The ornamental design for a watercooling apparatus, as shown and described.
FIG. 1 is a front-top-left perspective view of a water cooling apparatus showing my new design;
FIG. 2 is a front-top-right perspective view thereof;
FIG. 3 is a front plan view thereof;
FIG. 4 is a back plan view thereof;
FIG. 5 is a right elevation view thereof;
FIG. 6 is a longitudinal cross-sectional view taken along line 6-6 in FIG. 5;
FIG. 7 is a left elevation view thereof;
FIG. 8 is a top elevation view thereof; and,
FIG. 9 is a bottom elevation view thereof.
The broken line showing of the valve and threads in FIGS. 1-9 are included for the purpose of showing environmental structure and form no part of the claimed design.