H12276-- OPR-N338-NRT3-11;  H12276 complete multibeam coverage over uncharted (18523) underwater groin. Least depth of 5.37 meters at position: 46°15'44.034" N , -123°32'39.191" W. North end of underwater groin at position: 46-15-44.63N, 123-32-39.42W. S