1. Placed, situated, carried on, etc., under water.
1627. May, Lucan, IV. G ij b. Some from the rocke, some from the shore oppose, Vulteius found this vnder-water traine.
1674. Petty, Disc. Dupl. Proportion, 117. The further Truth whereof doth appear in the Under-water-Air within the Vessels of Water-Divers.
1832. Planting, 109, in Husb. (L.U.K.), III. The wood … is esteemed for under-water-work, as piles, pipes, pumps, sluices.
1886. Pall Mall G., 7 Sept., 2/1. It is not sufficient to lay down the finest system of underwater mines.
1894. Westm. Gaz., 21 Feb., 6/1. A new underwater vessel which might be either a gunboat or an ordinary cargo steamer.
2. spec. In ships: Situated below the water-line.
1882. Nature, XXV. 261. The ships would be secured against sinking by an under-water deck.
1889. Welch, Text Bk. Naval Archit., i. 8. The under-water part of the hull.
