There is possibly some confusion about this charge (MK22) in the above mentioned sources.
It was the large charge (MK20) the one filled with MINOL+RDX, the MK22 limpet was filled with TORPEX.
Each limpet had a 100lbs charge, the reported weight of 200lbs each may come from the fact that the carrier meant to be attached to the side of the X-Craft, which was designed from the MK20 case, had three compartments capable of housing two MK22 overlapped each, so 200lbs per compartment, 600lbs per side until a possible total of 1200lbs on both sides. The said carrier is visible in the attached images, the shape of the charge follows the outline of the compartments.
The MK22 was composed of three cylinders welded side by side on two end plates, the middle one being slightly larger in diameter and containing charge and mechanisms while the outers being the buoyancy chambers. On the upper end plate there were two handles and the firing mechanism access, on the front side the firing mechanism activation control and on the back side two strips provided with three magnets each, arranged in the cavities between the cylinders, for the adhesion to the target.
