Centerline (or centerline), английский An imaginary line down the center of a vessel lengthwise. any structure or anything mounted or carried on a vessel that straddles this line and is equidistant from either side of the vessel is on the centerline (or centreline).
Shell (in the united kingdom also fine boat), английский An extremely narrow, and often disproportionately long, rowing boat outfitted with long oars, outriggers to hold the oarlocks away from the boat, and sliding seats, specifically designed for racing or exercise.