicable ordnance as required and as on hand.

If a ball was indeed oblong or distorted in shape, how would that have effected its firing ? If the spherical shape maintained force and rotation to retain kinetic energy, would the distorted shape cause the shot to slow as discharged, and lessen its range or impact?

It really is fantastic to learn so much more on ballistics and artillery of these times, thank you guys for all this information, and please excuse my attempts at trying to describe my questions with the terminology which may or may not be correct, my exposure to physics and dynamics is limited at best!

All best regards,
Jim

[fernando]

Hi Mark, i'll be damned
I fully agree with Jim ... last but not least .
Hardly shot towers were implemented in Portugal: i am still trying to find out if hot shot was used here; not impossible, though.
Not wishing to go off topic, but something that fascinates me and which i have not been managing to spot where i have read it, is that the "pointed" bullet was idealized by Da Vinci in the XV-XVI century, although only implemented just the "other day".
The guy was simply unique.

[laEspadaAncha]

Originally Posted by Jim McDougall

If a ball was indeed oblong or distorted in shape, how would that have effected its firing ? If the spherical shape maintained force and rotation to retain kinetic energy, would the distorted shape cause the shot to slow as discharged, and lessen its range or impact?

Howdy Jim...

Given the limitations inherent to a smooth bore and the subsequent lack of rotational velocity (that would have otherwise been imparted by way of a rifled bore), I doubt small variations in (shot) shape would have much more than a nominal impact with regards to precision and accuracy - IMO such variation would likely have been taken into account in the application of artillery tactics at the time.

The "shot tower" method is new to me, and not only interesting but congruent with the deformation of my included example, which has a small and subtle (but noticeable) flat spot consistent with its bottom-biased distribution of mass. This has always given me the impression it either deformed upon impact (unlikely given it is doubtful it would reach a sufficiently high temperature to do so), or had been dropped before it had cooled sufficiently to harden to the point it would resist deformation, something I now realize is inherent to the "shot tower" manufacturing process.

[M ELEY]

The shot tower method was created in England at the end of the 18th century. The process was used in other countries, but quite popular here in the U.S. Jim, there's a shot tower in Virginia not far from me on the New River. It's a pretty cool site to see from the highway if you are ever passing this way, mate!

elEspadaAncha, your cannon balls could also be more primitively cast iron of the period. They resemble my Rev War American 2 pounders with their "off"- rounded shape.

Yes, Fernando, I definitely agree that hot shot is still in the running. I was unaware before I read this thread that it was ever used against anything but ships. I was going to suggest that a near-molten ball striking ocean water could deform this way, but I'm assuming we know for sure it was found buried on dry land? Likewise, IF it had been used against a ship, one could look for pick-marks to the hot shot where a naval crew would have been working double time with their spiked axes to dig it free from the decking and kick it over the side.( the only way to extinguish these monsters, as buckets of sea water were futile). Fascinating topic, folks.

[M ELEY]

A few other sites of interest. The first speaks of mill balls. The second shows a few oddly-shaped cannon balls-

http://angloboerwarmuseum.com/Boer12...nnonballs.html

http://www.goldiproductions.com/angl...cs_shells.html

[kronckew]

i've never heard of iron cannon shot being made in drop towers, the few references i've seen seem to be by people who assumed too much.

shot towers were for making lead spheres, from bird shot up to small arms sizes. the low melting point of lead and the surface tension of the metal does indeed form spheres, the tear-drop shape so popular in myth is just that, free falling rain drops are essentially spherical, tho easily deformed by external forces.

in a shot tower lead was poured into an appropriate sized sieve or array of funnels selected to provide the correct final diameter, the height of the tower was based on how long it took the lead to harden on the way down where it terminated in a tub of water for final cooling.

after cooling the lead shot was tested for roundness on a tilted table and any that failed returned to the melt. i would guess that large balls of lead intended for case shot and cannister may have lead to the assumption that cast iron could similarly make large cannon balls.

