Danish cannons for 3D printing

[Waldemar]

 

Again, Swedish digitaltmuseum, and again I am not able to provide a link for this specific plate, which I did not written anywhere when downloading, sorry. It must come from the Armémuseum resources.

 

 

[Waldemar]

 

I also calculated the weight of this barrel for possible verification of its dimensions. Reading the engraved weight markings as ‘XVI S(keppund) : X L(ispund) : [...] Markpund’ gives a result of approximately 2250 kg.

 

Admittedly, this is a fairly typical weight for a legitimate 24-pound cannon, yet this particular specimen, as a ‘drake’, is a relatively light cannon, being short and with thin barrel walls, so the result seems quite reliable.

 

Now, if you make a 3D model of this cannon (or even without it), you can calculate its volume and multiply it by the specific weight of bronze, which for a copper to tin ratio of 10:1 should be, say, between 8.5 and 8.6 g/cm³. This is actually the least reliable component of the calculation, as the actual alloy may have had different proportions and also other components as well. But these calculations are not difficult and are always worth doing in similar reconstructions.

 

[thibaultron]

Determine the length using the drawn bore width as a meteric.

[Nirvana]

Once I have my Elegoo resin printer up and running, I will certainly try out printing some cannons.

[TJM]

@Waldemar, it seems the canon is actually a 42 pounder: it is also depicted in the Grunth collection:

 

 

 

It is extremely short, only 13 calibres. Even a 24 pounder at 17-20 calibres would be longer overall, like it's neighbors on the page above. 

 

But it seems the 42 pound designation on the Swedish drawing is actually the Danish poundage.

 

The search for a C4 36 pounder continues! 😅

 

Edited Tuesday at 06:09 AM by TJM

[Waldemar]

 

4 hours ago, TJM said:

@Waldemar, it seems the canon is actually a 42 pounder: it is also depicted in the Grunth collection:

 

No, please let me explain how Grunth converted a Danish 36-pounder cannon into a Danish 42-pounder cannon, or rather how he did not reconvert Swedish 42-pounder to the Danish 36-pounder.

 

First of all, Grunth's beautiful drawing is a redrawing of the barrel from the Swedish inventory drawing I showed earlier. However, Grunth completely lost track of his calculations because he took the Swedish barrel weight markings for the original Danish ones, and as a result, he also used Danish units of measurement instead of Swedish ones. And in general, he should have known, but did not know, that the weight of Danish barrels was not measured and marked in skeppund, lisfunt and pund, but just in pounds, then perhaps he would not have made his mistake.

 

The barrel is marked with the weight: 16 skeppund : 11 lispund (again: this is not the Danish way, but the Swedish way of measuring the weight of cannon barrels).

 

Correctly, according to Swedish units of measurement, this translates to:
16 x 136 kg + 11 x 6.8 kg = 2250 kg, or
16 x (400 markpund) + 11 x (20 markpund) = 6620 Swedish markpund

 

Incorrectly, according to Grunth:
16 x 160 kg + 11 x 8 kg = 2648 kg
16 x (320 Danish pounds) + 11 x (16 Danish pounds) = 5296 Danish pounds

 

In Denmark, skepppund and lispund were admittedly also used, but not in artillery to denote the weight of barrels.

 

Similarly, the calibre of 42 pounds written on the drawing was taken by Grunth directly without converting it to the Danish pound measure.

 

I believe that the same errors also apply to his other redrawings of Danish cannon barrels based on Swedish inventory drawings from 1670–1691.

 

 

[TJM]

I am not sure the logic holds. I agree that this is a possibility, but it relies on the assumption that Grunth copied the Swedish drawing. Do we know this is the case?

 

Grunth's drawing fits perfectly with a 42 pounder, from a bore size PoV. But of course that would be the case if the calibre is the only unit of measurement used to make the drawing. And he just assumed the 42 pounds was the Danish measurement.

 

Regarding the weight, I end up with close to 2500 kg based on the volume of a 3D modelled version. That is closer to Grunth's measurement for the weight, but somewhere in between your two calculations. 

 

I am not sure how to settle this definately.

Mind you, I am not saying you are not right here, I am just saying that I cannot prove it with the volume calculation.

[Waldemar]

 

2 hours ago, TJM said:

I am not sure the logic holds. I agree that this is a possibility, but it relies on the assumption that Grunth copied the Swedish drawing. Do we know this is the case?

 

On the first page of the 1860 edition, there is a note with the following content (but for some reason this note was omitted in the 1865 edition!):

 

In Danish:

 

Almindelig Bemærkning. Af de i denne Samling Tegninger optagne aeldre danske Metalkanoner existere ikkun de i Virkeligheden, ved hvilke saadant udtrykkelitgt er bemærket, uf de övrige haves der ikkun Tegninger, hvis Originaler findes i det kongelige svenske Krigsarchiv. Disse Originaltegninger, der skrive sig fra SIutningen af det 17de Aarhundrde, ere i Reg. Ien forsynede med Angivelser af Calibret, hvilke i det efterfölgende ere benytrede. De Angivelser af Godstykkelsen, Piecens Længde i Calibre og i Fodmaal samt Calibrets Störrelse udtrykt i Tommer og Linier, som nedenfor ere opförte, maae for de Piecers Vedkommende, hvoraf der kun haves Tegninger tilbage, kun betragtes som tilnærmelsesviis rigtige, idet de kun ere bestemte til at give er almindeligt Begreb om vedkommende Pieces Beskaffended.

