The most common use of the Beam was for getting the tank moving again after becoming "High-Centered". This is when the belly of the tank is resting on something higher than the track clearance, leaving the tracks churning around and around without being able to grab something.
Deep mud is frequently the cause with tanks, as the weight of the hull compacts and compresses the mud until it is pretty solid. At the same time the mud around the tracks stays loose. At a certain point the build up of mud can actually lift the hull above the point where the tracks can touch solid ground.
The beam is attached to the tracks on top to both tracks. The tracks are engaged again and the beam is carried down and under the belly of the tank and doing two things: (a.) lifting the tank slightly above the obstruction....and (b.) allowing the power of the tracks to push against the obstruction rather than air. This is usually sufficient to push the tank off of the obstacle.
For the Mark IV, having the beam make several rotations around the tank probably wouldn't be much of a problem as there was nothing for it to catch on.
Hope this Helps,