SH4 has a problem with the
lighting overall. The flares light up your hull when your just under the surface but not the surface of the water

(Not to mention the A.I. fires all the flares in the same area that bares no realtion to wherre. When the source of the spotlights (emitter) is off screen, the spolight beam disappears

. And no lightning of any kind. The new graphic-engine of SH5 should hopefully fix all that.