Answer:

sandbar

Answer	Crossword Clue
SANDBAR	Shoreline sight
SANDBAR	Barrier that bumps boat bottoms
SANDBAR	Navigator's concern

SANDBAR	Sailor's hazard
SANDBAR	Ridge in river.
SANDBAR	Mississippi obstruction.
SANDBAR	Offshore island.
SANDBAR	Sailing hazard.
SANDBAR	Shoal.
SANDBAR	Marine hazard
SANDBAR	Hazard to paddle-wheelers

SANDBAR	Shoal
SANDBAR	Boating hazard
SANDBAR	Ship grounder
SANDBAR	Mariner's worry
SANDBAR	Land line?
SANDBAR	Boater's obstacle
SANDBAR	Low tide protrusion
SANDBAR	Current creation, sometimes

SANDBAR	Offshore ridge