Under emergency, in the case of any vessel, boat, water craft, or raft, or other similar obstruction, sinking of grounding, or being unnecessarily delayed in any Government canal or lock, or in any navigable waters mentioned in section
414 of this title, in such manner as to stop, seriously interfere with, or specially endanger navigation, in the opinion of the Secretary of the Army, or any agent of the United States to whom the Secretary may delegate proper authority, the Secretary of the Army or any such agent shall have the right to take immediate possession of such boat, vessel, or other water craft, or raft, so far as to remove or to destroy it and to clear immediately the canal, lock, or navigable waters aforesaid of the obstruction thereby caused, using his best judgment to prevent any unnecessary injury; and no one shall interfere with or prevent such removal or destruction: Provided, That the officer or agent charged with the removal or destruction of an obstruction under this section may in his discretion give notice in writing to the owners of any such obstruction requiring them to remove it: And provided further, That the actual expense, including administrative expenses, of removing any such obstruction as aforesaid shall be a charge against such craft and cargo; and if the owners thereof fail or refuse to reimburse the United States for such expense within thirty days after notification, then the officer or agent aforesaid may sell the craft or cargo, or any part thereof that may not have been destroyed in removal, and the proceeds of such sale shall be covered into the Treasury of the United States.