Fig. 1. Top: forereef (top row) and backreef (bottom row) models. From left to right: buoyant stiff, extra-buoyant moderately stiff, buoyant flexible and buoyant very flexible. Non-buoyant models were created by adding small lead shot to the flexible models. Rigid models were created by tying stiff models to the thin stainless steel rod at the far left of top row. Markings on ruler are in cm. Bottom: forereef models in `upright' positions in air to demonstrate differences in stiffness. EI decreases from left to right: 1, rigid; 2, stiff; 3, moderately stiff; 4, flexible; 5, very flexible.