Replica of Vasa bronze cannon shot

In late 2012, the Vasa Museum in Stockholm, home of the beautiful but unstable flagship of the Swedish fleet that sank a mile from the shore on its maiden voyage in 1628, put together a team to recreate one of the ship’s 24-pounder bronze cannons. Although Vasa went down in ignominy before it had a chance to make a name for itself, the light cannon that became known as the Vasa gun would be adopted all branches of the Swedish military as the standard artillery piece during the Thirty Years’ War. Sweden was the world’s largest exporter of cannon in the 17th century, and other European countries developed their own versions of the Vasa gun, so learning more about this particular weapon illuminates a far broader stage than just the ship or Swedish naval warfare.

The aim of the project was to make an accurate copy of the cannon and its accessories (mount, ammunition, powder, etc) and then fire it on range. The experiment would be documented with film, audio recordings, doppler radar and pressure monitoring to provide a wide range of data on the ballistic and tactical capabilities of the Vasa gun. Because Vasa was recovered in such excellent condition thanks to the cold, woodworm-inhospitable waters of the Baltic Sea, it was possible for the team to recreate every element of the weapon system, not just the barrel which is the only part that usually survives.

It took almost two years for the project to get to the firing stage. Designing and building the molds and fittings, testing the pour with an iron version first, composing the proper alloy, casting and curing the final product, was no small task. No detailed was spared to make it an exact replica, right down to the decorative motifs on the outside of the gun. The bronze 24-pounder was cast in November of last year. It is ten feet long, weighs 1.5 tons and the alloy is made of around 93% copper, 4-5% tin, and trace amounts of zinc and lead.

Here is video of the casting of the cannon at the foundry last November. The gentleman with the impressive beard is Tom Ward, a Boston sculptor and Fulbright scholar who has been documenting the creation of the replica in an outstanding blog on the Vasa Museum website which I highly recommend reading last page to first so you can see the insane amounts of work that went into this ambitious project:

It took another 11 months after that to get the cannon in proper firing order. On October 2nd, 2014, a Vasa gun fired for the first time in nearly four centuries. In this proofing run, the cannon shot four rounds, the largest of which used 3.3 kilos of powder to generate 10,400 psi of breech pressure and a muzzle velocity of 399 meters per second or mach 1.17. The ball doesn’t beat the speed of sound for long, however. Exponential drag slows it down very quickly.

On Wednesday, October 22nd, the official trials began, witnessed by 200 journalists, museum staff and members of the armed forces.

In this Swedish language video, you can see the cannon being muzzle loaded, details of the replica section of the side of Vasa‘s hull used for target practice, a nice glimpse of the gun and recoil after firing before the entire scene is obscured with smoke, and a close view of the hole left in the target. It’s quite a small hole, really, but it goes all the way through.

Here is film of the cannon being fired at different frame rates:

And here is the proverbial money shot, a detailed view of the cannon being fired at the target, a close-up of the hit, and the impact of the ball on the wood recorded on high speed film so when it’s played back you see every shard and splinter create almost a loose tornado effect. So, so cool.

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16 Comments »

Comment by Joe Bauman
2014-10-24 04:10:23

Fascinating story, thanks! The gunners must have loaded the cannon with too much powder in that last shot (part of the slow-motion videos). Back then, it never would have been allowed to recoil so far, or it would have been a greater threat to the Vasa than to an enemy ship. Maybe the problem was that today’s gunpowder is more potent than that of the 17th century.

 
Comment by Fred Hocker
2014-10-24 06:52:18

Actually, the recoil distance and charge size are correct based on historical and archeological evidence. Recoil distance is approximately 1.6 meters which brings the gun muzzle inboard of the port so that it can be cleaned and reloaded and stops the gun before it encounters obstacles behind it. Charge size was 2.65 kilograms which is 20% less than the 17th century service load and well below maximum load. The gun was proofed to 3.3 kilograms of powder. The gunpowder itself was created especially for this project to represent the performance of 17th century powder. This paticular charge produces approximately 360 m/s muzzle velocity which is consistent with historical data.

Respectfully,

Fred Hocker
Director, Vasa Cannon Project
on behalf of the Vasa gun crew. “We hit what we aim at!”

 
Comment by Karen
2014-10-24 11:18:33

Seeing cannons in parks and museums is great, but seeing them actually fire cannonballs takes things to a whole other level. Wow. And given the apparently, and admirably, obsessive level of historical faithfulness, it’s a bit like stepping back in time. Awesome!

