An interesting US Signal Corps photograph of welders constructing racks for protective sandbags onto an M4A3E8 Sherman from the 42nd Infantry Division.
taken from fb/History of WW2

Field conversion

A US 105-mm Howitzer Self-propelled Motor Carriage M-7 &quot;Priest&quot;, destined for Normandy, France; Portland, England; 1, June 1944.

An upgraded M4 Sherman with added and crated concrete AWA sand filled bags for added protection against the superior German guns
follow up photo,see 'Field conversion'
taken from fb/War History online