A series of centrifuged self-weight consolidation tests of soft clays in which the plastic board drains were installed was carried out to investigate the effect of spacing and width of drain, and the influence of drain deformation caused by following settlement of the clay. Consolidation-time relations of test results were interpreted by current practical solutions. The main conclusions are: 1) the board drain can be converted to the equivalent circular diameter that has the same circumferential length as a board drain, 2) the combined solution of Barron's radial pore water flow and Mikasa's 1-D self-weight consolidation theories well explained the test results.