Wiktionary
off board
a. 1 (context idiomatic English) Not on or in a means of transportation. 2 (context idiomatic English) Not participating.
Usage examples of "off board".
Dayna twisted around to see what had caught his attention, and found a wipe-off board on the back of the open door.
No warning, no hint of trouble coming, and I was off board when it came?
On the chance the man was off board, perhaps enjoying a drink or a wench in one of Corlin's three taverns, she swept the harbour again, seeking the Ballad's boatswain.
The admiral who had given them a chance at a whole new kind of future was now off board and had disappeared into the transwarp hub's glowing aperture.