Ship Model Experiment Tank, Castle Street, Dumbarton

The Ship Model Experiment Tank, built between 1882 and 1883, was designed by E R Mumford, who worked alongside naval architect William Froude, and engineer Professor J McQuorn Rankine. The building features a narrow ashlar frontage with a wide segmental-arched doorway on the right and a window in the corresponding panel to the left. It has plain pilasters, a cornice, and a parapet that rises in the center, which contains a carved panel of William Froude.

The long, narrow workshop extends southward and includes a testing tank. The walls are primarily made of brick, supported by buttresses and round brace-plates, with earth embankments. The slate roof, which has skylights and wooden sarking, is not original. Inside, there are original triangular steel trusses. The long, narrow tank, lined with brick and faced with cement plaster, runs the full length of the shed. Double teak walkways, supported by girders in the side walls, feature double tracks for sliding platforms.

At the south end, there is a brick extension from the 1920s that contains a wavemaker. A modern three-storey office extension on the east side is not included in the listing.