October 5th, 2009 - Going Ballistic

Disclaimer: The last time I said, "There will be no math" on this blog... I lied. This time there will be math. Well, I didn't lie so much as I actually came up with a need for it.
Yes kiddies, get curious about things and you might have to go back and dust off your algebra and trigonometry. Who'd have thought there would actually be a use, much less a need for it...?!
Inherent to the scenario of ME doing the math, there 'could' be error. However, through the course of this discourse, (?) I have tried to keep things as accurate as humanly possible. In sparing you the dirge of endless hours spent in lab coats, scrawling formulae on chalkboards and feverishly scratching henlike on cocktail napkins in the wee hours of the morning, you'll have to take my word for a few things. Furthermore, to save myself that same dirge, I found websites that do the math for you!
That said, to wit (or to it, if you prefer):
Here is the exposition of the story, ala Cliff Notes version:

There is a cannon in front of the Veteran's Administration Hospital in south Minneapolis:







From the first moment I saw it, I have wondered to myself, "If I were to fire a cannonball from that cannon, where would it end up...?"


Namely because it points precariously in the general direction of our house...
Here are the finer points:

In order to figure this "brain itch" out, I had to figure out what kind of cannon this was, what it shot, what it's range was, and the angle at which it now points.
These seemingly simple questions opened up a world of interesting information. The internet is an amazing thing. Not only did I find out about this type of cannon, I found out about the last battle the ship that held this very cannon was involved in, where it came from, and with military precision, how to be a munitions officer aboard a ship from this period, how to maintain the cannon, load it, fire it, and take it out to breakfast.



It seems that there are a number of people out there with nothing better to do than to scan ancient documents containing the infinitesimal details about naval battles and weapons, and to them, my hat is off.
Why I can't find directions to my local BestBuy store online is beyond me.
The first thing I did was to go take pictures of it. I measured the inside diameter of the barrel with my fist and fingers and guessed at the size. I knew from my previous cannonball experience that cannonballs used to be measured in pounds, like a three-pounder, six-pounder, etc.
I thought from this maybe I could do some general web-searching about ordinance of this sort, take a guess about how far it could shoot and be done with it.
Looking down the barrel of said cannon, I saw that if it could indeed shoot something as far as across the street (Hiawatha Avenue, about 200 yds.(?), it may or may not end up hitting the blue house on the rise up from the railroad tracks. If it would hit the house, I'd have my answer, blog post done.
Moreover, what would the people that live in that house think?
More on this later...



However, and isn't there always a however, in trying to find out how far it could shoot, I had to figure out how heavy the thing it was supposed to shoot was, and how far it would normally go.
I soon realized I would need a more accurate calculation than using my fist and fingers.
I went back and measured it more precisely. I took more photographs.
It's interesting. When some guy is out in front of the VA with a tape-measure measuring the cannons, no one even bats an eye.
Or possibly they are afraid of walking up to the guy and saying, "Hey, whatcha' doin? Measuring the cannon...?"
They just go about their VA business. Okay, so some guy's measuring the cannon again, just don't make eye contact with him. Or maybe it's that they don't have to. Maybe the moment I crossed the perimeter they had already had me laser-scoped, RF tagged, triangulated, GPS'd, and fully coded in the government database.
Guy with camera and tape-measure... threat probability: low. Well, low to medium-low. However, if he comes back with a cannonball: terminate with extreme prejudice.
Sorry... deviated from the calculations there... anyway, before I went through all the gyrations of calculating the trajectories, etc.  I wanted a rough guesstimate of whether it could even hit the house. I accurately measured the inside diameter or "bore" of the weapon at 5.5 inches.



