After reading reports of frequent fires in Sherman tanks coming from the British, the Americans decided to investigate. Separate trials were done on tanks cleared of ammunition, and frequent fires did not result from penetrations. However, the story was completely different when the opposite case was tested: the tank had a full loadout of ammo, but no traces of fuel or oil.
90% of penetrations of the fighting compartment and the turret caused a fire! To make things worse, CO2 fire extinguishers proved ineffective, and only large quantities of water could fight this fire.
To test how well water helps against these fires, a rack surrounded by water was tested, but the first penetration tore the entire rack apart due to hydraulic action. A solution was to use concentric cells, with the space between them filled with water, with some air left on top. This proved to protect the ammunition better, with one one cell bursting when hit. A new layout for ammunition was also drafted, which would not only protect it with water, but keep it out of harm's way below the track line.
It was concluded that, short of armouring a tank to the point where it cannot be penetrated at all, this is the best available method of protecting from ammunition fires.
When was this, during Africa or after Sicily?
ReplyDeleteExperiments began while still in Africa, but all the modifications boiled down to field expedient up-armouring of ammo racks. I don't think the wet racks were built until the summer of 1943.
DeleteHow much weight does the water add to the tank?
ReplyDeleteThe new racks including water weighted 900 pounds more according to the report.
ReplyDeleteThe extra 50 rounds of ammunition added another 1000 pounds.