The ornamental design for a watercraft-mounted computing device holder, substantially as shown and described.
FIG. 1 is a perspective view of a watercraft-mounted computing device holder.
FIG. 2 is a front view of the watercraft-mounted computing device holder of FIG. 1.
FIG. 3 is a back view of the watercraft-mounted computing device holder of FIG. 1.
FIG. 4 is a left side view of the watercraft-mounted computing device holder of FIG. 1.
FIG. 5 is a right side view of the watercraft-mounted computing device holder of FIG. 1.
FIG. 6 is a top view of the watercraft-mounted computing device holder of FIG. 1; and,
FIG. 7 is a bottom view of the watercraft-mounted computing device holder of FIG. 1.
The broken lines illustrating portions of the watercraft-mounted computing device holder represent the boundary of the claimed design. The broken lines form no part of the claimed design.