Abstract: A testing fixture for investigating the effects of pressure loadings on marine hull and other plate panels in a testing machine includes a liquid-filled bladder adapted to be received on the machine platen, a fixture supported by the machine frame incorporating edge movement restraint members for receiving the panel to be tested and contacting it around its perimetrical edge on both sides, and a measuring element supported by the fixture for measuring the deflection of the panel as the bladder is moved with the platen and pliantly conforms to the surface of one side of the panel to apply a distributed load imposing a bend in the panel inboard of its restrained edges in two dimensions along two axes simultaneously over a substantial area of its surface.