The ornamental design for an offsetumbrellabase, as shown and described.
FIG. 1 is a front elevation view of an assembled segment of an offset umbrella base, according to the present design.
FIG. 2 a top plan view of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 3 is a bottom plan view of a lid of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 4 is an exploded view of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 5 is a front elevation view of a base piece of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 6 is a top plan view of the base piece of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 7 is a front view of the base piece of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 8 is a rear view of the base piece of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 9 is a top view of the lid of the assembled segment of the offset umbrella base of FIG. 1
FIG. 10 is a bottom view of the lid of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 11 is a front view of the lid of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 12 is a front elevation view of the lid of the assembled segment of the offset umbrella base of FIG. 1.
FIG. 13 is a front elevation view of a plurality of the base pieces of the assembled segment of the offset umbrella base of FIG. 1, shown in a stacked configuration; and,
FIG. 14 is a rear view of the stacked base pieces of FIG. 13.
The broken lines shown in the drawings depict portions of the of the offset umbrella base that form no part of the claimed design.