I found a website about calculating the mass of a cannonball, with a conversion chart and other interesting facts:
"English cannon, like others, were given names that indicated their sizes. The Falcon, Saker, Demi-culverin, Culverin, Demi-cannon, Cannon and Basilisc described calibers from 2-1/2" up to 8-3/4", and weapon weights from 800 lb up to 9000 lb."
Since my previous experience was with a 4 lb. / 3" cannonball, I was a bit surprised when thumbing down the chart showed me that a 5.5" barrel launched a 24 lb. iron cannonball to an approximate range of 460 yards point-blank (gun held level), to about 2650 yards (over 1.5 miles) when elevated by 10 degrees! This implied a muzzle velocity of at least 865 fps, or 590 mph (holy crap!)
A note about weaponry:
This is some pretty sick stuff when you think about it. These "machines of mass destruction" were designed to blow holes in things. Structures, ships, groups of human beings, horses, armor, whatever was in the way. They were the next logical step up from catapult weaponry which was used to launch all sorts of inhumane objects such as stones, shards of pottery, glass, metals, flaming and acidic objects, diseased livestock and human soldiers (yes, germ warfare back in the Roman times... here have some smallpox, my foe. Maybe it's like they say, it's easier to pull the trigger when you don't have to witness the results), as well as just about anything the operators could get their hands on to stick on the catapult and launch over or into the walls of fortresses.
Cannons, with their increased power, range, and velocity also got the creative destructive juices flowing in people that wanted to kill or deter other people, and besides launching balls made of stone, iron, or steel, launched such things as "grape shot" and fragmentation devices, some with "timers," that dispersed into many nasty pieces either at the muzzle or after landing, as well as "chain-shot" (usually two) cannonballs chained together that flew out at a high velocity, whipping around and around while flying through say, crowds of people. In no way am I intending to glorify these weapons. I think this some pretty horrible and sick stuff to do to fellow human beings. But I'm not going into the psychological rationale for warfare here, I'm just following through on my brain itch of what would happen if we could shoot a cannonball - from this particular cannon, um, "just for fun."
A couple of other notes about the history of cannons:
"The mass of the cannonball ranged from about 2.2 lbs. to about 728 lbs. depending on the era it came from and what it was used for. The cannon is said by some to be invented by a German monk, Berthold Schwarz, in the early 14th century. The earliest cannon was first fired using stones, and later progressed to metal balls. Beginning in the early 14th century, the shot was the heaviest (to destroy fortifications), and over the years the ball used became smaller and lighter (to provide better aim and shoot further distances). During our Civil War, the size of an average cannonball was about 12 lbs.
Also, according to the Americans at least, "almost all American Civil War cannon were muzzle loading; the breech-loading models, such as the British 12-pounder rifled Armstrong and Whitworth cannon, were generally "unreliable and awkward." Our cannon in question is a Spanish breech-loading model with a date of 1897 engraved in it's breech.



Another interesting measurement thing:
Shotgun barrels are quantified with a "gauge" measurement. You have to be careful with this nomenclature as lots of different things are measured in "gauges," usually cylindrical objects either hollow or solid. For example, if you were talking about the wire used in making jewelry, "20 gauge" wire would be 0.032" in diameter. With shotgun barrels, if you asked for a "20 gauge shotgun" the inside diameter of the barrel would be 0.615", quite a large difference. Somewhere along the line, "gauge" in reference to shotguns has come to mean: "the number of round lead spheres filling the exact diameter of a shotgun barrel that weigh one pound."
So if a shotgun barrel was found to hold 20 lead spheres that just fit in the diameter of the barrel and weighed one pound, it would be a 20-gauge shotgun. Simple, no?
This is why we rejected the metric system.
Also, you have to be careful with shotguns, and not for just the obvious reasons. Don't go sticking the end of the barrel into the mud then pull the trigger thinking the thing will just "clean itself out," like one of my junior high-school acquiescences did.
With no where to go, all that pressure built up from a rapidly discharging shotgun shell exploded the barrel and peeled it back like something out of an Elmer Fudd cartoon, causing "cuts about his hands and face," to put it mildly.
Okay, back to the puzzle.



