The ornamental design for an elevatedsupplementalbathtub, as shown and described.
FIG. 1 is a side elevation perspective view taken from the top and side of an elevated supplemental bathtub showing my new design, that is shown fitted into a tub enclosure on top of an existing tub and including attachable panels and fixture mounting holes, shown in broken lines;
FIG. 2 is a side elevation side elevation view of the elevated supplemental bathtub taken from the top and one side removed from the tub enclosure and showing a door hinges and latch and fixture mounting holes in broken lines;
FIG. 3 is a view like that of FIG. 2 showing the door as having been opened;
FIG. 4 is a top plan view thereof;
FIG. 5 is a front elevation view thereof:
FIG. 6 is a right side elevation view thereof,
FIG. 7 is a rear elevation view thereof;
FIG. 8 is a left side elevation view thereof; and,
FIG. 9 is a bottom plan view thereof.
The broken lines showing a bathtub surround are included for the purpose of illustrating environment that forms no part of the claimed design.