"6 IN. DIA STEEL PIPE,18 IN. LG,MTD ON CHANNELS AND PLATES 31-5/8 IN.BY 20 IN. BY 9 IN. O/A DIM.,FOR SUPPORTING AND PREVENTING CHAFING OF THEPONTOON WARPING TUG STERN ANCHOR LINE,USED W/ANCHOR HOUSING,FSN2040-806-4273,NAVFAC DWG 879160 MK NO. WT8,ZZZTJB8"