Ours being a ship's cannon, I came across some interesting facts during my search to come up with a quick guesstimate of range.
Back in the 17th century, "most naval guns were made of iron, muzzle-loaded and the barrels were smooth bored (as opposed to "rifled," where grooves were cut down the barrel in a helical pattern to "spin" the projectile and keep it on a straighter course. This idea works and is still very much in use in the rifles of today, but it wasn't as successful with ball-shaped projectiles, due to their shape, small contact-surface and loss of muzzle-velocity.)
The cannon balls were made of solid iron.
The guns were measured by the size of the cannon balls. A "24-pound gun" fired cannon balls with a weight of 24 pounds. The caliber of a 24-pound gun was about 5.9 inches.
As mentioned earlier, I came across a college physics page that calculated the mass of a cannonball fitting in a 5.5" barrel as 24 lbs. Hence, I figured our gun was "a 24 pounder."
Artillery duels between naval enemies in the 17th and 18th centuries were normally fought at a distance of 170 to 1700 feet. The purpose of the bombardments was to break through the wooden hull of the enemy ship. At that time, to do that the ships needed to use the 18 or 24-pound guns.
A large ship of the line had a thickness of the hull at the waterline of about 2.7 feet, while up at the gunwale (the wall over the deck) the thickness was only about 1.5 feet.
In favorable conditions they could open fire at 2300 feet (about 1/2 mile). For the guns to be really effective, the ships needed to fire at a distance of 1700 feet or less. The best results were achieved at a distance of around 670 feet (200 m) or less; so close you could pretty much watch the 24 pounds of iron headed your way with much alacrity. As one source put it, "Naval warfare was extremely unpleasant for the sailor."
Sailors also found that if you fired the cannon ball parallel to the water's surface you could make the cannon ball "skip" or bounce and thereby achieve a longer shooting range. However, the penetrating power of the shot got weaker and weaker with every bounce. A 24-pound gun could effectively shoot a cannon ball about 1.25 miles using bouncing.
It was impossible for a cannon of this era to score a hit under the waterline. The cannon ball would bounce as soon it hit the surface. This made it more or less impossible to sink an enemy ship. You could destroy the rigging, the rudder and the upper decks and thereby make the enemy ship inoperative. If you could set fire to an enemy ship it could explode if the fire hit the gunpowder supply.
The firepower of a war ship depended on how many guns that could be fired at the same time at a broadside. The larger ships of the line normally carried between 25 and 40 guns per side. Frigates carried about 10 to 20 guns per side.
Our gun being from 1897, things had changed quite a bit by then. It was at this point in my research that I realized I had gone too far with the assumption that this particular weapon actually fired a cannonball.
I found numerous websites highlighting other towns in the United States that had been "awarded as trophies of war" other guns of the same type: from this very same ship,



the "Infanta Maria Teresa."

I realized with a thunk to my forehead that a 24 pound cannonball shooter would be pretty outdated for a naval vessel of this period.
Our gun is what was known as a "5.5-inch Hontoria (the manufacturer) gun" and it shot an armor-piercing shell that in total weighed 86 lbs., and at 25 degrees elevation had a range of 6.8 MILES. Wow, was I off.
Yes, it could hit the house, and something in downtown Minneapolis if pointed correctly.

This is what the gun looked like with all of it's armor attached:



Note the "ding" in the armor of this particular gun caused by an American 6 pound cannon. This is another Hontoria gun off of the same ship that carried ours.
This one sits in Ottumwa, Iowa. If you're really into it you can actually look at a chart of American "hits" on the Teresa.

This is what the back of her looked like with all the breech mechanism intact:



This one is from another Spanish ship that went down in the same battle, and is now on the campus of the U.S. Naval Academy in Annapolis, Maryland.

As mentioned above, the ship our gun was taken from was the "Infanta Maria Teresa," a Spanish steam-powered battleship (actually the flagship of their navy at the time) that was captured in The Battle of Santiago (Cuba) during the Spanish-American war in 1898. The destruction of this vessel and it's accompanying squadron annihilated Spain's last hope for successful pressure in Cuba or even for continuation of the war.
The fall of Santiago, which took place soon afterwards, was followed by negotiations for peace, and it might be said that when her sea power disappeared, Spain was ready to end the war.
Both the American "Minneapolis" and "St. Paul" ships played a large part in this battle, where in a nutshell; the Spanish Admiral Cervera was hemmed in to Cuba's Santigo harbor after re-coalling his three ships, and was pretty much trapped, out-gunned, fighting low tide, few provisions, and all-night searchlights that would have made escape nearly impossible.
The Spanish guns that were used in this battle were the (two) 11 inch main and (ten) 5.5 inch secondary Hontoria guns on the Teresa and on two similar vessels, verses the substantial number of 13 inch, 12 inch, and 3 inch guns on a plethora of American ships, the smaller of which could be used as "landing guns."
It came out in a communication from Admiral Cerveva found later that "out of the 3,000 rounds for our 5.5-inch Hontoria guns, only 620 are deemed reliable, the rest have been pronounced useless, and were not replaced by others for lack of stores when we left. Two of the 5.5-inch Hontoria guns of 'Vizcaya' and one of 'Oquendo' are defective, and had been ordered to be changed for others. The majority of fuses are not serviceable. We lack Bustamante torpedoes. The 'Colon' is without heavy armament. The 'Vizcaya' is badly fouled and has lost her speed. The 'Teresa' does not have landing guns, and of those that do, the 'Vizcaya' and one from the 'Oquendo' are unserviceable. We have little coal; provisions enough for the month of July. The blockading fleet is four times our superior; hence our sortie would positively be certain destruction."
The larger calibered armory on the American ships was less accurate, but to give an idea of it's destructive power, this quote comes from the highly detailed documentation of the battle: "In all, there were eight thirteen-inch guns in the pursuing (American) fleet, but when the engineers later examined the wrecks, it was discovered that only three hits by thirteen-inch shells had been made. The six twelve-inch guns succeeded in making two hits, but it was these two shells that practically caused the destruction of the "Infanta Maria Teresa" alone."
In many cases, if the shells hit steam lines or caused damage that created inordinate amounts if heat on the targeted vessel, the resultant heat and fires began to cause their weapons and/or munitions stores to explode and "the jig was up" as they say. Also, the Teresa was built using a lot of wood, something the American ships had since given up on because of the fire hazard involved.
The specifics as well as links about some of the other guns, parts, and the eventual fate of the Infanta Maria Teresa can be viewed here. Interestingly enough, her hulk was once raised for salvage only to be sunk again during a storm while being towed, and she was again, "lost at sea." She's actually a popular dive spot these days.




