The draw of the Quincy Weymouth SR3A bridge, mile 3.5 between Quincy Point and North Weymouth, Massachusetts, shall open on signal, except that:

(a) From 6:30 a.m. to 9 a.m. and from 4:30 p.m. to 6:30 p.m., Monday through Friday, except holidays observed in the locality, the draw need not be opened.

(b) The draw shall open on signal at all times for self-propelled vessels greater than 10,000 gross tons.

(c) From noon to 6 p.m. on Thanksgiving Day, from 6 p.m. on December 24 to midnight on December 25, and from 6 p.m. on December 31 to midnight on January 1, the draw shall open on signal after at least a two-hour advance notice is given by calling the number posted at the bridge.