plain sailing—
1. (Nautical) sailing in open unrestricted waters:
- He can take an observation and is acquainted with that part of navigation called plain sailing.
2. an easy, straightforward task, procedure, etc.:
- Once we’ve fixed the computer it will be plain sailing.
plane sailing—(Nautical) calculation of a ship’s position as if the earth were flat instead of spherical:
- In plane sailing, the principal terms made use of are the course, distance, departure … any two of which being given the others can be found.