33 CFR § 117.573 - Stoney Creek.
The draw of the Stoney Creek (S173) bridge, mile 0.9, in Riviera shall open on signal, except:
(a) From 6:30 a.m. to 9 a.m. and from 3:30 p.m. to 6:30 p.m., Monday through Friday except Federal and State holidays, the draw need be opened only at 7:30 a.m. and 5 p.m. if any vessels are waiting to pass.
(b) From 11 a.m. to 7 p.m. on Saturday and from 12 p.m. to 5 p.m. on Sunday, the draw need be opened only on the hour and half hour.
(c) Public vessels of the United States must be passed as soon as possible.