Conversation so far:
how did Woodes Rogers prepare?
Rogers was approached by William Dampier, a navigator and friend of Rogers' father, who proposed a privateering expedition against the Spanish.
why did he approach rogers?
This was a desperate move on the part of Captain Dampier to save his career.
what had happened to Dampier's career?
Dampier had recently returned from leading a two-ship privateering expedition into the Pacific, which culminated in a series of mutinies before both ships finally sank due to Dampier's error.

Question: what error had he made?
Self-contained rewrite: what error had Dampier made during his expedition?