The ornamental design for a bathtransferbench, as shown and described.
FIG. 1 is a front perspective view of my design comprising a bath transfer bench;
FIG. 2 is a front side orthogonal view thereof;
FIGS. 3 and 4 are left and right side orthogonal views thereof;
FIG. 5 is a top orthogonal view thereof;
FIG. 6 is a front perspective view thereof mounted over a bathtub with the transfer bench extending over a rim of the bathtub; and,
FIG. 7 is a front perspective view thereof mounted over a bathtub with the transfer bench stowed within the rim of the bathtub.
The dashed lines in the figures represent environmental structure and form no part of the claimed design. Specifically, the environmental structure in FIGS. 6 and 7 includes an example of a bathtub over which the primary deck of the bath transfer benches can be disposed. All other surface(s) or portion(s) of my design not shown in the figures or otherwise described in the specification form no part of the claimed designs.