(作修饰语用)(船只)远在只见桅杆, 看不到船身的地方(因船身在地平线之下)
(坦克等)隐蔽在能观察敌人并能向其射击的地方

Hull \Hull\, n. [OE. hul, hol, shell, husk, AS. hulu; akin to G.
h["u]lle covering, husk, case, h["u]llen to cover, Goth.
huljan to cover, AS. helan to hele, conceal. [root]17. See
{Hele}, v. t., {Hell}.]
1. The outer covering of anything, particularly of a nut or
of grain; the outer skin of a kernel; the husk.

2. [In this sense perh. influenced by D. hol hold of a ship,
E. hold.] (Naut.) The frame or body of a vessel, exclusive
of her masts, yards, sails, and rigging.

Deep in their hulls our deadly bullets light.
--Dryden.

{Hull down}, said of a ship so distant that her hull is
concealed by the convexity of the sea.