The following calculations for an independent tank type B must be specially approved by the Commandant (CG-ENG):
where:
ni = the number of stress cycles at each stress level during the life of the vessel;
Ni = the number of cycles to failure for corresponding stress levels from the Wohler (S-N) curve;
Nj = the number of cycles to failure from the fatigue load by loading and unloading the tank; and
Cw = 0.5 or less. A Cw of greater than 0.5 but not exceeding 1.0 may be specially approved by the Commandant (G-MTH).
46 C.F.R. §154.448