From the 15th century at the latest, cannons were part of the permanent equipment of many war and merchant ships. However, archaeologists have now discovered a ship cannon that is around 100 years older than previous finds. The cannon found off a western Swedish island is the oldest reliably dated ship's artillery in Europe. There were even remains of a powder bag in the barrel of the gun, which was only around 50 centimeters long. The design and material show that the development of ship cannons was still in its infancy at that time.
Cannons are an integral part of historical accounts of sea battles and pirates, but when did ships begin to be equipped with such weapons? So far there is little information about this. “Our knowledge of the earliest forms of gunpowder weapons and their use in Europe is surprisingly poor,” explain Staffan von Arbin and his colleagues from the University of Gothenburg. The earliest dateable shipwrecks with cannons to date are the “Cavoli” wreck that sank off Sicily in 1440 and the Danish flagship “Gribshunden” from 1495. Most of the historical reports on ship cannons also date from the 15th century.
Cannon barrel including the remains of the powder bag
A relic discovered by an amateur diver off the western Swedish island of Marstrand is now changing this: an amateur diver came across a small cannon, only around 50 centimeters long, lying alone on the seabed at a depth of around 20 meters, without any surrounding shipwreck or other debris. After the find was recovered, it was sent to the Maritime Museum at the University of Gothenburg for further examination. There von Arbin and his colleagues analyzed the small cannon in more detail. It turned out that there were still remains of a cloth bag in the powder chamber at the rear end of the cannon. “These are probably the relics of a cartouche, a fabric shell that contained the powder charge for the cannon,” report the archaeologists. “This suggests that this cannon was part of the ship’s armament and not just a piece of cargo.”
But the fabric remnants were helpful for another reason: They enabled researchers to date the cannon using radiocarbon dating. This revealed that the ship's cannon must have come from between 1285 and 1399. “This means that the Marstrand cannon is not only older than any other find of ship artillery in Europe, it is also the oldest piece of artillery ever discovered,” report von Arbin and his colleagues. The find also proves that powder cartridges were in use earlier than previously assumed.
Insight into the early days of ship artillery
The cannon discovered on the seabed provides valuable insights into the early days of ship artillery: “The Marstrand find represents a major leap forward in our knowledge of early gunpowder weapons, their use and development,” say von Arbin and his team. The comparatively small size of the ship's cannon confirms that sea battles in the 14th century were significantly different than later: instead of firing cannons at each other from a distance, artillery was primarily used from close up as a weapon against the crew of the opposing ship. “At that time, enemy ships were attacked in a similar way to castles and other fortifications on land,” explain the archaeologists.
Experiments were also apparently still going on with the material for the ship's cannons, as chemical analyzes of the Marstrand cannon showed. Because it was not made of cast iron or tin bronze, as was common later, but of a copper alloy with 14 percent lead and small additions of tin, antimony and arsenic. “However, the high proportion of lead in this alloy made the material rather unsuitable for cannon production,” explain the researchers. "Because it made the alloy brittle, which would have caused cracks to form." If this ship's cannon had been fired more often, it could have exploded. “Apparently the negative effects of lead in cannon metal were not yet understood at that time,” said the archaeologists.
In order to find out more about the context of the ship's cannon, von Arbin and his colleagues next want to try to find wreckage from the ship that belongs to it. Given their age and the strong ocean currents at the site, these pieces of debris may now be widely scattered and covered by sediment. “The wreckage is probably heavily degraded and broken, but if we conduct a thorough search of the site and its surroundings, we could still find debris,” says von Arbin.
Source: Swedish Research Council; Specialist article: The Mariner's Mirror, doi: 10.1080/00253359.2023.2225311