Refractory anchoring devices include a main body and a mounting feature for mounting to a thermal vessel. The main body has the shape of two end-to-end Y's forming a central segment, two branch segments extending from each end of the central segment, and an extension segment extending from each of the four branch segments, to collectively form four unenclosed cell openings that are each semi-hexagonal in shape. Some embodiments include four reinforcement segments with each one extending into a respective cell opening, four voids with each one extending through respective adjacent branch and extension segments, an underbody gap formed under the central segment for refractory interlinking between cell openings, and/or a single stud-welding stud for the mounting feature. Refractory anchoring systems and methods include an array of the refractory anchoring devices arranged and mounted so that the unenclosed semi-hexagonal cell openings of adjacent anchoring devices cooperatively form substantially hexagonal cells.