rocks wrecks and obstructions

Obstructions

NOS	NIMA		IHO	Foreign NIMA Charts
		Obstruction, depth unknown
		Obstruction, least depth known
		Obstruction, least depth known, swept by wire drag or diver
		Stumps of posts or piles, all or part of the time submerged
		Submerged pile, stake, snag, well, deadhead or stump (with exact position)
		Submerged pile, stake, snag, well, deadhead or stump (with exact position)
		Fish trap, fish weirs, tunny nets
		Fish trap area, tunny nets area
		Fish haven (artificial fishing reef)
		Fish haven with minimum depth
		Shellfish cultivation (stakes visible)