Abstract: A support device for a heavy horizontal storage vessel having convex ends and walls which are thin in relation to its diameter comprises, at each end of the vessel, a short annular stiffener (8) coaxial with the end. It is of sufficient diameter to distribute and reduce stresses to a low value. A flexible semi-circular steel plate member (9) cradles the stiffener with limited clearance (11). A rigid annular plate member (10) is disposed in substantially the same vertical plane as the stiffener (8) and semi-circular plate member (9) to form a cradle for plate member (9) over part of its periphery. The radius of curvature of the annular plate member (10) is sufficiently greater than that of the semi-circular flexible plate member (9) to permit differential radial expansion. The rigid annular plate member is thus axially and laterally connected to the stiffener by appropriate structure.