Building a competition AUV for SAUVC or RoboSub: parts list

An AUV is a student ROV with the tether cut: it carries its own battery and its own brain, and a diver must be able to switch it off. This is a compact eight-thruster vehicle built for pool competitions, with the switches, cameras and computing those competitions ask for.

What the competitions ask for

SAUVC, the Singapore AUV Challenge, is the nearest international competition for Indian teams. The 2026 run is 15 minutes in a 25 × 16 m indoor pool: pass through a gate 16 m away, drop a ball into the right drum, pick it up again, and bump coloured flares in a commanded order. The 2026 rulebook caps the vehicle at 52 kg in air and a 140 × 100 × 100 cm box, and gives bonus points under 42 kg and under 70 × 50 × 50 cm. It requires a kill switch that turns off the vehicle, thrusters included, that a diver can reach easily, marked in a bright colour.

RoboSub in the United States runs a similar sequence of pool tasks, with weight bonuses and penalties, a diver-operated kill switch, and a task that uses hydrophones to find an acoustic pinger.

Rules change every year, so treat these as a starting point and design to the current rulebook. The vehicle below is aimed at the SAUVC bonus size and weight.

The vehicle

• One hull. A 165 mm clear acrylic tube, 400 mm long, holding the computers, the battery and a forward camera behind a flat clear cap. It displaces about 8.5 litres, so it can hold up the thrusters, frame and ballast of a vehicle well under the bonus weight.
• Eight thrusters in ArduSub's vectored six-degree-of-freedom layout: four horizontal at 45° and four vertical. With eight the vehicle can hold itself level while it drops a ball or lines up on a flare. Six thrusters work if the budget is tight, provided you put the centre of gravity well below the centre of buoyancy so the vehicle rights itself.
• Two computers. A Raspberry Pi 4 with Blue Robotics' [Navigator](/products/navigator-flight-controller) runs ArduSub and keeps depth and attitude. A Jetson Orin Nano runs the cameras, the detectors and the mission, and sends ArduSub its commands over Ethernet.
• Two cameras. One looking forward from inside the hull, for the gate and the flares. One looking down from outside, for the drums.
• Switches on the end cap for the kill switch, mission select and start, so nobody has to open the hull at the poolside.

Thrusters and the current budget

The list uses Blu-Sub's [Z60E](/products/blu-thrust-z60e-500): 4 kgf forward at 24 V, 290 W at most, 245 g, with its speed controller built in, so the hull holds no ESC boards. Eight of them weigh under 2 kg. Order four clockwise and four counter-clockwise.

At full power eight Z60Es would draw 2,320 W, over 100 A from a 6S pack, which no pool task needs. Thrust rises roughly with the square of propeller speed and power with its cube. At 60% of full speed each thruster draws about 0.6³ = 22% of its power: eight together draw about 500 W, or 23 A. Each still gives about 1.4 kgf, so the four horizontal thrusters, angled at 45°, push forward with about 4 kgf. That is plenty for a vehicle of 15 to 20 kg moving at pool speeds. Limit the thruster outputs' range in ArduSub to hold that, and the vehicle stays within the 30 A power switch.

Battery. A 6S2P Li-ion pack of twelve 21700 cells, about 9,000 mAh and 194 Wh, fits under the tray in a 151 mm bore. A 15-minute run might average 150 W on the thrusters and 27 W on the electronics (Jetson, Pi, Navigator, cameras). Using 80% of the pack, that is about 50 minutes, three runs per charge with some margin. Measure the real draw in the test pool and correct the sum.

The kill switch, mission select and start

Every competition checks the kill switch before the vehicle goes in the water, so design it first.

• Kill switch. Blu-Sub's [M10 rotary on/off switch](/products/subsea-m10-rotary-onoff-switch) on the end cap drives a [MOS low-side switch board](/products/mos-low-side-switch-board) inside, which carries the vehicle's current. The rotary switch is rated for only 0.5 A, which is enough because it only drives the board's input. It latches, so it stays off once a diver turns it. Paint the knob or wrap it in bright tape. If your rulebook wants the thrusters killed while the computers keep running, give the thrusters their own switch board and switch.
• Mission select. A 4-position [rotary waveband switch](/products/subsea-m10-rotary-waveband-switch) picks which mission the vehicle runs: the full run, or only the gate or the drums while you test. Read it on GPIO pins.
• Start. A [tap switch](/products/subsea-m10-tap-switch) is momentary: it conducts only while pressed. The diver taps it to start the run, and the Jetson reads it on a GPIO pin.

