The base is roughly similar to the carriage shown in my 1851 Ordnance designs, but the elevation control is limited, no precision; it must have been a beast to manipulate and set up; they were designed for short distance firing, set at between 15 degrees and 50 degrees. This one seems to have been a hit or miss technique. The whole principle is to fire high over the defence walls and not be seen doing so by the enemy. The War Office design had been changed in 1856. This one was cast by Harveys of Hayle; they were designed in such a manner and ordered to be delivered by sea direct to the Crimea. Given the years involved, I could probably identify which ships that Harveys used for that purpose; I have no doubt that it would have been one of those built by Samuel Warren, as his forte was devising ships for special cargoes.
5th April 2009, The Plantation, Hayle