Abstract: Motorized rotational drive system (8) for rotating a framework about an axis of rotation, preferably a horizontal axis of rotation, for a solar collector tracker support system, said motorized system comprising: two ring gear sectors (80) extending in two planes orthogonal to the axis of rotation and provided with means of attachment to said framework; a transmission shaft (82) supporting two pinions (81) in mesh with the corresponding ring gear sectors (80) for synchronized rotation of said ring gear sectors (80); and a motorized drive means for driving the rotation of said transmission shaft (82).

Abstract: A floating, self-propelling, self-ballasting, pivotable bridge system is described. The bridge has a main bridge body with a pontoon-like structure. One end of the bridge has a pivoting system comprising complementary pivot plates, one attached to the bridge and the other on land with a pivot pin attaching them at a pivot point. The other end of the bridge has a releasable locking mechanism. The bridge has ballast tanks for raising and lowering its level in the water. The bridge also has thrusters for propelling itself through the water when it pivots from a closed position spanning a waterway to an open position allowing boat traffic through a waterway.