Section 850.3 - Relationship to Coast Guard marine investigation regulations and procedures(a) The Coast Guard's responsibility to investigate marine casualties is not eliminated nor diminished by the regulations in this part.(b) In those instances where the Board conducts an investigation in which the Coast Guard also has responsibility under R.S. 4450 ( 46 U.S.C. 239 ), the proceedings are conducted independently, but so as to avoid duplication as much as possible.