Tractor units for transporting elongated loads

A tractor unit for transporting an elongated load, comprising:

• a tractor unit body in the form of a closed generally triangular chassis;
• a wheel set comprising three ground-engaging wheels, wherein one of said wheels is mounted at each corner of the triangular chassis, such that the wheels are positioned to define a triangle when viewed in plan view, all of which are driven, said wheel set supporting, driving and steering the tractor unit body;
• and
• a load engagement mechanism for mounting to and supporting said elongate load, said load engagement mechanism being mounted on said tractor unit body and configured to be lowered toward ground level at a point outside the periphery of the triangular chassis for mounting to said elongate load, wherein said load engagement mechanism is mounted pivotally on the tractor unit body about a substantially vertical axis located at the incentre of said triangle;
• wherein the three wheels of the wheel set are steerable wheels whose orientation may be varied to transform the wheel set between an aligned mode of operation and a carousel mode of operation;
• wherein in the aligned mode of operation the wheels of the wheel set are aligned with one another when in a neutral steering position causing the tractor unit body to follow a straight line when driven with neutral steering, and are steerable to deviate the direction of travel to either side of said straight line;
• wherein in the carousel mode of operation the wheels of the wheel set are oriented relative to one another with their axes of rotation intersecting at said vertical axis, whereby when the one or more driven wheels are driven in said carousel mode of operation, the tractor unit body rotates about said vertical axis;
• wherein said load engagement mechanism remains in fixed position relative to the ground by counter-rotation of the load engagement mechanism about said vertical axis relative to the tractor unit body as the tractor unit body rotates.