English translation:

 

General remark. Of the older Danish metal cannons included in this collection of drawings, only those for which this is explicitly stated actually exist; for the rest, there are only drawings, the originals of which are found in the Royal Swedish War Archives. These original drawings, which date from the end of the 17th century, are provided with indications of calibre in the register, which are used in the following. The specifications of the thickness of the metal, the length of the pieces in calibres and in feet, and the size of the calibre expressed in inches and lines, as listed below, should be considered only approximate for those pieces for which only drawings remain, as they are only intended to give a general idea of the nature of the pieces in question.

 

Reproduction of the first page of the 1860 edition:

 

 

Nevertheless, for what I hope will be a final resolution, which I am also personally interested in, I will look for other drawings of captured Danish cannons in the Swedish artillery inventories from that period, and on which Grunth based his attractive drawings.

 

And there is still the possibility that I have been misled (again) by modern authors who, for the purposes of their publications, may have converted the weights of the earliest Danish cannon barrels into pounds, instead of leaving it in its original configuration or at least additionally referring to it.

 

 

[TJM]

40 minutes ago, Waldemar said:

 

 

On the first page of the 1860 edition, there is a note with the following content (but for some reason this note was omitted in the 1865 edition!):

 

In Danish:

 

Almindelig Bemærkning. Af de i denne Samling Tegninger optagne aeldre danske Metalkanoner existere ikkun de i Virkeligheden, ved hvilke saadant udtrykkelitgt er bemærket, uf de övrige haves der ikkun Tegninger, hvis Originaler findes i det kongelige svenske Krigsarchiv. Disse Originaltegninger, der skrive sig fra SIutningen af det 17de Aarhundrde, ere i Reg. Ien forsynede med Angivelser af Calibret, hvilke i det efterfölgende ere benytrede. De Angivelser af Godstykkelsen, Piecens Længde i Calibre og i Fodmaal samt Calibrets Störrelse udtrykt i Tommer og Linier, som nedenfor ere opförte, maae for de Piecers Vedkommende, hvoraf der kun haves Tegninger tilbage, kun betragtes som tilnærmelsesviis rigtige, idet de kun ere bestemte til at give er almindeligt Begreb om vedkommende Pieces Beskaffended.

English translation:

 

General remark. Of the older Danish metal cannons included in this collection of drawings, only those for which this is explicitly stated actually exist; for the rest, there are only drawings, the originals of which are found in the Royal Swedish War Archives. These original drawings, which date from the end of the 17th century, are provided with indications of calibre in the register, which are used in the following. The specifications of the thickness of the metal, the length of the pieces in calibres and in feet, and the size of the calibre expressed in inches and lines, as listed below, should be considered only approximate for those pieces for which only drawings remain, as they are only intended to give a general idea of the nature of the pieces in question.

 

Reproduction of the first page of the 1860 edition:

 

 

Nevertheless, for what I hope will be a final resolution, which I am also personally interested in, I will look for other drawings of captured Danish cannons in the Swedish artillery inventories from that period, and on which Grunth based his attractive drawings.

 

And there is still the possibility that I have been misled (again) by modern authors who, for the purposes of their publications, may have converted the weights of the earliest Danish cannon barrels into pounds, instead of leaving it in its original configuration or at least additionally referring to it.

 

 

Very nice information, thank you! 

 

This makes your theory quite plausible, I think!

 

 

[Waldemar]

 

Taking a closer look, I have found at least two dozen original drawings in the Swedish artillery inventory from 1670–1671 for the fortresses of Stralsund, Helsingborg, Malmö and Landskrona, on which Grunth based his redrawings. Here I show only some of the ‘duplicates’ I found.

 

Returning to the problem of determining the calibre of the cannons, and in particular the calibre of the Danish ‘42-pounder’ cannon: the original Swedish inventory includes cannons of various origins: Danish, Swedish, Imperial, from northern Germany, Russian and Polish-Lithuanian. All or almost all of them have their calibre marked on the Swedish drawings. However, it should be noted that these guns were not museum pieces at the time, but fully functional weapons currently in use. Therefore, the calibre of all these cannons must have been given in a uniform way, that is, in this case, according to Swedish units of measurement, and not according to the individual origin of these cannon barrels. And Grunth simply copied these calibres verbatim from the Swedish inventory without paying attention to this circumstance, i.e. without recalculating the values into Danish measurements.

 

Decide for yourself what you want to do with this information; I have just shown you the option available.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Edited Wednesday at 12:41 AM by Waldemar

[TJM]

Thank you for looking into all of the @Waldemar, it is really interesting. 

