Have seen phosphorus and thermite grenades in action...yes, they would do some damage IF you were able to toss it directly above the engine compartment or where the ammo storage was. And yes, a grenade MIGHT track tank if it lands directly in the tread and wedges itself in the bogey wheels or tread. End of story. Watched a thermite test on a Jeeps engine block and still took a good 3-5 min to burn all the way through, by which time youd be dead and the tank crew would be either climbing out or laughing, depends where ya tossed it.