Completed hewn stones were transported from the stone quarry (located 40-50 metres behind the quay) to the sea by using tipcarts. Here the stones were marked and lifted into place by crane. Since the first part of the walling construction occurred underwater, certified divers were employed. They insured that the ground was level and the stones were placed correctly. Placing the large floor slabs at the bottom proved to be the best solution. Another method was to level the ground with cement-filled hessian sacks. At certain times dynamite was necessary. In these cases, any drilling was performed from a raft. The drill was inserted through an opening, and the divers were held responsible for insuring the hole was adequately drilled. If necessary, several holes were drilled and filled with explosives.

The stones were masoned into courses, block by block with standard dimensions 70/50 and 80/60. Levels were used, and the front line of blocks was drawn up with a cord. The stones on the front had to be smoothed on all six sides. The blocks at the back, however, only needed four smooth sides. Smaller stones were collected at the stone quarry, transported to the quay and tipped over the back of the wall, serving as fill. After each shift, the backside of the wall was finished off. There were two ways to anchor the backmost stones, either they could be given a pointed form or holes could be drilled and inserted with iron (using a hook). It was important that any unevenness be re-masoned and any openings be sealed off, or else it could be destroyed by the sea.