33 U.S.C. § 409: Obstruction of navigable waters by vessels; floating timber; marking and removal of sunken vessels

It shall not be lawful to tie up or anchor vessels or other craft in navigable channels in such a manner as to prevent or obstruct the passage of other vessels or craft; or to sink, or permit or cause to be sunk, vessels or other craft in navigable channels; or to float loose timber and logs, or to float what is known as “sack rafts of timber and logs” in streams or channels actually navigated by steamboats in such manner as to obstruct, impede, or endanger navigation. And whenever a vessel, raft or other craft is wrecked and sunk in a navigable channel, it shall be the duty of the owner, lessee, or operator of such sunken craft to immediately mark it with a buoy or beacon during the day and, unless otherwise granted a waiver by the Commandant of the Coast Guard, a light at night, and to maintain such marks until the sunken craft is removed or abandoned, and the neglect or failure of the said owner, lessee, or operator so to do shall be unlawful; and it shall be the duty of the owner, lessee, or operator of such sunken craft to commence the immediate removal of the same, and prosecute such removal diligently, and failure to do so shall be considered as an abandonment of such craft, and subject the same to removal by the United States as provided for in sections 411 to 416, 418, and 502 of this title. The Commandant of the Coast Guard may waive the requirement to mark a wrecked vessel, raft, or other craft with a light at night if the Commandant determines that placing a light would be impractical and granting such a waiver would not create an undue hazard to navigation.