(a) Drawtenders of bridges listed in this section shall acknowledge sound signals as follows:
(1) When draw can be opened immediately, two prolonged blasts followed by one short blast or three loud and distinct strokes of a bell.
(2) When draw cannot be opened immediately, or when it is open and must be closed promptly, two prolonged blasts or two loud and distinct strokes of a bell. This signal may also be used by a vessel to countermand its call signal.
(b) When fog prevails by day or by night, the drawtender of each bridge listed in this section, after giving the acknowledging signal to open, shall toll a bell continuously during the approach and passage of vessels.
(c) The draws of the twin, SR 529, highway bridges across the Snohomish River, mile 3.6, at Everett shall open on signal if at least one-hour notice is given. On weekdays, Monday through Friday, notice for openings shall be given by marine radio, telephone, or other means to the drawtender at the SR 529 highway bridge across Ebey Slough, at Marysville, and at all other times to the drawtender at the twin SR 529 bridges at Everett. One signal opens both draws. During freshets, a drawtender shall be in constant attendance and the draws shall open on signal when so ordered by the District Commander.
(d) The draw of the SR2 highway bridge across the Snohomish River, mile 6.9, at Everett, shall open on signal if at least four hours notice is given. During freshets, a drawtender shall be in constant attendance and the draw shall open on signal when so ordered by the District Commander.
(e) The draw of the Burlington Northern Santa Fe railroad bridge across the Snohomish River, mile 15.5, at Snohomish, need not be opened for the passage of vessels.
(f) The draw of the Burlington Northern Santa Fe railroad bridge across Steamboat Slough, mile 1.0, near Marysville, shall open on signal if at least four hours notice is given. The opening signal is one prolonged blast followed by one short blast and one prolonged blast.
(g) The draws of the twin, SR 529, highway bridges across Steamboat Slough, miles 1.1 and 1.2, near Marysville, shall open on signal if at least four-hours notice is given. On weekdays, Monday through Friday, notice for openings shall be given by marine radio, telephone, or other means to the drawtender at the SR 529 highway bridge across Ebey Slough, at Marysville, and at all other times to the drawtender at the twin SR 529 bridges at Everett. One signal opens both draws. During freshets, a drawtender shall be in constant attendance and the draws shall open on signal when so ordered by the District Commander.
(h) The draws of the SR 529, highway bridge, across Ebey Slough, mile 1.6, at Marysville, shall open on signal if at least one-hour notice is given. On weekdays, Monday through Friday, notice for openings shall be given by marine radio, telephone, or other means, to the drawtender at this bridge, and at all other times to the drawtender at the SR 529 bridges across the Snohomish River at Everett. During freshets, a drawtender shall be in constant attendance and the draws shall open on signal when so ordered by the District Commander. [CGD 82-025, 49 FR 17452, Apr. 24, 1984, as amended by CGD13 84-13, 49 FR 35628, Sept. 11, 1984; CGD13 85-10, 50 FR 25961, June 24, 1985]