Subnautica Cyclops Guide: Fragments Modules and Safe Piloting

The Cyclops is the closest thing Subnautica has to a houseboat. It's 54 meters long, it carries a Seamoth or Prawn Suit in its belly, and you can bolt fabricators, lockers, and grow beds right onto the walls. It also turns late-game exploration from a series of terrifying swims into a road trip. The catch is that the sub is loud, power-hungry, and big enough that leviathans treat it like a chew toy if you pilot it badly. Here's the whole road: scanning the fragments, paying the material bill, picking upgrades, and keeping the boat alive when something with far too many teeth shows up.

Finding Cyclops Fragments

Most blueprints in this game need one set of fragments. The Cyclops needs three separate sets, and each set takes three scans. That's nine fragment scans total, split across the hull, the engine, and the bridge. Every finished set moves the big blueprint a third of the way, and your PDA tracks each one separately, so you can see exactly what's still missing.

| Blueprint | Scans needed | Easiest spots | | --- | --- | --- | | Cyclops Hull | 3 | Mushroom Forest (either one), Sea Treader's Path, northwestern Mushroom Forest wreck | | Cyclops Engine | 3 | Crag Field, Underwater Islands wreck, Mountains and its wreck, Aurora, Crash Zone trench | | Cyclops Bridge | 3 | Mushroom Forest, Sea Treader's Path, Crash Zone trench, northwestern Mushroom Forest wreck |

The hull and the bridge are the friendly ones. Both spawn all over the Mushroom Forests and along the Sea Treader's Path, which are about as calm as this ocean gets. Bring a Seamoth, cruise the treeline, and scan every broken chunk of grey hull you see. The northwestern Mushroom Forest has a wreck absolutely surrounded by fragments, and a lot of runs end with both blueprints done before you head home. Some players drop a small base with a scanner room nearby and ping for fragments from the map screen, which makes the hunt almost lazy.

The engine is the awkward one. The classic route is the Crag Field, which usually hands over engine pieces without a fight. The Underwater Islands wreck is another solid stop up north, near Lifepod 3 if you've picked up its signal. Plenty of players grab their last engine scans on quick dashes into the edge of the Crash Zone from the kelp forest, and the Aurora itself holds engine fragments too if you're already heading there for the story.

One shortcut deserves a warning. The east side of Mountain Island can hold all three part types in one visit, which sounds great on paper. The problem is a Reaper Leviathan patrols that area along with a bunch of Bonesharks, and the fragments sit below 200 meters. It's a real run, just not a first run. Do the Mushroom Forest first, swing through the Crag Field, and save the island for a day you're feeling brave.

Building the Submarine

You build the Cyclops at the Mobile Vehicle Bay, the same floating platform you used for your Seamoth. If you somehow skipped it, the bay costs 1 Titanium Ingot, 1 Lubricant, and 1 Power Cell at any fabricator. By this point in a save you almost certainly own one, so the real work is the shopping list.

The finished recipe at the bay:

| Ingredient | Amount | | --- | --- | | Plasteel Ingot | 3 | | Enameled Glass | 3 | | Lubricant | 1 | | Advanced Wiring Kit | 1 | | Lead | 3 |

Those middle-tier items hide a chunk of raw material, so here's the translation. Each Plasteel Ingot is 1 Titanium Ingot plus 2 Lithium, and each Titanium Ingot is 10 Titanium, so the ingots alone run you 30 Titanium and 6 Lithium. Each Enameled Glass is a regular Glass plus a Stalker Tooth, which means quartz and some quality time getting bitten by Stalkers in the kelp forest (they drop teeth when they chew on metal, so towing metal salvage around helps). The Advanced Wiring Kit breaks down into a Wiring Kit, 2 Gold, and a Computer Chip, and the Lead you'll just mine raw. It looks like a mountain of stuff, but a couple of focused trips covers it.

Build in open water near your main base, somewhere flat with room to spare. The sub comes out at the surface, and you want space to park it without scraping coral heads on day one. Once it's floating, climb in through the keel hatch and look around. The boat spawns with all six power cells fully charged and two fire extinguishers on the wall, one by the damage console and one in the engine room, which is a nice touch you'll appreciate later.