 

I am not sure what to make of it, and while what you say makes sense on it's own, there are some things that does not fit what we otherwise know:

 

We know that the most common shot weight for the larger warships of this time was 24 pounders - most common second battey armamament was 12 pounders with 6 or 4 pounders on the castles and/or cabins. We also know that some of the larger series of 'halv-kartover', 24 pounder, were 'De Nye Konger' (the New Kings) of 24 pounds shot weight (as oposed to the 'Gamle Konger' - Old Kings' from 1603-1607 which were 14 pounders) and the Apostles which were 12 pounders. Many of the 'Nye Konger' are in the collections, your second to last set above is a so called 'Løvekonge' - a lion-king - which are known to have been a Danish 24 pounder, but it is also labelled as a 24 pounder in the Swedish drawing! We see many cannon labeled as 24, 12, 6 and 4 pounders here which lead me to believe that these are the original Danish shot weights, not the Swedish ones. Otherwise, everyone from Grunth to modern experts like Barfod and Probst would have it wrong! If the poundage was Swedish, these would be strange Danish measurements of 20.5 pounders and 10 pounders, not calibres we find very often in the sources! 

 

I agree that it is strange that the Swedish drawings would quote the Danish weights, so there is mystery to be solved here, but if the measurements were Sweedish, I would have expected numbers like 28 pounders and 14 pounders to be prevalent, not 24 and 12, which look like the original Danish weights!

 

I am truly not an expert here, and I am just trying ro reconcile the sources I have, mainly N. Probst, "Christian d. 4.'s Flåde" and various writings of his in Marinehistorisk Tidsskrift.

 

Incidently, I actually made the 3D model of the aforementioned 'Løvekonge' 🙂 :

 

 

 

 

 

 

 

Meshy did a fine job of making assets from the Grunth drawings 🙂 

 

 

 

Edited Wednesday at 06:59 PM by TJM

[Beckmann]

Hi Thorbjørn, that looks so nice!! That would make a lovely cannon model. Are you planning to print it?

Where these cannon barrels from iron or bronce?

Matthias

Edited Wednesday at 09:44 PM by Beckmann

[Waldemar]

 

A beautiful 3D model. Finally, something visually appealing after all those austere cast iron guns from the 18th and 19th centuries .

 

 

As for the calibers of the Danish cannons, my intention is not to convince you of anything, but I am simply curious about how it was in the case of Danish artillery (as well as for other countries). I just thought you might also be interested. 

 

In addition to the archival sources themselves, my most important modern studies on technical aspects of Danish artillery are:

 

Michael H. Mortensen, Dansk artilleri indtil 1600, 1999
Otto Blom, Kristian den Fjerdes Artilleri, hans Tøihuse og Vaabenforraad, 1877
Egon Eriksen, Ole Louis Frantzen, Dansk artilleri i Napoleonstiden. Forudsætninger og udvikling 1760–1814, 1989

 

It seems to me that at least a partial explanation for this apparent anomaly concerning the guns' calibres is the peculiar duality of weight measurements in Danish artillery during this period, described in detail by Blom on pages 100–110 of his work. Here is just a brief summary of this issue by Blom himself (from page 110):

 

Det synes herefter , at man fra omtrent Aar 1600 har brugt den nürnbergske , efter 1687 saakaldte »gammelvægts « Kaliberstok til Bestemmelsen saavel af Kuglernes nominelle Vægt som af Kanonernes Kalibre » efter Talstokken udi Høiden «, men at man iøvrigt har brugt det kjøbenhavnske Pund, som fra 1613 var lovmæssigt for hele Riget, og som stemte overens med det 1698 nærmere lovbestemte danske Puna, til alle virkelige Veininger saavel af Kanoner som af Kugler, idet man vel kjendte , men til daglig Brug ikke ændsede Forskjellen mellem Støbejernskuglernes nominelle Vægt efter Talstokken og deres reelle Vægt i danske Pund. Den nürnbergske Vægt , af hvis Anvendelse der findes Spor , kan formodes blot at være brugt ved Tilvirkningen af Fyrværkersager , der vel som oftest foretoges efter tydske Recepter.

 

English translation: It appears that from around 1600, the Nuremberg weight, after 1687 known as the “old weight” caliber scale was used for determining both the nominal weight of the round shot and the caliber of the cannons ”according to the measuring scale in height”, but that otherwise the Copenhagen pound was used, which from 1613 was legal for the entire kingdom, and which corresponded to the Danish pound, which was more precisely defined by law in 1698, for all actual weighings of both cannons and cannonballs, as the difference between the nominal weight of cast iron round shot according to the measuring scale and its actual weight in Danish pounds was well known but not changed in everyday use. The Nuremberg weight, traces of whose use can be found, can be assumed to have been used only in the manufacture of fireworks, which was usually carried out according to German recipes.

 

 

Apart of that, I did find samples of Danish cannons with calibers of, for example, 14 pounds or 26 and 27 pounds (trekvart kartove) both directly in Swedish artillery inventories and in Thelott's album (via Mortensen's 1999 publication). Or, there are known examples of Danish 20-pound demi-cannons (halve kartover). However, I will not cite these examples, as I am not sure if you are really interested in these indeed rather complicated and niche issues, and quoting these graphics and comments requires quite a lot of effort .