Seeing and finding your way

Cameras. Blue Robotics' [Low-Light HD USB Camera](/products/low-light-hd-usb-camera) looks forward through the flat acrylic cap. A flat port narrows the field of view under water: a lens that sees 90° in air sees about 64°. Mount the camera close to the cap. The downward camera is Blu-Sub's [Blu-Vision 8MP USB camera](/products/blu-vision-video-camera), in its own 300 m aluminium housing with a 90° field of view in air. It sits outside the hull, looking straight down, and its cable passes through a gland penetrator.

Detection. Gates, flares and drums are strongly coloured, so colour thresholding in OpenCV finds many of them. A small trained model on the Jetson copes better with changing light and reflections off the pool floor. Record video on every test dive, because those clips are your training data.

Navigation. There is no GPS under water. Without a Doppler velocity log, which costs several lakh rupees, ArduSub can hold depth and attitude but cannot hold a position. The practical way to navigate is the way a diver would: hold depth and heading, drive forward until the camera sees the gate, then line up on what the camera sees. The Jetson drives the vehicle the way a pilot's gamepad would, sending MAVLink control messages while ArduSub holds depth.

Depth and leaks. Blu-Sub's [M10 depth sensor](/products/subsea-m10-depth-sensor-0-30bar) (MS5837-30BA on I2C, rated for 300 m) threads into the end cap and connects to the Navigator through a JST-GH to DF13 adapter. The [SOS leak sensor](/products/sos-leak-sensor) watches the bottom of the hull. If you want height above the floor as well, Blue Robotics' [Ping2](/products/ping2-sonar-altimeter-and-echosounder) echo sounder measures it.

The hull and the end cap

A 165 mm [acrylic tube](/products/subsea-enclosure-acrylic-pv) with an aluminium [flange](/products/subsea-aluminum-flange) at each end, a clear [acrylic end cap](/products/subsea-acrylic-end-cap) at the front and a 16-hole aluminium [end cap](/products/subsea-aluminum-end-cap) at the rear. Blu-Sub rates its 165 mm acrylic cap to 50 m and its acrylic tubes from 20 m upward, depending on size. That is far deeper than any competition pool. Add a [vent and vacuum plug](/products/subsea-m10-self-sealing-vent-vacuum-plug) for a vacuum test before each run.

Keep a tether for development. A pair of [Fathom-X boards](/products/fathom-x-tether-interface-board-pair) gives you Ethernet to the surface while you tune the controllers and debug the mission, and an [Ethernet switch](/products/ethernet-switch) inside joins the Pi, the Jetson and the Fathom-X board. Unplug the tether and seal its hole for competition runs.

For the thinking behind these choices, see our guides to buoyancy and ballast for AUVs, penetrators and connectors and depth sensors. A tethered vehicle built from the same parts is in our student ROV guide.

Sources.

• SAUVC 2026 tasks, pool, run time, weight and size limits, bonuses and kill-switch rule from the SAUVC 2026 rulebook (accessed 2026-09-23)
• RoboSub kill-switch and pinger requirements from the RoboSub 2026 team handbook (accessed 2026-09-23)
• Specifications of the Blu-Thrust Z60E, the Blu-Sub housing parts, switches, switch board, depth sensor and Blu-Vision camera from Blu-Sub's published specifications.
• Navigator features from Blue Robotics' Navigator page (accessed 2026-09-23)
• Thrust and power against propeller speed from the propeller affinity laws. Treat the figures here as estimates, and measure your own.

Published 23 September 2026. Last revised 25 September 2026. Corrections to sales@vebixautomation.com.

Ordering for a competition team?

Send us the rulebook limits, your hull size and your competition date. We will check that the hull, penetrators and switches work together and send a quotation your institute or sponsor can raise a purchase order against. Ask for a quote.