Mobula is a student-built autonomous submarine, designed and engineered at NTNU in Trondheim for the 2027 season. It runs fast and flat like a surface boat, then dives — and its own drone lifts out of the hull to stay with it. A custom 532 nm optical link carries data from the submarine up through the water to the drone, where radio simply cannot go.
Mobula is designed, built and tested by students at NTNU in Trondheim. It is the third machine in a line that runs through Ligmax, the roll- and pitch-stabilised autonomous trimaran that competed in 2026 — and it is a deliberate change of category rather than another surface boat.
Ligmax proved the team could take a vessel from bare hull to autonomous operation. Mobula asks the harder question: what happens when the vessel leaves the surface entirely? Diving solves for stealth and sea state, but it costs you your radio link and your view of the world. Mobula's answer is a drone in the hull and a beam of green light through the water.
A project of Dialga, the student engineering organisation behind it.
Most vessels pick a side: fast and flat on top of the water, or slow and quiet beneath it. Mobula is being built to do both with the same faceted hull — planing across the surface when speed matters, then trimming down and swimming when it doesn't.
The hull is chined and faceted to lift and plane, driven by twin propellers on a stern strut. On the surface Mobula behaves like a fast autonomous boat: it covers distance, it carries its drone, and it has a radio link and a horizon to look at.
Control surfaces at the tail — horizontal planes for depth and pitch, vertical fins for heading — take over once the vessel is under. Sea state stops mattering, and so does anything on the surface looking for it.
A pair of cameras sits either side of the forward dome, low and close to the waterline where the vessel needs to see obstacles first.
A lidar dome amidships handles surface navigation. The mast retracts flush into the deck before the vessel dives, and comes back up when it surfaces.
This is the problem that defines the whole project. Put an antenna underwater and it goes deaf — seawater absorbs radio almost immediately, which is why a submarine normally has to come up to say anything at all. Light is the exception, and not all of it: the water column is clearest in the blue-green, right around 532 nm. So that is the wavelength Mobula transmits on.
Mobula carries its own 532 nm LED arrays, recessed into the hull facets in clusters so the beam pattern covers the water above the vessel rather than a single narrow spot. Behind them sits a purpose-built driver circuit that switches the emitters between 5 and 10 MHz.
That switching speed is the entire point. An LED you can only blink slowly is a signal lamp; an LED you can modulate in the megahertz is a data link. The circuit is being designed and built in-house alongside the vessel, because nothing off the shelf does this at the wavelength and rate the mission needs.
The submarine runs shallow and points its emitters up. The drone holds station overhead, watching the water for the signal and carrying it onward to the shore station. Mobula stays under; its link stays open. Neither half works alone — that is why the aircraft is built into the hull rather than bolted on.
A submarine that cannot talk and cannot see above the waterline is a submarine with a problem. Mobula's answer flies. The aircraft launches off the deck, holds station over the vessel, and comes back to a marked pad inside the hull.
A hinged hatch amidships opens onto a bay sized around the aircraft. Closed, it is part of the hull line and the vessel can dive with it. Open, it is a launch and recovery deck.
The bay floor carries a fiducial marker. The drone's downward camera picks it out and uses it to work out its own position and angle relative to the deck — precise enough to put itself back in a bay only slightly larger than it is.
Above the water the drone has the view and the radio path the submarine gave up. It receives the 532 nm signal from below and relays it onward, which makes it part of the vessel's communications, not an accessory to them.
This is the CAD model the vessel is being built from — hull, drone bay, emitter modules, propulsion and the aircraft, as one assembly. Drag to orbit, scroll to zoom.
Three things have to work independently before any of it works together: the hull has to dive and come back, the drone has to launch and land on a moving deck, and the light has to carry data through water. The plan is built around proving them in that order.
Hull and dive-plane geometry locked, drone bay packaged around the aircraft, and the 532 nm emitter and driver design settled on the bench.
Hull fabrication, propulsion and control-surface install, first power-on of the electronics and the optical driver.
Surface running first, then dive trials, then the link: emitters in the water, drone overhead, measuring what actually gets through.
Mobula goes into its first competition season as a complete vessel — submerged, autonomous and connected.
Mobula is led by NTNU students who are highly capable across both software and hardware, and who stay hands-on with every subsystem — from the hull and the optical driver circuit through to the autonomy stack.
Team leaders listed in alphabetical order.
Co-team lead
NTNU student working across the full breadth of the project, from hull fabrication and power electronics to perception and autonomy software.
andreaslindeman.com
Co-team lead
NTNU student equally at home in hardware and software, building everything from the drivetrain and battery systems to the control stack.
jacobhansson.noMobula is student-run and student-funded, out of NTNU in Trondheim. Partners get a real stake in an unusual build — a diving vessel, a drone in its hull, and an optical link none of it works without. Tiers start at 10 000 NOK, and in-kind support counts the same.
Your logo on the hull, on the drone, and everywhere the vessel is shown and run.
Workshop visits, demos and a direct line to the students designing the vessel and its optical link.
Direct access to NTNU engineering students working hands-on with subsea autonomy, drones and optical communications.
