The ornamental design for a skateboard propelling assist pole, as shown and described.
FIG. 1 is a front view of an assembled skateboard propelling assist pole showing a spherically shaped top and middle handgrip, and a ground tip;
FIG. 2 is a right side view of the assembled skateboard propelling assist pole;
FIG. 3 is a top or bottom view of the assembled skateboard propelling assist pole;
FIG. 4 is an isometric view of a disassembled skateboard propelling assist pole,
FIG. 5 shows a close-up view of the parts for either the ground tip or the top hand grip as they are assembled onto the ends of the skateboard propelling assist pole; and,
FIG. 6 is a view showing an embodied usage configuration of the skateboard propelling assist pole.
The broken lines shown in FIG. 6 are for purposes of illustrating environmental structure associated with the claimed design in condition of use, and which forms no part of the claimed design.