Fig. 5. Drag force experienced by forereef (filled symbols) and backreef (open symbols) shapes of (A) very flexible models, (B) flexible models, (C) stiff models and (D) extra-buoyant models at increasing unidirectional flow speed. Data are not shown for non-buoyant or rigid models as these comparisons were made by adding lead shot to stiff models, and attaching a steel rod to stiff models, altering their buoyancy and flexural stiffness but not their shape.