Powder charge for bombard

[zdc1775]

I can't think of a better place to post this so if it needs to be moved or deleted Mods do your thing.

While discussing the fall of Constantinople and the bombards of Mehmet the Conqueror in my History class on Wednesday the question was raised as to how much gunpowder would be required to launch the bombard's 1500lb cannonball the mile that historical text referenced. When the Professor was unable to answer this it made me curious. After several days of trying to find this information on Google I have been unsuccessful in finding an answer and decided to tap into the immense knowledge available here on this forum and ask for help.

While I know that no-one knows for certain how much gunpowder was used what is a reasonable estimate of the weight of the charge needed?

Also forgive any grammatical errors as I posted this from my tablet.

 

[4v50 Gary]

You stumped me. Remember powder back then wasn't as consistent as it is today.

BTW, I read elsewhere (The Siege of Skoorda (sp)) that the Muslims broke up their cannons into pieces transportable by wagon, horse, camel and recasted it in situ.

 

[OYE]

Siege of Shkodra 1478

About 2000 Albanian men and women withstood several direct attacks by the muslims (Ottomans) numbering
more than 100,000 (by most acounts) and may have been as great as 350,000 at the high point in the attacks.
The siege lasted more than 6 months and was unsuccessful militarily. The fortress was ceded to the Ottomans
in a peace treaty with Venice. The defenders were allowed to leave unharmed as a treaty provision. Up to that point anyone who surrendered to the muslims under favorable terms were beheaded, regardless. Same as now.

OYE

 

[vagunmonkey]

If I remember correctly prior to the mid 1700's the standard service charge for smoothbore cannons was 1/2 of the shot weight. After powder became more consistent it went to 1/3.

 

[zdc1775]

You stumped me. Remember powder back then wasn't as consistent as it is today.

BTW, I read elsewhere (The Siege of Skoorda (sp)) that the Muslims broke up their cannons into pieces transportable by wagon, horse, camel and recasted it in situ.

I had read that the powder wasn't as consistent then as it is now but thought that maybe someone had read an old pamphlet or book about artillery that just might have had a reference to charge v. projectile weight.

Sultan Mehmet's bombards were 27' long, weighted 40000 lbs, had a 30" bore with 8" thick barrel walls, were cast as two pieces that screwed together, and took a team of 200 men and 60 oxen to move.

If I remember correctly prior to the mid 1700's the standard service charge for smoothbore cannons was 1/2 of the shot weight. After powder became more consistent it went to 1/3.

This is what I was hoping for. If that ratio is correct then that would mean that the powder charge for those guns could be 750 lbs. That would be a tremendous amount of smoke, fire, and noise. Would definitely be terrifying.

 

[ofitg]

The Dardanelles Gun was a similar bombard (with a 25-inch bore) which was built in the 15th Century.
The Dardanelles Gun still exists today, on display in England.

According to this reference, the Dardanelles Gun used a 150 kg powder charge -

https://books.google.com/books?id=P...epage&q=Dardanelles Gun powder charge&f=false

EDIT - The numbers presented for the Daranelles Gun support Vangunmonkey's "rule of thumb" - the powder charge is about half the weight of the projectile.

However, I am puzzled by the "1500 pound" projectile weight claimed for the 30" bombard..... the 25" stone balls used in the Dardenelles Gun weigh 600 pounds. If you scaled the 25" stone ball up to 30", it wouldn't weigh much more than 1000 pounds......

Perhaps it depends upon the type of stone used?

 

[zdc1775]

The Dardanelles Gun was a similar bombard (with a 25-inch bore) which was built in the 15th Century.
The Dardanelles Gun still exists today, on display in England.

According to this reference, the Dardanelles Gun used a 150 kg powder charge -

https://books.google.com/books?id=P...epage&q=Dardanelles Gun powder charge&f=false

EDIT - The numbers presented for the Daranelles Gun support Vangunmonkey's "rule of thumb" - the powder charge is about half the weight of the projectile.

However, I am puzzled by the "1500 pound" projectile weight claimed for the 30" bombard..... the 25" stone balls used in the Dardenelles Gun weigh 600 pounds. If you scaled the 25" stone ball up to 30", it wouldn't weigh much more than 1000 pounds......

Perhaps it depends upon the type of stone used?

1500 pounds was the weight given in our the history book.