I couldn't pass up this pic of the ship's cat aboard the HMS Encounter in 1916. Ahh, tis a pirate's life for me.

So just when I thought I had this thing figured out, I had to go back to the lab coats and cocktail napkins, and totally recalculate. Here's where some of the error creeps in. My math sites tell me how far a cannonball travels, given a certain mass, angle, muzzle velocity, gun height, etc.  Now instead of a basically round ball, I have a "bullet-shaped" object. And "bullet-shaped" is a pretty broad term when you think about it. What is the angle of the 'cone' of the 'bullet'...? How much material is there behind the cone...? How much does this whole thing weigh...?
Gah. I found out that conical-shaped ordinance is measured in what is known as CRH or "caliber radius head", which basically tells you how pointy the bullet is. I'm not even going to tell you what the math looks like for calculating that, let's just say there are entire sites dedicated to trying to explain it.
As an aside, when someone decides to go shoot a cannon at something, there are artillery specialists that sit down with slide rules and thick glasses and say, after much scribbling and erasing, "point it like this, we think it's going to go here..."
But it doesn't always go there. There are too many constantly changing variables to really say, "it's going to go here."
I can't even imagine what it was like on a moving ship, shooting at another moving ship, it had to be more of a "feel" thing than a calculation.
In some of the documentation I came across about being a munitions officer in the 19th century, one book said (and I'm paraphrasing) "don't even shoot until your ship has a certain amount of speed built up, because the recoil of the guns could cause a dangerous pitch or yaw on your own vessel..." Pity the fledgling munitions officer that fires their cannon before the ship is ready and they have to steady the ship before they can fire another shot, especially by sail...  Maybe that's where the first human-cannonball came from.
In the early days, cannons were chained to the decks so they actually could move on their own from the recoil to negate some of the effects. Occasionally they had to be refastened and of course, repositioned.
And even in the era of the gun we are talking about, nothing was for certain; shells varied, powder varied, the barrel heated up, there were winds, humidity, and you were lucky if your gun didn't explode under it's own use.
Okay, so meanwhile our 5.5" Hontoria gun still sits on it's concrete block, fixed at a certain height and elevation. This should be easy, right?
Um, wrong. It was at this point that I realized my little hypothetical question was, er... a little too hypothetical.
After looking at shells and cartridges and munitions manuals for this stuff, I saw that at this point that the bullet-shaped head of the shell was actually powered by "charges", sometimes one or many more stacked on top of each other, or sticks of cordite bundled together that held the shell together without really even having a "case."
The thing is, the trigger-puller could vary the charge to tailor the load to approximate where they wanted it to go. Also, there were 'AP' or armor-piercing shells which had cold-hardened nose cones and were filled with powder that detonated on impact to break through the armor of the day. Consequently, they were heavier. There were also 'CP' or common-pointed shells that were not designed to strike armor, but were also filled with powder. They were lighter. The munitions manuals are filled with charts of what combinations of shell weights, elevations, angles, and charges are to be used to try and put the projectile in one spot.
I should have realized this earlier. Even with cannonballs, the cannoneer would vary the amount of powder and try to fine-tune the placement of their load.
So really without knowing what charges, shell, bric-a-brac and what-not, it doesn't make sense to try and calculate all the possible permutations of where the different loads might go.
However, I do know the gun could get a shell to the house with no problem, and at the angle it's set at I have no doubt it would go that far.
There still is the question of whether it would actually hit the blue house, from the way it's positioned now.
Interesting footnote (mid-note?) on that.
One day, after I had measured and photographed the cannon and was contemplating this story, my wife Sharon, our dog Happy, and I were walking near the VA.
Sharon wanted to do a more active "power-walk" and as usual I was dawdling and dragging my size 12's moping around, taking the occasional picture and "lookin' at stuff."
I decided to cross over Hiawatha Avenue and walk back "through the 'hood", and Shar and Hap would stretch it out and head out to 54th street and back.
As I walked along the sound barrier wall on the west side of Hiawatha and the 'LRT' (Light Rail Train) corridor, I had the thought that I should get my aging rump up that wall and take a look across to the VA and see if I could see the cannon from there, and verify if I could more correctly figure out where it was pointed.
Where I first climbed the wall, I realized I was too far north and had to backtrack up the street I had just come down. As I did, I started looking for "the blue house" and as I came up on it, I noticed a gentleman setting out a huge jar of sun tea, and having a smoke on his "over-the-garage" patio. It was attached to the "blue house."
I asked him if he could see the VA from there, and he said, "Yeah." I asked him if he could see it the cannon, he nodded and graciously beckoned me to "come on up."



