{HEAD ~ The method} and {TAIL ~ structure} includes defining an inner circumferential seat, and an outer circumferential seat, in the vessels bottom, those seats being disposed inside of and outside of, respectively, the circular wear path previously formed in the bottom 
{ HEAD ~ The method } and { TAIL ~ structure } includes defining an inner circumferential seat , and an outer circumferential seat , in the vessels bottom , those seats being disposed inside of and outside of , respectively , the circular wear path previously formed in the bottom
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