The ornamental design for a marine mount, as shown and described.
FIG. 1 is a front perspective view of a marine mount according to the present invention;
FIG. 2 is a rear perspective view of the marine mount;
FIG. 3 is a top view of the marine mount;
FIG. 4 is a front view of the marine mount;
FIG. 5 is a bottom view of the marine mount;
FIG. 6 is a rear view of the marine mount;
FIG. 7 is a left side view of the marine mount; and,
FIG. 8 is a right side view of the marine mount.
The structural features depicted by broken lines have been shown for the purpose of illustrating portions of the marine mount that form no part of the claimed design.