Chris, Here is a better photo. I do not believe these were used for carrying water for the MGs, mainly they were used for carrying soup and potable water to the troops in the front line. I do know that when a 08 Maxim crew went to the front lines they carried 12,000 rounds of ammo, 15 belts in cans. They would also have a number of the water cans (either 1908 round or 1915 type) for the gun. The water jacket had to be refilled after every 1000 rounds. The cans were non recycling and the water had to be poured back into the water jacket from the spout on the water can. The end of the steam hose would be placed into some water that was left in the can. As the steam from the hose hit the water it was converted back into water again, so the water could be used over and over again. Of course a small amount of water (as steam)may be lost around the front and rear water seals (around the barrel), so you would slowly run lower and lower on your water supply. Since potable water was rare, the crew often collected additional water from wherever they could, often from shell holes. This would keep the gun firing, but would require a more intense cleaning after use since the water could have been contaminated by gas which was corrosive. Dan