The Oceanic Bridge, mile 4.5, shall open on signal; except that, from December 1 through March 31, the draw shall open on signal, if at least a twenty-four hour notice is given by calling the number posted at the bridge. The owner of this bridge shall provide and keep in good legible condition clearance gauges with figures not less than eight inches high, designed, installed and maintained according to the provisions of § 118.160 of this chapter.
33 C.F.R. §117.734