Reminiscent of Stonehenge, the heritage of these large oddly shaped blocks of concrete that grace harbours all over the world, is somewhat clearer and is proudly South African.
‘Dolosse’ were designed by draughtsman Aubrey Kruger while working for South African Railways and Harbours (Transnet). The name ‘dolos’ came from a remark by Kruger’s father on the similarity they shared with ox knuckle-joint bones that are used by sangomas, the name for South African traditional healers.
The harbours were using large blocks of concrete at the time and due to their flat surface would still get moved by the sea over time. This got Kruger thinking, and led him to repurposing a wooden broomstick during his lunch break – cutting it into three pieces and nailing it back together into an H with a single crooked leg. The design was made to dissipate (instead of block) the energy from the waves and prevent erosion by protecting the sea sand. It was presented to the chief engineer the next day.
Work began on them soon after and ‘dolosse’ can now be seen on shorelines across the globe. 10,000 of these 80-tonne blocks are needed for every kilometre of shoreline. In Danie, Florida the blocks are used as an artificial reef referred to as the Dania Beach Erojacks.
Aubrey Kruger was not an outspoken man and never sought fame even after others accepted credit for his work. His invention will likely remain for many, many years to come.