Abstract: A marine dye composition comprising a water soluble or dispersible dye, particles of a density controlling material having a bulk density and being present in an amount so as to cause said composition to have a relative density of about 1 and to be capable of floating at the surface of a body of water and a water soluble or dispersible binding agent for binding the dye and particles of density controlling material together.

Abstract: A flare (1) for submarine use. The flare (1) is caused to be deployed from a submarine location where it will rise to the surface of the water because of its buoyant casing. A hydrostatic valve means (147) is provided within the casing and it opens when the flare is at or near the surface of the water to render said flare ready to project a flare composition (5) into the air. The hydrostatic valve means (147) is held inoperative by a latch mechanism (51) which is tripped as the flare is deployed from a firing tube at the submarine location. The flare composition (5) cannot be projected into the air until the flare (1) is within a range of vertical attitude determined by inclination means (13). The flare composition (5) cannot be projected into the air until the nose is above water. The flare (1) thus has a sensor (23) at its forward nose to determine that the nose is above the water.