Flexible structures for use with dock seals and shelters are disclosed. An example flexible structure includes an elongate flexible panel assembly having first and second longitudinal edges and at least one flexible thin-walled member having a length along a longitudinal axis of the elongate flexible panel assembly. The at least one flexible thin-walled member is configured to have a cross-sectional geometry that provides sufficient rigidity to enable the elongate flexible panel assembly to be cantilevered from a surface via the first longitudinal edge without substantial deformation of the cross-sectional geometry of the at least one flexible thin-walled member along the length of the at least one flexible thin-walled member.