not so, the height of tower required for the higher temp. and larger sized cannon balls molten iron would have been beyond the capabilities of the period. dropping an 18 lb. blob of molten iron into a bath of water is not something i would attempt from any practical height. the 2in. oval grape shot mentioned in the ref. above may have been just small enough for a very high drop tower, but i'd expect a bit more variation.

anyway, one of a few quotes i found on line, it followed a post where drop tower made 'cannon balls' was mentioned:

Someone misled you. Shot (for shotguns) is made in freefall using a tower. And it basically does work the way you're thinking: it doesn't necessarily solidify all the way, but the outside does, and that's enough for it to retain its shape when it hits the water at the bottom of the tower.

Cannonballs were generally made out of cast iron. If you look at an authentic one that's in good shape, you can usually see the mold lines and sprue marks where it was poured. They were usually poured into sand molds that were then knocked away after they cooled.

Some very old cannon balls (prior to the 18th century at least) were cast bronze or cut stone rather than iron, but most people switched to iron as soon as they were able to because it's a harder, cheaper material than bronze, and easier to work with and more effective than stone. (Bronze remained as a material for the cannons themselves well into the 19th century, though, since it has greater tensile strength than cast iron and is less likely to shatter.)

Also, if you think about pouring large quantities of viscous liquid, you'd realize that "dropping" a cannonball wouldn't work... Forming spheres via freefall cooling is only practical (in normal Earth gravity) for rather small parts, where the surface area to mass ratio is low.

oddly enough, on a science forum discussing the making of tiny silicon balls for solar cells...

i've owned and fired muzzle loading small arms (pistols/rifled muskets) and cast my own projectiles.

in the pistols (.36 and .44 calibre) i used commercially made shot that was swaged from lead wire or cast, 000 buck (0.36" nominal) from drop towers can also normally be used as the loading process for revolvers usually will trim off any slight oversize, and the forcing cone in the barrel will swage the ball to fit the rifling. rifles would take a cloth patched ball which allowed for some variation in diameter.

the .58 cal rifled musket took a .58 calibre minie ball. one of the shot tower blurbs i read about an american civil war shot tower that mentioned it being used to make cannon balls also said it made minie balls. i tend to doubt that, having cast my own for years.

minie ball.

note the deep recess in the base, propellant gas pressure would expand the base, forcing the raised portion by the grooves into the rifling. this not only provided for the rotation, but provided a gas tight seal that allowed for more efficient use of the propellant, increasing range. they could be made a bit smaller than the bore, allowing more rapid reloading as opposed to previous round ball/patch combos that required more effort to seat the ball which was engaged in the rifling from top to bottom & thus not only had more friction, but got worse as each shot further fouled the barrel. soldiers were known to pee down the barrels of their rifles in battle to clear the fouling so they could reload.

[M ELEY]

Well...that shoots that theory down. I assumed that some of the info I had read was correct that cannon balls were made in this way (included in the tour guide's speal about a local tower I have visited). If the issue is height, some of these structures were massively tall while others weren't. In any case, back to possible hot shot, I guess.

Here's what wikipedia had to say and a list of shot towers around the world, many of them dating to the 1780's-

http://en.wikipedia.org/wiki/Shot_tower

[celtan]

This procedure was originated by the inmortal Leonardo DaVinci. The result was a predictable perfectly spherical form.

Best

M

[QUOTE=M ELEY]

Still another possibility is that this is a cannon ball made using the 'shot tower' method. I've included two sites explaining this innovative method of making cannon shot, and although one confesses that the balls produced were perfectly round, I beg to differ. .

www.waymarking.com/waymarks/WM5CD3_Fort_Hayes_Shot_Tower_Columbus_OH
/QUOTE]

[celtan]

Guys, I remember seeing as a child some large ovoid metal shapes lying around in Galicia's ports. I believed initially that they were old cannon balls. I was eventually told by a local sailor that in old times, these were used in sailing boats for balance, "to keep the keel down, and the sail up". Somehow, these ovoid metal bodies were either attached under the boat, or in the lowest internal part of the ship. IIRC, they might have been placed near the keelboard housing.

