33 C.F.R. § 117.289

The drawspans of the SR A-1-A Drawbridge, mile 0.3 at Hillsboro Beach, must open on signal; except that, from 7 a.m. to 6 p.m., the drawspans need be opened only on the hour, quarter hour, half hour, and three quarter hour. Public vessels of the United States and tugs with tows must be passed at anytime.