The layout is worth a quick tour. The bridge up front is where you pilot. The big midsection room is your empty canvas, and it's the best spot for a fabricator, extra lockers, and an indoor grow bed or two so long trips don't mean starving. Below the keel you get five built-in storage lockers with 18 slots each, which is a ton of free space. The engine room in the back holds the six power cells, three per side, plus the upgrade fabricator and the six-slot upgrade panel you'll be using constantly. And don't skip the starboard HUD, where you can rename the boat and pick a paint job. A named sub is a loved sub.

Choosing Upgrade Modules

All Cyclops modules are crafted at the little fabricator in the engine room, then slotted into the panel on the port side. Six slots, so you can't take everything. Some blueprints unlock free after your first build, but several live in data boxes tucked into wrecks, so a few detours are part of the deal.

Depth modules come first, always. The stock hull is certified to 500 meters, which walls off most of the late game. The ladder goes like this:

| Module | Crush depth | Crafted from | | --- | --- | --- | | MK1 | 900 m | 1 Plasteel Ingot + 3 Ruby (engine room fabricator) | | MK2 | 1300 m | MK1 + 1 Plasteel Ingot + 3 Nickel Ore (Modification Station) | | MK3 | 1700 m | MK2 + 1 Plasteel Ingot + 3 Kyanite (Modification Station) |

Note that MK2 and MK3 are upgrades of the previous module, made at a base Modification Station, not fresh crafts. Kyanite only shows up deep, so MK3 is usually a mid-late-game errand, and that's fine. Going past your crush depth drops a warning from the AI and then starts eating the hull fast, so the module isn't optional.

After depth, the Engine Efficiency Module is the best value in the game for this boat. It cuts the cost of moving to a third of normal. You can grab one for free from a console in the Aurora's drive core room, and if you'd rather craft it, the blueprint unlocks once your first Cyclops exists. It only helps with movement, not silent running or gadgets, but movement is your biggest drain, so it pays for itself within minutes.

The Cyclops Thermal Reactor Module is the endgame king. Its data box hides in the Grand Reef wreck, the Mountains wreck, or the northwestern Mushroom Forest wreck. Above 30 degrees Celsius at the engines it starts trickling charge back into your cells, hitting a full 1 energy per second at 60 degrees. Park next to a lava vent and the sub literally refuels itself, which deletes your power problems for the rest of the game.

A few more, quick:

• Cyclops Sonar Upgrade (Blood Kelp Trench, Bulb Zone, or Grand Reef wrecks): pings the terrain onto your HUD. Costs 10 energy per ping, roughly every 5 seconds while active. Gorgeous in the dark zones. Reapers don't even react to it.
• Cyclops Shield Generator (Dunes wreck, Sea Treader's Path wreck, or the Deep Grand Reef Degasi seabase): full invincibility bubble for 50 energy up front plus 10 per second. It even shrugs off crush depth damage and knocks Lava Larvae off the hull.
• Cyclops Fire Suppression System (Blood Kelp Trench, Sparse Reef, or Underwater Islands wrecks): kills every fire on board in about 10 seconds for zero energy. Locks the doors for half a minute and needs 200 seconds to recharge.
• Decoy Tube Upgrade: blueprint unlocks free with your first sub. Tube capacity goes from 1 decoy to 5. Cheap, and you want it.
• Docking Bay Repair Module: auto-repairs whatever vehicle is parked in the bay. Quality of life, nothing more.

For a general-purpose loadout, run depth module, Engine Efficiency, Thermal Reactor, Sonar, Shield, and Fire Suppression. That covers deep water, long range, dark water, and bad days, in that order.

Managing Power and Noise

Six power cells, three per side of the engine room. Standard cells hold 1200 energy between them; ion cells hold 6000. Cells drain one at a time, in order, and you can pop them out by hand to swap in spares, so carrying two charged backups is cheap insurance.

