40-foot Sub For One

The Cyclops needs nine fragment scans - three each of Hull, Bridge and Engine. The gentle route: a Mushroom Forest (the one northwest of the Aurora) covers hull and bridge parts, and the Crag Field or the Underwater Islands wreck covers engines; the east side of the Mountain Island has a bit of everything. Then build it at a Mobile Vehicle Bay floating over water deep enough to hold a 54-metre submarine.

Materials are a proper shopping list (plasteel, enameled glass, advanced wiring, lubricant), but the reward is your mobile home for the deep game - the Lost River chain (Follow the Lost River onward) is far more civilised with a Cyclops.