 Comparisons with the finds from the salvaged Mary Rose itself have provided an opportunity to compare the accuracy of the records provided in the Roll . The picture of the ship has provided clues about basic structural features , such as the number of masts and sails . When compared with an inventory of the ship from 1514 , there is a close match , proving the illustration to be largely accurate . Examination of details in the construction , however , reveals that Anthony allowed himself some artistic licence . The armament in the painted ship appears clearly exaggerated . The heavy stern chasers ( cannon placed in the stern aimed backwards ) mounted through gun ports on the orlop deck , just about the waterline , would not have been feasible because of the lack of an orlop deck and the steep angle ( sheer ) of the ship in this area . The number of gunports in the broadside is inaccurate since it implies two slightly staggered rows of nine ports while the surviving starboard side of the Mary Rose has only one row of gunports on the main deck with seven ports . The accuracy of the forecastle has been more difficult to ascertain since none of it remains ; conflicting interpretations of what it looked like have been suggested . 
