Abstract: A trailer (10) has a shell (12) of a semicircular shape with U-shaped reinforcing ribs (50) spaced longitudinally along the length of the shell (12). The reinforcing ribs (50) are of an increasing depth from the upper ends thereof to the bottoms thereof at the bottom (55) of the shell (12). A hoist (86) is mounted in inverted relation about trunnions (94) adjacent the bottom of front end wall (90) of shell (12) to minimize stress concentrations and is easily removed by removal of brackets (120) secured to opposed support members (88) on front end wall (90).