I'm not a Boat anchor expert but that looks just like the National NC 60. The NC 60 I had was a 1958 a 5 tuber just like that. I've seen a few around at flea markets for $25.00 to $40.00. I had one of these when I was 13. I traded it for a telescope after a tube when out. It didn't pick up to bad for a 5 tube( mine probally could have used an alignment though.
Rod