From Wikipedia:
In navigation, a rhumb line (or loxodrome) is a line crossing all meridians of longitude at the same angle, i.e. a path derived from a defined initial bearing. That is, upon taking an initial bearing, one proceeds along the same bearing, without changing the direction as measured relative to true north.
I suppose one can reverse that statement, so that any line that maintains a constant heading to true north is a rhumb line?
So the equator and the parallels are also rhumb lines?
regards,
HN39