 
Comment by Jason Nowell
2014-10-24 11:48:33

What an incredible job the team did on this project. I wish I could have stood there to hear it fire in person! Many thanks to all of you for the hard work and for adhering to standards that insure historical accuracy. The Vasa has been an inspirational project from construction, sinking, raising, conserving and displaying. The whole undertaking is a remarkable feat, someday I will make it to the museum to see her in person. Excellent work every step of the way, this cannon replica is just another feather in the cap of the entire Vasa team. Bravo!

 
Comment by Fred Hocker
2014-10-25 07:47:03

One of the films shows the initial proof firing, for which no recoil breeching was mounted – we wanted to know what the unrestrained recoil was. With a charge of 1.1 kg, the recoil is about 1 meter. With a charge of 2.2 kg, the gun recoils 5.64 m. With 2.65 kg, the recoil is 7.65 m, and the recoil at 3.3 kg is over 9.5 m, which explains why a breeching system was necessary. The gun would never have been fired on board in this way, and all of the rest of the test program (50 out of 54 rounds) was carried out with recoil restrained by a 5 cm breechrope fastened to two one-ton steel weights.

 
Comment by Joao
2014-10-25 08:55:20

How far was the target?
To be effective, how far should be the distance between the ship and the target?

 
Comment by Ralph
2014-10-27 12:38:58

What are the specifications on the target? What are the materials, thickness, and construction methods? Is it a reproduction of the Vasa’s hull?

The videos are amazing. On the firing side, the noise and smoke of a battle must have been nearly unendurable. I was a little surprised at the recoil – I would have thought the cannon would “jump back” and not just roll.

On the receiving side, the splinters would have been deadly. Did you record the shock wave created when a shot hit the hull? And if a shot actually hit a cannon, watch out!

 
Comment by Midas
2014-10-27 15:40:04

In the video the gunners and the woodworkers made a bet on whether the shot would punch through or not. Afterwards she jokingly complained they didn’t hit the reinforced parts. Beers all around in any case.

 
Comment by Stephen Auslender
2014-10-28 08:35:51

The cannon was not secured as it would have been on the real ship. There would be only a small amount of roll back with the cannon’s movement restrained by heavy ropes. You may see some jump that way.
What amazed me was the vast amount of gun smoke generated by just one shot. Can you imagine what it would been like in the lower deck with a relatively low ceiling and maybe 20 cannon all firing at the same time? Then having to pull the cannon back in position and reload it with all that smoke and noise and cannon balls of the enemy ship hitting and perhaps penetrating the ship? A scene from hell.

 
Comment by Nathan henry
2014-10-28 13:54:09

That’s what breeching tackle is used for–absolutely necessary on the ship, not necessary in the field.

 
Comment by Ken Rochester
2014-10-28 20:58:11

I have just read a book on the “Battle of Trafalgar” almost to the day of the battle!The description of the effect of cannon fire is quite sickening ,the effect of wood splinters and also cannonballs taking bodies to pieces was horrific.After the battle both British and French commanders were horrified at the carnage and expressed a wish that this would never happen again.Unfortunatly things got worse!

 
Comment by Fred Hocker
2014-10-29 08:43:19

The target was at 35 meters, but we fired charges that would simulate a longer range to judge penetration effect. Accuracy is such that we would have been able to hit this small section (4 meters long and 3 meters high) at distances out to about 250 meters without trouble.

 
Comment by Fred Hocker
2014-10-29 08:45:16

The target was an exact replica of part of the side of Vasa at the level of the lower gundeck, built from oak as in the original. Target weight was just over 5 tons. All rounds except one passed completely through the hull structure, up to 75 cm of oak. The one that stuck was a scissor shot fired with a reduced load.

 
Comment by livius drusus
2014-10-29 16:57:16

Thank you very much for commenting, Mr. Hocker. Hearing the details of this fascinating experiment from the proverbial horse’s mouth is invaluable. :thanks:

 
Comment by The Old Salt
2014-10-30 21:37:12

I wonder what the effect would have been had the replica of the VASA’s side been made from old growth oak grown in the (presumably colder)climate then available to the shipbuilders. I would imagine that the second or third growth oak available now would have growth rings much farther apart and thus less resistant to a cannon ball.

Thank you for the test and the video’s; I especially enjoyed the updates by the team. May we see more about the construction of the replica side?

 
Comment by Aarno Junkkari
2016-06-19 04:40:57

This was fantastic! Thank you all!
I am about to make a drawing of a little fortress, redutt, in Puumala of Finland, from the times of Gustav III war. It has had two 6- or 12-pounder cannons. I would be happy to have any illustrations of those “smaller” guns. They must have been swedish made.

 
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