Uninterrupted travel outside Canadian waters
If you leave and re-enter Canadian waters without interruption, you do not have to:
no report to the CBSA
follow mandatory quarantine requirements
use ArriveCAN
This includes leisure and touring, including pleasure fishing, sightseeing and other discretionary purposes (known as loop movements)
Whether this applies to current covid protocol (PCR or NATT tests) is open to interpretation. Without interruption, as I understand it, means one cannot moor, anchor or tie up to another water craft while in American waters.