Originally Posted by featherbaiter
If it is single strand wire, sandpaper, flux then solder.
Per BIA, ABYC, and other marine standards of good practice ... single-strand wire has no place on a boat. I'd go to www.bestboatwire.com
would rewire it correctly ... you're only looking at one wire. If that run had corrosion, I bet the rest does, you'll soon be fighting a losing battle.
That said, yes I have "added" a length to a run to replace a corroded section, and it lasted fine for the 5+ years I held onto the boat and it was working when I sold it. Back then I used butt crimp connectors covered with 5200 and then added heat-shrink covers, sealed by liquid e-tape on the ends. Today I'd use HS connectors covered by adhesive-lined HS.