The ornamental design for a submersiblemixer, as shown and described.
FIG. 1 is a top view of the submersible mixer showing our new design;
FIG. 2 is a front perspective view thereof;
FIG. 3 is left side elevational view thereof;
FIG. 4 is right side elevational view thereof;
FIG. 5 is a rear perspective view thereof;
FIG. 6 is a bottom view thereof;
FIG. 7 is a front view thereof; and,
FIG. 8 is a rear view thereof.
Portions or features of the submersible mixer not shown in the drawings form no part of the claimed design. The broken lines in the drawings form no part of the claimed design.