 

 

[Waldemar]

 

@TJM,

 

I have a polite request for you. Let's assume that this Danish cannon, which according to the Swedish inventory is 42 pounds, would originally have been a 48-pound cannon in Denmark.

 

 

Please rescale this cannon barrel in your 3D program to a 48-pound caliber and recalculate its weight, assuming a bronze density of 8.6 g/cm3 or similar.

 

The result will be for comparison with the weight engraved on the barrel, which is 16 skeppund : 11 lispund, and which according to Danish measurement is 5296 pounds or 2648 kg.

 

This attempt, if successful, should finally remove my doubts on this matter and finally point to the correct solution to this problem.

 

 

[TJM]

22 hours ago, Beckmann said:

Hi Thorbjørn, that looks so nice!! That would make a lovely cannon model. Are you planning to print it?

Where these cannon barrels from iron or bronce?

Matthias

Hi Matthias,

 

At some point, I will definatly print this - likely also in 1/32 for a display model! I am deep into researching the artillery of Christian IV's time in preparation for a future project, but unlike the later artillery the measurements are all over the place, as the current conversation with Waldemar clearly shows! But I am slowly getting the hang of this and at least i can read the sources! 

 

All of these cannon depicted by Grunth are bronze. At the time, they called these 'metal' pieces as opposed to 'jern' (=iron) pieces. Ther heavy artillery at the time (the first half of the 17th century) were genrally bronze, Iron only really becomming prevalent in the late 17th century and only took over completely by the 1750's or so. 

[TJM]

22 hours ago, Waldemar said:

 

A beautiful 3D model. Finally, something visually appealing after all those austere cast iron guns from the 18th and 19th centuries .

 

 

As for the calibers of the Danish cannons, my intention is not to convince you of anything, but I am simply curious about how it was in the case of Danish artillery (as well as for other countries). I just thought you might also be interested. 

 

In addition to the archival sources themselves, my most important modern studies on technical aspects of Danish artillery are:

 

Michael H. Mortensen, Dansk artilleri indtil 1600, 1999
Otto Blom, Kristian den Fjerdes Artilleri, hans Tøihuse og Vaabenforraad, 1877
Egon Eriksen, Ole Louis Frantzen, Dansk artilleri i Napoleonstiden. Forudsætninger og udvikling 1760–1814, 1989

 

It seems to me that at least a partial explanation for this apparent anomaly concerning the guns' calibres is the peculiar duality of weight measurements in Danish artillery during this period, described in detail by Blom on pages 100–110 of his work. Here is just a brief summary of this issue by Blom himself (from page 110):

 

Det synes herefter , at man fra omtrent Aar 1600 har brugt den nürnbergske , efter 1687 saakaldte »gammelvægts « Kaliberstok til Bestemmelsen saavel af Kuglernes nominelle Vægt som af Kanonernes Kalibre » efter Talstokken udi Høiden «, men at man iøvrigt har brugt det kjøbenhavnske Pund, som fra 1613 var lovmæssigt for hele Riget, og som stemte overens med det 1698 nærmere lovbestemte danske Puna, til alle virkelige Veininger saavel af Kanoner som af Kugler, idet man vel kjendte , men til daglig Brug ikke ændsede Forskjellen mellem Støbejernskuglernes nominelle Vægt efter Talstokken og deres reelle Vægt i danske Pund. Den nürnbergske Vægt , af hvis Anvendelse der findes Spor , kan formodes blot at være brugt ved Tilvirkningen af Fyrværkersager , der vel som oftest foretoges efter tydske Recepter.

 

English translation: It appears that from around 1600, the Nuremberg weight, after 1687 known as the “old weight” caliber scale was used for determining both the nominal weight of the round shot and the caliber of the cannons ”according to the measuring scale in height”, but that otherwise the Copenhagen pound was used, which from 1613 was legal for the entire kingdom, and which corresponded to the Danish pound, which was more precisely defined by law in 1698, for all actual weighings of both cannons and cannonballs, as the difference between the nominal weight of cast iron round shot according to the measuring scale and its actual weight in Danish pounds was well known but not changed in everyday use. The Nuremberg weight, traces of whose use can be found, can be assumed to have been used only in the manufacture of fireworks, which was usually carried out according to German recipes.

 

 

Apart of that, I did find samples of Danish cannons with calibers of, for example, 14 pounds or 26 and 27 pounds (trekvart kartove) both directly in Swedish artillery inventories and in Thelott's album (via Mortensen's 1999 publication). Or, there are known examples of Danish 20-pound demi-cannons (halve kartover). However, I will not cite these examples, as I am not sure if you are really interested in these indeed rather complicated and niche issues, and quoting these graphics and comments requires quite a lot of effort .

 

 

 

 

I truly appreciate this @Waldemar, thank you for taking the time to dig into this and help me out! 

 

I had not come across Otto Blom's book - for reference, it can be found here, all out of copyright and free to use or reproduce: https://www.kb.dk/e-mat/dod/11342801000A.pdf

 

I had not before seen the point about the Nüremberg pounds, which are the basis for the measurement of the guns bore and shot sizes. even if this is in Danish, it is 150 years old and hard to read due to the long and complicated sentences - much more like modern german i think - and because of the rather unstructured way the arguments are put forth - more like a strain of thoughs than a well planned text. 