Here's the whole game on one table:

| Speed | Energy per minute | Top speed | Noise reach | | --- | --- | --- | --- | | Ahead Slow | 4.5 | 6.7 m/s | 82.5 m | | Ahead Standard | 9.9 | 8.9 m/s | 105 m | | Ahead Flank | 19.8 | 10.4 m/s | 150 m |

Look at flank speed for a second. It costs more than four times what slow does, for barely half again the speed, and it's the loudest setting on the boat. It also overheats the engine if you hold it longer than about 20 seconds, and after the overheat warning the game starts rolling dice on an engine room fire every 2 seconds. Flank is for getting chased, not travel. Slow is the honest default, and with the Efficiency Module installed it gets absurdly cheap at 1.5 energy per minute. Turning while you move, or diving while you move, tacks on extra drain too, so a straight line is a cheap line.

Silent Running is the other big lever. It cuts your noise in half and switches the lights off, but it burns 1 energy every second, and no, the Efficiency Module doesn't soften that. Worse, it keeps draining even with the engine off, so leaving it toggled while you hop out to mine for an hour will come back to an empty battery. From a full standard set of cells, silent running alone eats everything in about 20 minutes. Also remember that exiting the pilot seat does not shut the engine down, and the lights stay exactly how you left them.

Noise is what the deep uses to find you. The faint blue sphere on the holographic display is how far away things can hear you, and hostile contacts show as yellow triangles when they're oblivious and red when they've heard something they don't like. Floodlights don't add noise, but you can't have them on during Silent Running anyway. Two weird exceptions: Crabsquids will still zap the sub with an EMP if your headlights are on, engine off or not, and Lava Larvae latch on and sip power no matter how quiet you are. Flick the shield on and off to shrug the larvae off.

For recharging, you've got options in ascending order of effort. Swim spare cells home to a base charger. Build a Power Cell Charger inside the sub itself, though note it pulls from the same battery it feeds, so it's only useful paired with the Thermal Reactor in hot water. Or go find Ion Power Cells and stop thinking about energy for the rest of the save. One more drain to remember: a docked Seamoth or Prawn recharges off the sub's cells, so your ride home costs a little every trip.

Escaping Leviathan Encounters

First, the good news. Bonesharks and Stalkers bounce off the hull without doing a thing, and Warpers completely ignore you while you're inside. The short list that can actually hurt the boat: Reaper Leviathans in the Crash Zone, Dunes, and Mountains; Ghost Leviathans around the Grand Reef, the Lost River, and the northern Blood Kelp; Sea Dragons in the lava zones; plus Ampeels and Crabsquids in the blood kelp and bulb regions. Everyone on that list hunts by sound. That's the entire fight.

So who do you deal with when a red triangle starts closing in? Run this playbook:

1. Kill your speed first. Drop to Ahead Slow or come to a stop, and hit Silent Running. Half the noise, right now.
2. If it's still coming, launch a Creature Decoy and turn. The tube fires from the midsection with a slight delay, so angle away before it pops, or the attacker might swing into you anyway. Then creep out at slow speed while it chases the noisy yellow orb on your display. Do not floor it. Flank makes you louder than your own decoy, and the trick stops working.
3. If it's already on you, shield up and take the hits. The bubble negates all incoming damage for as long as you can afford the 10 energy per second, and anything touching it gets flung off like you knifed it.
4. Last resort, the oldest trick in the book: engine fully off, silent running off, sit still. A powered-down Cyclops makes zero noise, and attackers lose interest in a quiet boat fast. Eat a bump or two, wait for the red triangle to fade back to yellow, then quietly motor away.

After any fight, do your checks. Fires come first, since they spread and chew through hull while you watch, so grab a wall extinguisher or trigger the Fire Suppression System. Then look at the damage hologram on the port side of the bridge, which marks every hull breach. Breaches only repair from outside, so pop the hatch, swim the hull, and fix the glowing spots with your Repair Tool. The sub has 1500 health, and the top 150 of it regenerates on its own like a shield as long as the hull holds, so small scrapes genuinely do heal. Big ones don't, and a Cyclops at zero explodes, though the AI screams a warning first and leaves a wreck you can still loot, lockers intact.

Two closing things worth knowing. A docked vehicle with a shallower crush depth than the sub takes no damage while it's docked, so your Seamoth can ride down to 1700 meters in the bay without a scratch. And once you craft that Shield Generator, keep it safe. The Neptune rocket cockpit you'll eventually need to leave the planet takes a Cyclops Shield Generator as a part, so every module slot you fill now is one step closer to the ride home.