It covered 228 feet ( 69.5 m ) of the ship 's length .
Was 7 feet ( 2.1 m ) high , and tapered down to a thickness of 8 inches ( 203 mm ) at the bottom edge .
It covered 228 feet ( 69.5 m ) of the ship 's length and was 7 feet ( 2.1 m ) high , and tapered down to a thickness of 8 inches ( 203 mm ) at the bottom edge .