Max, of course is correct, he answered a question correctly on our latest Historical Photo Contest directly related as to what they were. Below is a photo of two of these guns being used at the siege of Sebastapol during the Crimean War in 1854. This was one of eight contest photos. The distance and the huge wooden mortar beds make the tubes look slightly smaller, but Double D's photo reveals exactly how huge they really were!
Regards,
Mike and Tracy