Walker worked six hours a day from 1906 to 1912 in total darkness at depths up to , and is credited with saving the cathedral from total collapse.
Razmočena osnova, na jugu in vzhodu zidov je bila okrepljena s pomočjo potapljača Williama Walkerja, temelje so sanirali z več kot 25.000 vrečkami betona, 115.000 betonskimi bloki in 900.000 opekami.