 

I will try to give a brief recap of some of the most important points I have found:

 

The cannon's bore size and the shot size was based on a so called 'talstok' (number stick), showing the diameter of the various bore/shot sizes. However, this was based on the Nüremberg pound, not the Danish pound! The bore of the cannon were naturally larger than the shot diameter, to allow for some windage and Blom suggests that the nominal bore was rounded up to the nearest pund park on the 'talstok', where the shot size was rounded down. This meant that it was common to have a cannon with a 26 pound bore ("pund udi høiden" = pound in the height = the bore diameter) that fired a nominal 24 pound cannon ball. Now, to complictate things, the daily measurements of shot weights were done using the normal Copenhagen pound ( 1 pund = 0.498 g). Blom suggests that they clearly new the difference between the Nüremberg pound used for the bore and shot classification and the actual nominal shot weight in Danish pounds, but that it was simply not a difference that was taken into account in practice! 

 

The following is a nice little table showing the difference between bore, nominal shot weight and actual shot weight:

 

 

So, a 24 pounder (halv kartove) would have a 26 pound bore (5"8'0IV diameter) and fire a 22.44 Danish pound shot (on average!) with a diamter of 5"6'2IV. 

 

This difference between Nüremberg and Danish pounds can be seen from account lists where the nominal shots are listed, but the total is also weighed. A delivery in 1683 is quoted for a total of nominal 114440 pd, but weighed in at 99736 Danisg pund - a difference of almost 15%. 

 

Now, let's have a look at the common sizes - these are sorted by nominal bore sizes:

 

While there are many strange sizes, the eight from the previous table are by far the most predominant: 30, 26, 16, 12, 10, 8, 5, and 1, corresponding to nominal weighs of 27, 24, 14, 10, 8, 6, 4 and 1 pounds. The first two are the trekvart kartoves and halv kartoves respectively, though the kartove designation refers to the size and weight of the gun, not the shot weight, so there are quite som vararity within the kartove klasses - but by the 1630's and definately here at the end of Christian IV's reign, the 27 pound trekvart kartove and the 24 pound halv kartove was the common ones. 

 

With regards to the 42 pounder from the Swedish and Grunth drawings that we have discussed previously, this particular piece is mentioned specifically in the text:

 

This is described as a hel kartove with a Nüremberg shot weight of 42 pounds, and likely a bore caliber of 45-48 pounds. Here, Blom mentions that the Swedish drawing is presumably using the Nüremberg measurment as well, which might seem surprising! But he mentions in other places that this system was also used in Sweden for the nominal cannon/shot clssification! But I also think that the Swedish and Nüremberg pounds are almost identical - it seems to be not the 369 g, but rather a 424 g Nüremberg pound that was used - one that is 15% smaller than the Danish pound.

 

I guess this means that a cannon mentioned as a 24 pounder (or, as here a 42 pounder) on the Swedish drawings, is also a 24 pounder in Danish terms, as they use the same scale (Nüremberg) to classify the guns, but then use the local weight units when they weigh off the cannon or balls. But as mentioned, a nominal 24 pounder, would have fired a 22.44 pound shot (or anything between 22-23 pounds, really...).

 

This also explains why all the well known 'Nye konger', that are known to be (nominal) 24 pounders, are also labelled as such on the swedish drawings.

 

So my interpretation is that, yes, the 42 pounder hel-kartove is a 42 pounder, in both Danish and Swedish terms - it would have fired a 36 Danish Pound shot, but it would have been called and classified as a 42 pounder. In Swedish terms, it would actually have fired a 42 Swedish pound ball. 

 

I will look into more, as there are still some strange things when looking into the armament of certain ships, and I will be back with more soon.

 

BR

Thorbjørn

 

 

 

 

 

 

 

 

 

 

 

[Waldemar]

 

 

Thank you very much, Thorbjørn, for your comment. Not only because of the information itself (and also for pointing out a better copy of Blom's work than the one I had; and the other two Danish works I bought personally as hard copies while in Copenhagen quite a long time ago), but also because I was afraid of boring you, or even irritating, which is definitely not what I want .

Quite at the same time, I began to wonder what a 42-pound cannon really meant in Swedish artillery in 1691, i.e. when the inventory with this particular barrel was made, and I remembered details about calibers in Swedish artillery of that early period (many years ago, I studied this particular subject quite intensively). My information on this very issue comes mainly from two modern works on Swedish artillery, both extremely comprehensive and detailed, and which I still have in my library:

Theodor Jakobsson, Lantmilitär beväpning och beklädnad under äldre Vasatiden och Gustav II Adolfs tid, 1938
Theodor Jakobsson, Artilleriet under Karl XII:s-tiden, 1943

There are, admittedly, also post-war works by Hedberg, Claëson, and Ulfhielm, yet, in technical terms, they do not really contribute anything new and simply rewrite the technical issues from Jakobsson's publications.

