[Code of Federal Regulations] [Title 46, Volume 7] [Revised as of October 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 46CFR171.106] [Page 138-139] TITLE 46--SHIPPING CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) PART 171_SPECIAL RULES PERTAINING TO VESSELS CARRYING PASSENGERS--Table of Contents Subpart D_Additional Subdivision Requirements Sec. 171.106 Wells in double bottoms. (a) This section applies to each vessel that has a well installed in a double bottom required by Sec. 171.105. [[Page 139]] (b) Except as provided in paragraph (c) of this section-- (1) The depth of a well must be at least 18 inches (45.7 cm) less than the depth of the double bottom at the centerline; and (2) The well may not extend below the horizontal plane C illustrated in Figure 171.105. (c) A well may extend to the outer bottom of a double bottom at the after end of a shaft tunnel.