from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
SAILING INSTRUCTIONS, mar. law. Written or printed directions, delivered by
the commanding officer of a convoy to the several masters of the ships under
his care, by which they are enabled to understand and answer his signals, to
know the place of rendezvous appointed for the fleet, in case of dispersion
by storm, by an enemy, or by any other accident.
2. Without sailing instructions no vessel can have the full protection
and benefit of convoy. Marsh. Ins. 368.