But to the point:

The caliber scale invented by Georg Hartmann of Nuremberg in 1540 is ingenious in its simplicity of application, and its main advantage is also that it makes the calculations of round shot and gun bore diameters independent of the specific weight of iron, stone, and lead, which was, after all, variable.

Hartmann's definition is very simple:

¼ cubit (i.e., half a foot or 6 inches) determines a caliber of 24 pounds for cast iron shot (and 37 pounds for lead shot and 7 pounds for stone shot).

Other calibers are simply calculated according to the formula: (diameter_A)³ / (diameter_B)³ = Poundage_A / Poundage_B

 

 

In 1616, Sweden adopted the Hartmann (Nuremberg) scale literally according to its definition, but in such a way that half a Swedish foot (296.7 mm / 2 = 148.35 mm) determined the diameter of the bore of a 24-pound cannon (as opposed to the diameter of a round shot). Indeed, the cannons of the Vasa cast in 1628 perfectly correspond to this measurement within a margin of perhaps 1 millimeter.

However, in 1683, a reform was carried out, whereby from then on, half a Swedish foot no longer determined the diameter of the cannon bore, but the diameter of the round shot. In this way, the diameter of the bore of the base 24-pound cannon increased from 148.35 mm to 155.10 mm (standard NATO calibre, by the way ). From then on, as a result of this reform (using a cast iron density of 7.1 g/cm3, which is the value commonly accepted for calculations of this kind in various countries, and the Swedish skålpund, used in Swedish artillery to determine the weight of projectiles = 425 g), the Swedish base 24-pound cannon fired shot with an actual weight of approximately 28.75 Swedish pounds (skålpund).

Now, let us return to the 42-pound cannon of Danish origin in the Swedish artillery inventory from 1691.

From the above (after calculations), it follows that the cannon marked as 42-pounder must have had a bore diameter of 186.91 mm, for a shot diameter of 178.77 mm. So, in Swedish artillery, it actually fired 50-pound round shots (for 1 skålpund = 425 g).

Converted to Danish units (1 pound = 499 g), this gives an actual round shot weight of approximately 42.6 Copenhagen pounds. As a result, taking into account the necessary windage, the nominal bore diameter of this cannon should correspond to a value of approximately 48 pounds.

This is how it looks from the “Swedish side” of this puzzle. As a result, I must admit that it is indded a 42/48-pound cannon (shot/bore), and I somewhat regret not having thought about the Swedish side of the “equation” earlier.

I hope this is not too complicated and too extensive, but I preferred to provide a complete explanation .

 

 

Edited Friday at 12:54 PM by Waldemar

[TJM]

Thanks for explaining this in detail! And what a further complication with a shift of scale right then!

 

I totally see the arguments, but I can't reconcile the conclusion on the 42 pounder with the other images as well. If the poundage designations on the Swedish drawings were following the 1686 post-reform convention, then all the 24 pounders would actually be nominal 26-27 pounders in the Danish Nuremberg klassification system, firering actual 24-25 Danish pound shots. And this just does not fit with the known poundage of these comon calibers: we know these were nominal 24 pounders (Nuremberg 'talstok' wise) with a 26 pound bore (again, on the  Nuremberg talstok), firing 22.4 Danish pound shots. It seems to me, that the measurements on the Swedish drawings for poundage must be from the old Nuremberg scale, which is identical to the one used in Denmark. 

 

I see it this way because we have the full inventory from 1649 with confirmed dimentions - not just infered from the Swedish drawings (with a potential uncertainty on the scale used), but based on measurements on actual cannons which confirms these - Blom mentions this in the text.

 

 

 

 

Does this make sense?

 

I may well be wrong! But this makes the most sense to me right now 😅. 

 

And i truly appreciate your continued inputs to this @Waldemar, and I am afraid I may seem ungrateful for challenging your well argued/researched points! I am just trying to make sense of it all! 😄

 

 

[TJM]

There are still some very puzzling things about these weights, actual and nominel.

 

I am looking into the Armament of Christian IV's last main ship, the Trefoldighed. This is the one he famously commanded in the Battles of Lister Deep and Kolberger Heide.

 

It had 22 gunports on the main battery and 22 on the upper battery and then a number of smaller ports on the qarterdeck poop deck and forecastle.

 

The lower deck ports were dimentioned for 3/4 kartover and the upper deck ports for 1/2 kartover.

 

People have therefore assumed, that since a hel lartove is 48 pounds, the Trefoldighed must have carried a massive armament of 22 36 pounders and 22 24 pounders. This would have made it incredibly powerfull! You can find this kind of lineup reported on the Danaih Wikipedia. It is not true though. 

 

One of the most capable Danish naval historians of modern times, Niels Probst, writes in Marinehistorisk Tidsskrift in vol 3 1984 that Trefoldighed carried four 3/4 kartover and 18 1/2 kartover on the lower deck and 22 12 pounders on rhe upper deck, and a few 4 pounders on the castles:

 

He is quoting P. Holck for these numbers and it also agrees with what Blom writes: only three ships in 1652 carried 3/4 kartover, one of them was Trefoldighed with 4 pieces.

