Re: Circumnavigation without instruments
Marvin Creamer a Geography professor at Glassboro State College (now Rowan University) did a number of proof of concept crossing of the Atlantic without navigation instruments or charts. The intent was to show that it was possible for early explorers to cross oceans only with knowledge of their environment.
His later circumnavigation, with crew and port stops but with an hour glass as his only navigation instrument was a further demonstration of his hypothesis.
Maybe others have also completed such a journey in the distant past, which was part of what he was demonstrating as a possibility, but I don't think this has been achieved by any other sailor in the recent past.
1970 Havsfidra 20 by Fisksatra
On the Delaware River at Fox Grove Marina Essington PA