The ornamental design for a portable tow apparatus, as shown and described.
FIG. 1 is a rear perspective view of an ornamental design for a portable tow apparatus;
FIG. 2 is a bottom view thereof;
FIG. 3 is a top plan view thereof;
FIG. 4 is a rear elevation view thereof, showing a sectional view of a control shaft of the portable tow apparatus taken along a section A-A in FIG. 3;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a left side elevation view thereof; and,
FIG. 7 is a right side elevation view thereof.
The broken line showing of an engine assembly inside a frame of the portable tow apparatus, a gear drive positioned on the upper right side of the frame, a fuel tank positioned below the gear drive, and a rope wound alternately within grooves of the portable tow apparatus in FIGS. 1-7, is for the purpose of illustrating environment and forms no part of the claimed design.