Noun
spar deck (plural spar decks)
(nautical) The upper deck of a ship.
By August she had put into Port Mahon, suffering decay of her spar deck, and she remained there until temporary repairs were completed in March 1827. Source: Internet
First to be removed was the barracks structure on her spar deck, but the limited amount of funds allowed just a partial restoration. Source: Internet
Hollis (1900), p. 188. Marblehead and blockade Bainbridge determined that Constitution required new spar deck planking and beams, masts, sails, and rigging, and replacement of her copper bottom. Source: Internet
The uppermost continuous deck may be called the "upper deck", "weather deck", "spar deck", " main deck ", or simply "deck". Source: Internet