Slitherine

The manual says:
"A convoy surrounded by friendly naval combat units moves THROUGH one of those units in the convoy movement phase.".
I understood that if not completed surrounded the convoy will choose one of the empties hexes to move, but not.
The convoy chooses a random path even through friendly units, is it correct?

If memory serves, the random move can go both thru friendlies or any empty hex. Haven't really paid attention though