From his deck, I could easily see his was the house basically lined up with the cannon in question. We got to talking, and it turns out he works at the VA for the Military Order of the Purple Heart, and his name is Mark. We talked about war stuff, I told him some of my dad's story, (he was a tail-gunner in a B-17, was shot down and held as a POW in Germany in WWII).
I told him that my dad had passed away some time ago and that it seemed like there really weren't very many WWII vets left. He mentioned that the last remaining Purple Heart vet in Minnesota was coming into the VA that week to claim his benefits, and he was 93 1/2 years old. Evidentially he had been discharged after the war, come through the VA hospital and gone right back to work on the farm - for over 65 years. Sounded like he was getting his full benefits due from the service.



I asked Mark what he thought of having a cannon pointed at his house and if he thought it would hit it if it was fired. He chuckled and said he didn't know, but he knew it was a gift to the VA from the naval department and that "there were a lot of stories in that building."
I asked if I could take some pics from his deck and try to get a semblance of whether it was pointed directly enough at the house to hit it or not. He was all for it, and was very encouraging to my cause. He gave me his card and said to send him some pics. I walked off feeling like I had connected a few dots in my story, and felt good for being able to talk to him about it.
From both sides of the cannon, it's really hard to tell "exactly" where it is pointed. To the best of my ability, from looking down the barrel, and looking at it from Mark's deck, and through amazing internet aerials, I can see it on Google Maps.
I plotted a line from the cannon image's barrel on Google Maps as closely as possible towards it's projected landing line, and to me it seems that it is pointed just a hair to the north of Mark's blue house.
With the relatively high power of this gun, I don't think there would be much error from windage or any other interference being as close as a couple hundred yards away. The shell is leaving the muzzle at around 1364.53 miles per hour. It's going to go in a pretty straight line for a while.



Here you can see the cannon on it's pedestal pointed just to the left of where we were standing. Just to the left of where we were standing is Mark's house. To me it looks as though it would bear even further left, but it would be close. It looks to be just a tad high of an angle to hit the house on a straight shot too.
It would be nice to have some better method of seeing the exact scoping point of the gun, such as a green laser that could be pointed out of the barrel in the dark, but we're just not that technologically advanced here (at least right now - if the opportunity arises, don't be too surprised if I'm over at the VA some night pointing a green laser at your house Mark.)
I'm going by my eyeball and compass and ruler on Google Earth. I think it will miss the house. Not by so much though that if it were my house, I'd say sure, go ahead and try it...
However, since I now had all my practical data in place, and I still wanted to know where my 'shot' would go, it seemed like it would be a let-down to bail out at this point.
I found a great chart of the Spanish ordinance of the time, which tells me the muzzle-velocity and maximum range of this gun for the two types of shells it normally shot.
I decided I would follow through and try and figure out where my load would end up in a "best case scenario" situation, using the muzzle-velocity, calculated angle, gun height, and maximum range given on the chart....

Being that I have been cranking away at this post for numerous weeks now, I am going to take a pause and take a deep breath, put my lab coat back on, sharpen my pencil, and say for the time being...

"To be continued..."

Keep your head down, Mark.

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