 

The same is quoted in Marinehistorisk Tidsskrift vol 1 1981:

 

But this it where it stops making sense. Probst calls the 3/4 kartover 36 pounders (this was why I was looking for at 36 pounder!), but it is clear from Blom that by the time of Trefoldighed, the 3/4 kartover was 27 pounders. I am not comfortable with what seems to be an error on Probst's part!

 

Also, he mentions that the upper deck carried 12 pounders, but 12 pounders were not present in the armoury if we go by the nominal weights!:

 

 

There are many cannons with a 12 pound bore though! They would nominally be 10 pounders. Would Probst mix bore and shot poundages when specifying the armament? That does not sound credible.  Again, I am not happy suggesting that Probst got this wrong! He surely must have known Otto Bloms work! 

 

Then there is the possibility that he was quoting not nominal shot weights, but bore or actual shot weight in Danish pounds?

 

But this does not fit either! It would mean the largest 4 guns would be hel-kartover, and Blom clearly says these were 3/4 kartover of 27 pounds. There is simply not one set of measurements that support 36, 24, 12 and 4 pounders!

 

The most reasonable to me is 4x27 pounds, 18x24 pounds and then either 22x10 pounds or 22x14 pounds. 

 

How to settle this? I normally trust what Probst writes, but I cannot make it fit.

 

Is there something combining the Swedish and Danish sources that can make this make sense? 

 

If anyone has any insights or suggestions, I would very much appreciate it!

Edited Friday at 04:18 PM by TJM

[Lieste]

Mixing of bore and shot calibre/diameter is quite common, even in quite respected sources, such as the many works of Dr Summerfield. He has at least a few tables where the smaller guns are misreported.

Even where 'a diameter' of shot is correctly stated it must also be remembered that there are national and period differences in what this 'boulet diametre' represents - It can be a mean gauge from the forges, a low gauge (with a mean and high gauge larger than the nominal), the high gauge (with the mean and low gauge smaller than the nominal) or a mean gauges of the places - the average of the high gauge and the unserviceable gauge. This can materially change the weight of the shot and the comparison of the windage proportions between different pieces - especially if you prefer to converge disparate data sets to a common standard (e.g the mean gauge of reception at places)

[TJM]

Thanks, @Lieste! It is interesting that this mixing of bore and shot weights is not that uncommon. I wonder why? Likely due to very confusing and mixed listings, also combining different pound standards in the sources.

 

I believe that the most reasonable is that the Trefoldighed carried 12 pounders measured by the bore, which would mean 10 pound (Nuremberg) shots, even though the 24 pounders are listed by shot weight - they would have had a 26 pound bore acc. to the tables in Blom's work.

 

It does not seem like the 14 pounders (16 pound bore) were really used as upper armament on the large ships - these were used as main armament for the lighter sub-40 gun vessels.

 

BR

TJM

[Waldemar]

 

I have compared both Swedish artillery inventories from 1670-71 and 1690-91, i.e., before and after the caliber reform of 1684. Firstly, I managed to find some pairs of the same cannons (of Danish origin), which allowed me to conclude that the 1684 reform was simply ignored by those who compiled the second inventory, because the “duplicates” I found are listed with the same caliber in pounds. Alternatively, the reform had in fact been carried out earlier and was only formally approved in 1684 (or something to that effect).

Here is one such example of a pair depicting a Danish cannon (actually three identical guns of the same series), marked as 12-pounders in both inventories (upper one from 1670-71 inventory, the bottom one from 1690-91 inventory):

 

 

Incidentally, in the Swedish 1690-91 inventory, I have also found a second cannon from the “Nye Konger” series, which in turn is not included in the first inventory from 1670-71, and both are marked as 24-pounders (or maybe it's the same cannon of the two?):

 

I am very keen to reconstruct the original Danish caliber scale used in the era of Christian IV, and according to Hartmann's Nuremberg method. I believe that it was defined analogously to the Swedish caliber scale of that era, which used the Swedish foot measure, i.e., in the case of Denmark, it would be the local, Danish foot measure. Of course, in such a way that everything fits together logically, including data from Swedish sources.

Blom's calculations regarding diameters in the above table are somehow not convincing to me, because his starting point for the calculations is apparently the current weight of various, local pounds (Nuremberg and Danish) and the specific weight of cast iron . And yet the beauty and practicality of Hartmann's scale lies precisely in the fact that it deliberately rejects these variable, uncertain components of the calculations. In other words, Hartmann's Nuremberg scale assigns fixed (local) units of length to arbitrarily chosen numbers that determine the nominal poundage of the bore and shot.

I am working on it.

 

 

 

 

Edited yesterday at 11:13 AM by Waldemar

[TJM]

@Waldemar, where do you find these?: 

 

When I search on digitalmuseum.se, I can only find the Thelott drawings, not these. And these are interesting, even though they may be less fine and often have folds. As they carry the poundage designations we have been discussing.

 

How do you search to find them?

 

BR

TJM 

 

[Waldemar]

 

42 minutes ago, TJM said:

How do you search to find them?

