The 1761 rebuilding plan had envisaged the old wooden double dock being refurbished, but Bentham instead proposed expanding the Basin (building over the double dock in the process) and adding a further pair of single docks built entirely of stone (unlike previous 'stone docks' which had had timber floors). The proposal was accepted; the new docks (now known as Nos 2 and 3 docks) were completed in 1802-3 and are still in place today (accommodating HMS "Victory" and the "Mary Rose" respectively). While constructing a new entrance to the Basin, Bentham introduced the innovation of an inverted masonry arch to tie together the walls on either side. He went on to use the same principle in constructing the new dry docks attached to the basin; it soon became standard for dock construction around the world. In constructing the docks and basin he made pioneering use of Smeaton's waterproof cement. He also designed a "ship caisson" to close off the entrance to the basin (another innovation which soon became a standard design).