The board of supervisors shall require the keeper of every toll bridge or ferry to give bond with two or more sufficient sureties, to be approved by the president and clerk of the board in a penalty, to be fixed by the board, of not less than Five Hundred Dollars ($500.00) and not more than Two Thousand Dollars ($2,000.00), and conditioned to keep the bridge or ferry at all times in good repair so as to secure the safe transportation, on the payment of the fixed tolls, of all persons and property, and in all things to comply with the law and the reasonable orders of the board regulating the keeping of such toll bridge or ferry, but saving to the keeper a reasonable time within which to repair damage done by a sudden freshet, storm, or other unforeseen accident.