33 CFR §117.311

The drawspan for the State Road 789 Drawbridge, mile 0.05, at Sarasota, need only open on the hour, twenty minutes past the hour, and forty minutes past the hour from 7 a.m. to 6 p.m. From 6 p.m. to 7 a.m., the drawspan must open on signal if at least 3 hours notice is given to the drawtender. Public vessels of the United States and tugs with tows must be passed at anytime.