Section 108.105 - Substitutes for required fittings, material, apparatus, equipment, arrangements, calculations, and tests(a) Where this subchapter requires a particular fitting, material, apparatus, equipment, arrangement, calculation or test, the Commandant (CG-ENG) may accept any substitution that is at least as effective as that specified. If necessary, the Commandant (CG-ENG) may require engineering evaluations and tests to demonstrate the equivalence of the substitution.(b) In any case where it is shown to the satisfaction of the Commandant that the use of any particular equipment, apparatus, arrangement, or test is unreasonable or impracticable, the Commandant may permit the use of alternate equipment, apparatus, arrangement, or test to such an extent and upon such condition as will insure, to his satisfaction, a degree of safety consistent with the minimum standards set forth in this subchapter.(c) The Commandant (CG-ENG) may accept a novel lifesaving appliance or arrangement, if it provides a level of safety equivalent to the requirements of this part and the appliance or arrangement-(1) Is evaluated and tested in accordance with IMO Resolution A.520(13), Code of Practice for the Evaluation, Testing and Acceptance of Prototype Novel Life-saving Appliances and Arrangements; or(2) Has successfully undergone evaluation and tests that are substantially equivalent to those recommendations.(d) During a unit's construction and when any modification to the lifesaving arrangement is done after construction, the owner must obtain acceptance of lifesaving arrangements from the Commandant Marine Safety Center.(e) The OCMI may accept substitute lifesaving appliances other than those required by this part, except for-(1) Survival craft and rescue boats; and(2) Survival craft and rescue boat launching and embarkation appliances.(f) Acceptance of lifesaving appliances and arrangements will remain in effect unless-(1) The OCMI deems their condition to be unsatisfactory or unfit for the service intended; or(2) The OCMI deems the crew's ability to use and assist others in the use of the lifesaving appliances or arrangements to be inadequate.CGD 73-251, 43 FR 56808, Dec. 4, 1978, as amended by CGD 95-072, 60 FR 50465, Sept. 29, 1995; CGD 84-069, 61 FR 25291, May 20, 1996; USCG-2009-0702, 74 FR 49233 , Sept. 25, 2009; USCG-2012-0832, 77 FR 59781 , Oct. 1, 2012