Difficulty adjustments to improve gameplay: Going quiet now works. • Rig for ultra-quiet, go deep below the layer and slip away: escorts lose you, and ships a helicopter calls in only get a rough position, so they have to find you themselves. • Helicopters drop a torpedo only after confirming you with a second contact. Their sonar listens at the depth where they last found you: fire a decoy, turn and change depth to shake them. • Time compression drops back to 1× as a warning when an attack is coming, not after you've been hit.

This is the biggest update yet. DIFFICULTY AND A SMARTER ENEMY • New Settings screen (gear button on the LOG screen). Choose EASY, NORMAL or HARD, or fine-tune every setting yourself. EASY plays like earlier versions. • Escorts listen harder. Running fast or cavitating gets you found quickly; running quiet keeps you hidden. • Hunters sprint in when they have a good fix, predict where you're heading, and will leave the convoy to come looking for you. • ASW helicopters now come from most escorts, keep working your position and call the ships in. On NORMAL and HARD they carry homing torpedoes. A decoy can fool their sonar. RIG FOR ULTRA-QUIET • A new dive-control option makes the boat far harder to hear. The cost: 5 knots maximum, torpedo reloads pause and depth changes are slower. STRIKE PATROLS • Some patrols now send you against an enemy coast. Use the new VLS panel on the TORPEDO screen to launch land-attack missiles at a target ashore, then get out. • Coastlines and a continental shelf: the water shoals as you close the land, and patrol craft guard the approaches. Active sonar works poorly in the shallows. • The NAV chart is clearer: blue depth bands, land shown, a legend, and zoom out to 160 nm. A NEW SEA • The view through the periscope has been rebuilt: blue water with wind-driven waves, whitecaps, sun glitter and a clouded sky. • Raise the scope and watch the head break the surface as ships rise into view. Lower it and the water closes back over the lens. • In rough seas, waves can wash over the scope. You can't take a sighting through water. SUBMARINES • Submarine positions are secret, even from their own side. A friendly boat looks like any other unknown contact until sonar identifies it, and a torpedo won't tell the difference. Sinking a friendly fails the patrol. • Submarines now come in classes (SSN, SSBN, SSK), each with its own narrowband signature. Ours run their electrical plant at 60 Hz, theirs at 50 Hz. • Once an enemy torpedo is fired at you, you may return fire on submerged contacts for 30 minutes. MISSIONS • The tonnage quota now scales with the shipping in each patrol. • New traffic keeps arriving through days two and three, and completing your objectives early brings bonus tasking. ALSO • Set the LAYER depth button from your own bathythermograph reading. • What's New is available any time from the LOG screen. • Many smaller fixes, including MARK/OBSERVE sometimes vanishing from the periscope.