My two "pesetas".

Best

M

[kronckew]

Originally Posted by celtan

...

see my post no. 24, the writer of that blurb on fort hayes was incorrect in implying cannon round iron shot was made in the tower. they probably made lead balls for cannister and for shrapnel shells, but iron cannon balls, not possible. not enough height for them to cool & solidify before hitting the water, which was to cushion the fall, NOT to solidify the shot. possibly they made round cannon shot there, but if so it was by moulding.

note that the ref. to the baltimore tower specifically mentions the production of iron cannon shot there was by use of moulds.

note the reference link to other world wide shot towers near the top of that page, all of which more correctly only refer to lead shot.

additionally:

In 1783, William Watts of Bristol took out a patent for a process "for making small shot perfectly globular in form and without dimples, notches and imperfections which other shot hereto manufactured usually have on their surface". By pouring lead into a sieve, and letting it cool as it falls, the lead forms into a perfect sphere before falling into a water tank at the bottom.

however, pig iron was frequently used as ballast in wooden ships as you noted, and would have been in whatever convenient sized chunks it was originally cast into. it was stored in the lowest part of the ship to ensure the stability of the vessel by countering any heavy weights (like cannon) above the centre of gravity as well as the lateral pressure of the sails which might have blown it over. (the english 'mary rose' is a good example of what happens when you get it wrong). the captain might on occasion shift the ballast around to 'trim' the vessel to gain an extra knot speed or two, or to improve the stability. cannon balls were of course stowed at the lowest part of the ship and were thus part of the overall ballast.

one of the jobs we had aboard ship, which was there from time immemorial, was to ensure that anything brought on board was stored stably, ballast, fuel, water, food, machinery parts, people, cargo, etc. all have to be stored so as to keep the ship not only level fore and aft, and from one side to the other, but vertically to ensure the stability of the vessel. as a marine engineer, i was trained in not only designing ships, but calculating their stability and how to test that stability. for any who are interested, here is the 'simplified stability testing for small passenger vessels' as an example. the unsimplified version is of course more complex Linky to PDF

as a coast guard marine inspector in new orleans, i actually supervised and approved these kind of tests...

[M ELEY]

No, no, wait! What if the tower was...

Just kidding. I'm one to admit when I'm wrong. Lead shot was made, but I've heard of lead cannon balls in times of desparation. Perhaps with it's low cooling point, they could have been made as such? In any case, our ovoid subject here was not a shot tower ball.

Ballast I suppose seems possible, but I would think that there were much better uses for iron, even pig iron. (early blacksmiths even fashioned tomahawk heads from it). After all, the majority of ballast in the past had been stones, right?

Could this ovoid mass of iron have been used for anything else? A reserve of iron for cannon balls during seiges? As a giant paperweight! Just thinking aloud...

[celtan]

Well, we know that vimanas, and UFOs have been reported in several holy books, including the Bible. Works of art in medieval time often depict these drawn in the skies.

It well might be this is a projectile was to be used in a giant slingshot or trebuchet machine, against these pesky visitors?

: )

Originally Posted by M ELEY

No, no, wait! What if the tower was...



Could this ovoid mass of iron have been used for anything else? A reserve of iron for cannon balls during seiges? As a giant paperweight! Just thinking aloud...

[M ELEY]

I know this is a shell, but I'm wondering if this could fit the bill of a double shot for short range?? I've never heard of double shell, but apparently one did exist, so??? It is the right shape. The argument that an ovoid projectile was impractical seems moot judging from this existing projectile.

www.aeragon.com/o/am/index.html

[celtan]

Thank you very much for the explanation. Live to learn!

: )

Originally Posted by kronckew

see my post no. 24,

as a coast guard marine inspector in new orleans, i actually supervised and approved these kind of tests...