The Archaeological Survey of India (ASI) and the state cultural affairs ministry have time and again come under severe criticism over the poor condition of weapons and exhibits in forts across Maharashtra. Some of the cannons and artefacts have also been reported destroyed or missing. On December 16, The Indian Express had reported that a 60-kg cannon had gone missing from Padmadurga, a sea fort in Raigad district.

But all this might just change. A dossier prepared by archaeological researcher Sachin Joshi could give the ASI a much-needed shot in the arm. The dossier has mapped 235 cannons from Chhatrapati Shivaji’s era.

The study by Joshi, a researcher from the archaeology department of Deccan College Post Graduate and Research Institute, and Dr P P Deshpande of the department of mellurgy and material science at the Government College of Engineering, Pune (CoEP), includes detailed metallurgical and technical analysis of the cannons.

Joshi and Deshpande undertook the documentation and analysis of the cannons four years ago. Their project was funded by the Indian National Science Academy, New Delhi, and the University Grants Commission (UGC).

The duo also created 2D drawings and 3D models of the cannons they studied. While the reports, drawings and images of the 235 cannons have already been submitted, the researchers are now working on mapping cannons and weapons in other forts across the state.

“Apart from carrying out a detailed analysis of the engineering and technique used in making the cannons, we have taken their photographs too. Based on these, we prepared 2D drawings and 3D models and documented them so that they could be replicated later if needed, as only half the original number remains today. Hence, at some places, we have even marked their positions through GPS, so as to track them if they are displaced,” Joshi said.

Joshi said that there were a large number of cannons in the forts earlier as documented in old literature. “We found less than half the original number, as many of these cannons were destroyed by corrosion or visitors. People often throw the cannons off fort tops, collect the metal pieces and sell them. Thus, we wanted to document what remains, so that even if some cannons are destroyed, they could be reproduced later,” he said.

The metallurgical and technical studies undertaken by Deshpande included composition, metallographic and rust analysis. “It shed light on the possible manufacturing technology and engineering used in those times,” he said.

According to Joshi, the cannons weighed between 60 kg and 16,000 kg. Three types of forged-welded cannons were found at Kalal Bangadi, Chavari and Landa Kasam. Kalal Bangadi got its name as it is made up of rings. Bangadi in Marathi means bangles or a round ornament.

“The three types of cannons documented were made through welding, casting and forging. It was not known till recently that medieval Indian blacksmiths had the knowledge of such futuristic engineering techniques,” Joshi said.

“The weapons were made of wrought iron. There is no specific recorded history proving this, but it is said that the largest cannon, Kalal Bangadi, 5.4 m in length and 14,000 kg in weight, was brought by the Peshwa’s army in 1735. Another Kalal Bangadi cannon found at Narnala fort at Akola district in Vidarbha region weighs 16,000 kg. These are muzzle-loading types, where gunpowder and projectile objects are loaded from the muzzle (the front end),” Deshpande added.

“Only 45 of the original 70-80 cannons are left at Padmadurga fort; 18 out of 30 in Rasalgad fort in Ratnagiri district; six out of 25 in Sinhagad; and 60 out of 200 in Murud Janjira fort. With the help of drawings, photographs, GPS positions and documents, it is possible to find out which cannons are missing,” Joshi further said.