axis 21 whereby the two axes 20 and 21 are at an angle or angles relative to the horizontal plane of the bottom wall 11 since the tub comprises two shell sections 16 and 17 of approximately equal length bottom wall 11 is in two sections 11a and 11b of approximately equal length side wall 12 is in two sections 12a and 12b and side wall 13 is in two sections 13a and 13b of approximately equal length the split between the tub sections is indicated by lines 11c 12c and 13c in fig1 tongue and groove type external latches 25 interconnect the wall sections 11a and 11b and 13a and 13b and bridge the splits 11c and 13c whereby the tub shell sections are edgewise interconnected and held together by the latches in their extended positions as seen in fig2 and the wall inner sides are similarly flush across the splits fig5 shows the wall sections 13a and 13b as having thickened rim portions 13a 39 and 13b 39 enabling provision of closely interfitting tongue 28 and groove 29 elements at split 13c to provide a watertight interfit as well as a stiffening joint strengthening the tub at a medial location along its length an elastomeric seal 30 may be provided in the groove 29 to be compressed by the tongue 28 as shown to enhance the watertight connection such a seal and the tongue and groove construction may also be provided at and along the splits 11c and 12c the hinges 18 and 19 are typically provided on adjacent surfaces of laterally flat flange portions 34a and 34b and 35a and 35b on the uppermost extents of the side walls see also the laterally flat.