M4A4 Sherman Crocodile

Allied tankers used logs or field modifications of add-on metal plates. And of course, track skirts or applique armour and even sandbags. M4 Sherman 76mm Gun HVSS Suspension, from the 25th Battalion, 14 Armoured division

25th Battalion 14 Armoured Division

A field mod of an M-10.An armored roof developed by the 813th TD Bn extended all the way to the rear, and had folding panels in the centre, as stated by rudeerude in the link below: http://www.ww2incolor.com/us-armor/m-10.html