Note the proximity to Penzance (Pensance).
And yes, the 2 men on the beach were pirates, but land pirates. Good for the passerby. Come all that way and survive a shipwreck only to be killed some idiots on the shore.
Penzance immediately came to mind when I saw the references to "Cornwall" and "pirates."
And did the “gentleman” who rescued the mariners have a wild-haired, red-headed wife name Demelza? Oh, wait. The ship went down 100 years before the saga of Poldark. Perhaps they were rescued by Ross Poldark’s grandfather...