The ornamental design for a marineanchor, as shown and described.
FIG. 1 is a top perspective view of a marine anchor of the present invention;
FIG. 2 is a top plan view of the marine anchor shown in FIG. 1;
FIG. 3 is a side view of the marine anchor shown in FIG. 1;
FIG. 4 is a front elevated view of the marine anchor shown in FIG. 1;
FIG. 5 is a bottom plan view of the marine anchor shown in FIG. 1; and,
FIG. 6 is a bottom perspective view of the marine anchor shown in FIG. 1.
The broken line showing of structural elements is included for the purpose of illustrating portions of the article that form no part of the claimed design.