Some trips will establish a boat running order, and depending on experience, some may not.
Some trips will designate a point or lead boat to take the lead, and a sweep boat to come along last.
The point boat is any boat that knows where lunch is, where the camp for the night is, anmd where the pull-in for scouting rapids is.
The sweep boat should have the satellite phone if the group has one, and the major first aid kit. The sweep boat should stay behind all persons who may have stopped to hike.