Wintringham advised that a tank that was isolated from supporting infantry was potentially vulnerable to men who had the required determination and cunning to get close. Rifles or even a shotgun would be sufficient to persuade the crew to close all the hatches, and then the view from the tank is very limited; a turret-mounted machine gun has a very slow traverse and cannot hope to fend off attackers coming from all directions. Once sufficiently close, it is possible to hide where the tank's gunner cannot see: "The most dangerous distance away from a tank is 200 yards; the safest distance is six inches." Petrol bombs will soon produce a pall of blinding smoke, and a well-placed explosive package or even a stout iron bar in the tracks can immobilise the vehicle, leaving it at the mercy of further petrol bombs – which will suffocate the engine and possibly the crew – or an explosive charge or anti-tank mine.