After doing a quick calculation of the volume and assuming that the stone was granite or limestone I get a weight of 1430 lbs for a 30" stone. A 25" granite stone would weigh 825 lbs. Granite weighs roughly 170 lbs per cubic foot but sandstone only weighs about 145 lbs per cubic foot. Maybe that is the difference.

Either way that is a very large boulder and more black-powder than most of us will shoot in our entire lives for a single shot with this cannon.

 

[ExMachina]

I'll add to the mix the fact that without elevation adjustment, a bombard was like a mortar in that the powder charged was varied to obtain the desired range. So there will never be a single answer to the question

 

[BaltimoreBoy]

"... powder back then wasn't as consistent as it is today. "

Is it a matter of consistency or is it a matter of type?

Wouldn't 1453 see us with 'meal powder' rather than corned powder?

 

[Nom de Forum]

Formulas would vary by percentages of the 3 ingredients. This alone would make the strength of the powder undeterminable today unless there is a record of what percentages the Ottomans were using. At that time I think the components would probably be mixed at the battle field rather than at an arsenal hundreds of miles away for reasons of safety and to reduce the chance of moisture accumulation.

Question: Do we have unimpeachable sources that the the Ottomans were firing from a mile away? Why would they need to be this far from the city walls since typical projectile weaponry both mechanical and chemical was limited to probably 1000yards at the very most and I suspect possibly less.

 

[Nom de Forum]

Siege of Shkodra 1478

About 2000 Albanian men and women withstood several direct attacks by the muslims (Ottomans) numbering
more than 100,000 (by most acounts) and may have been as great as 350,000 at the high point in the attacks.
The siege lasted more than 6 months and was unsuccessful militarily. The fortress was ceded to the Ottomans
in a peace treaty with Venice. The defenders were allowed to leave unharmed as a treaty provision. Up to that point anyone who surrendered to the muslims under favorable terms were beheaded, regardless. Same as now.

OYE

Here we go again with a statement that is historically incorrect in several significant ways that appears to be posted for no other reason than to denigrate a diverse cultural group. This is the second time in less than a week I have seen this type of attack on THR. Different person but same type of excrement being painted on the target with a broad brush.

To begin with Muslim and Ottoman are not synonyms. During the centuries of rising Islamic power before the decline of the Ottoman Empire beginning in the 18th century the Muslim cultures were far more tolerant of non-believers than the Christian powers they opposed. The armies of Muslim cultures do not have a history of beheading all enemies that surrendered.

 

[ExMachina]

To begin with Muslim and Ottoman are not synonyms. During the centuries of rising Islamic power before the decline of the Ottoman Empire beginning in the 18th century the Muslim cultures were far more tolerant of non-believers than the Christian powers they opposed. The armies of Muslim cultures do not have a history of beheading all enemies that surrendered.

Excellent points and (from what I know of Islamic history) absolutely true. Let's not also forget the the first "sack" of Constantinople was by the Catholic Christian crusaders on the 4th crusade!

 

[CANNONMAN]

There will never be enough blood to quench the thirst of religious righteousness. I digress. 30" + (X)BP = 1 mile? I seem to recall that Napoleon had a cannon commander who did extensive studies on cannon ballistics. Diminishing returns readily stopped commonly accepted principles. Such as the more powder used the further the projectile would travel. Soon it was discovered that regardless of amount of powder or other factors, he could only shoot a ball so far. The 150Kg seems correct. The ball mass also seems correct. The 1 mile? I'm am absolutely not a physicist, but this sure seems to walk like a duck. If it's true, I stand humbled and quite amazed.

 

[ExMachina]

Yeah. A mile sounds implausible and even the book linked above says after 500m the stones broke up. Guessing "a mile" was more likely a metaphor for "a long ways away"

 

[Nom de Forum]

I did a little reading on Black Powder manufacturing technology in the 15th century. Early I posted that the ingredients for the powder were probably mixed at the battle site. That may or may not be true as the technology of wet mixing to make powder balls for transport was existent in the 15th century. The load consistency and ability to efficiently ignite such a large powder charge was probably very poor. Something else to consider is what "mile" are they talking about? French, English, Roman, etc. "miles" are all different distances. That being said, just because we think it not possible does not mean it was impossible. There are things that were done in the past that we no longer know how to do or do as well with the same materials. I still wonder why they would need to fire from one mile or more away or want to since it creates a much larger siege perimeter to maintain.

 

[CANNONMAN]

Great cite and better insight. Thanks Nom de Forum