I assume that's the standard 19/16, 19 strands of 16 guage hard drawn copper
wire. That's good stuff and it is heavy, requiring serious insulators and
supports.

That's what was used for main and emergency antennas on old US merchant vessels
as well as the emergency antenna (coiled up) for vessels with vertical
antennas.

Ideally, stainless steel thimbles should be used at the ends. These may be
purchased at places that sell marine hardware.

Really, for SWLs, the smaller 7/16 would be better. But it, too, is rather
stiff and requires similar handling (including smaller thimbles). 7/16 was used
for the safety link for the antennas using 19/16 wire.

Bill, K5BY