The traditional explanation emphasizes Cathcart's death and the loss of unified leadership. Better command still required enough specialists to build the batteries the operation needed. Only one engineer remained available, and his death at Fort San Luis left no qualified replacement; the discussion also acknowledges earlier losses on the voyage. A more resilient force would have carried more engineers and spread them among ships to reduce their exposure to the same illness. The scaling ladders showed a related failure to allow for uncertainty. Estimating against the taller visible walls would have been safer than reducing ladder length on an unverified assumption about the lower side.
Chapter · 2:09:25-2:12:15
Why better leadership alone was insufficient
The loss of Cathcart was compounded by inadequate engineering capacity, poor provision for further losses, and siege ladders built without a margin for error.