 

These illustrative materials were automatically suggested by digaltmuseum algorithms when I was downloading, image by image, Thelott's second set (to supplement my first set of this album, which lacks a scale in centimetres). And I was myself surprised and delighted by this completely accidental find. This find is also a direct result of our conversation, because you asked earlier where you could download Thelott's album, and then I found it ad hoc in digitaltmuseum to point you to a source.

 

However, there is a certain difficulty, namely that all these graphics are made available in a rather chaotic, i.e. single manner, yet, fortunately, these individual reproductions are well described in the metadata. The point is that these inventories were not only compiled on different dates, but are also sorted according to specific fortresses (locations).

 

As a result, when downloading, one has to use various tricks, especially specific search keywords to filter out these different sections in the inventories, and this is a task that takes at least two days.

In this situation, I can of course give you a few sample links to these individual reproductions (a total of about 270 graphics for fortresses in the east and west of Sweden at that time) and you can search for and download them all yourself.

 

But I think it would be better if I sent them all to you already sorted and segregated via WeTransfer (about 1.5 GB) if you give me your email address in a private message. 

 

[Waldemar]

 

I think I got it, that is, the essence of the Danish calibre scale in the era of Christian IV. Its construction is actually quite simple, but it may require a rather difficult mental shift.

The Danish 1/4 ell, or its equivalent – half-foot (I assumed 313.8 mm / 2 = 156.9 mm) was apparently assigned a base nominal poundage of bore of 28 and a base nominal poundage of shot of 31 (in Swedish artillery, after the 1684 reform, 21 and 24 respectively, for the Swedish foot of 296.7 mm).

And that's it. Everything else is calculated according to the formula I gave earlier:

(diameter-A)³ : (diameter-B)³ = Poundage-A : Poundage-B

 

 

In a spreadsheet, it is very easy to automatically perform these calculations for all calibres, including fractional ones and those expressed in ounces or lots (after converting them to decimal notation). How to read the attached table? For example:

sample 1. A gun with a nominal calibre of 26 pounds shoots projectiles of a nominal calibre of 23.5 pounds (one need to compare the dimensions in mm), or

sample 2. A gun with a nominal calibre of 30 pounds – shoots projectiles of a nominal calibre of 27 pounds,

sample 3. A gun with a nominal calibre of 46 pounds – shoots projectiles of a nominal calibre of 41.5 pounds.

Or, from the other side, i.e. starting with the calibre of the shot:

sample 1. Round shot of a nominal calibre of 24 pounds – requires a nominal bore calibre of 26.5 pounds, and has an actual weight of 22.32 Danish pounds,

sample 2. Round shot of a nominal calibre of 27 pounds – requires a nominal bore calibre of 30 pounds, and has an actual weight of 25.11 Danish pounds,
sample 3. Round shot of a nominal calibre of 42 pounds – requires a nominal bore calibre of 46.5 pounds, and has an actual weight of 39.06 Danish pounds.

 

For comparison with Swedish calibres, a similar table with calculated diameters for Swedish artillery guns is needed. Taking as an example a Swedish 24-pound calibre gun (after the 1684 reform): shot 148.35 mm and bore 155.10 mm, which corresponds to a Danish 26-pound cannon (bore),

Or for a Swedish 42-pound cannon: shot 178.77 mm and bore 186.91 mm, which corresponds to a Danish cannon of a nominal calibre of 47 pounds and a nominal calibre of 41.5 pounds (or 42 pounds rounded up). 

In these comparisons, a slight inconsistency arises from the fact that the Danish system had less windage than the Swedish system, in a ratio of 31/28 : 24/21.

As can be seen, there is indeed quite nice equivalence between the nominal calibres in Danish and Swedish artillery, however, quite ironically, in both systems, the nominal calibres were in fact calculated on the basis of somewhat different initial values (i.e. different foot lengths and other base poundages).

 

Cool, isn't it? 

 

 

 

 

Edited 4 hours ago by Waldemar

[Waldemar]

 

To demonstrate how Hartmann's Nuremberg caliber scale (in the Danish variant) actually works, here is a graphic showing the determination of bore diameters for two sample shot calibers — 6-pound and 24-pound.
 

Both scales are pre-calibrated according to the equation given above. In fact, using the poundage was only necessary to obtain the final result in absolute units of length, which was facilitated by Hartmann's double caliber scale (for shot and bore).

 

To find the bore diameter for a 6-pound shot, one would only need to take it from the the upper scale (for the bore) for the respective poundage, i.e. 6-pounds. 

 

And vice versa, to find the shot diameter for a given bore caliber, the reverse procedure was followed.  

 

 

Edited 51 minutes ago by Waldemar

[Waldemar]

 

Returning to Blom's table of calibres, reproduced above, I believe that he assigned too small a shot size to small and medium-sized guns. Why would the windage for an 8-pounder cannon (according to Blom, approx. 9 mm) be almost twice as large as for a 30-pounder cannon (5.36 mm)? It should be the other way around...

 

[TJM]

@Waldemar, thanks you so much! This does make sense - at least it is completely systematic and, which is more important, practical from a real-world use perspective. 

 

And while your numbers vary from Blom in the outer ranges, as you mention, they are close enough to still 'fit' the known nominal calibers for bore and shot weight.

 

The table you made is really useful 😁