ART. 3.  A steam vessel when towing another vessel shall, in addition to her side lights, carry two bright white lights in a vertical line one over the other, not less than 6 feet apart, and when towing more than one vessel shall carry an additional bright white light 6 feet above or below such light, if the length of the tow measuring from the stern of the towing vessel to the stern of the last vessel towed exceeds 600 feet.  Each of these lights shall be of the same construction and character and shall be carried in the same position as the white light mentioned in article 2 (a), excepting the additional light, which may be carried at a height of not less than 14 feet above the hull.

  Such steam vessel may carry a small white light abaft the funnel or
  aftermast for the vessel towed to steer by, but such light shall not be
  visible forward of the beam.

ART. 4. (a) A vessel which from any accident is not under command shall carry at the same height as a white light mentioned in article 2 (a), where they can best be seen, and if a steam vessel in lieu of that light, two red lights in a vertical line one over the other, not less than 6 feet apart, and of such a character as to be visible all around the horizon at a distance of at least 2 miles, and shall by day carry in a vertical line one over the other, not less than 6 feet apart, where they can best be seen, two black balls or shapes each 2 feet in diameter.

(b) A vessel employed in laying or in picking up a telegraph cable shall carry in the same position as the white light mentioned in articles (a), and if a steam vessel in lieu of that light, three lights in a vertical line one over the other, not less than 6 feet apart.  The highest and lowest of these lights shall be red and the middle light shall be white, and they shall be of such a character as to be visible all around the horizon at a distance of at least 2 miles.  By day she shall carry in a vertical line one over the other, not less than 6 feet apart, where they can best be seen, three shapes not less than 2 feet in diameter, of which the highest and lowest shall be globular in shape and red in color and the middle one diamond in shape and white.

  (c) The vessels referred to in this article when not making way
  through the water shall not carry the side lights, but when making way
  shall carry them.

  (d) The lights and shapes required to be shown by this article
  are to be taken by other vessels as signals that the vessel showing them
  is not under command and can not, therefore, get out of the way.

  These signals are not signals of vessels in distress and requiring
  assistance.  Such signals are contained in article 31.