Hackaday reported on the Nanoseeker:
The Nanoseeker is a compact underwater vehicle in a torpedo-like form factor. [John] designed the Nanoseeker as completely enclosed vehicle: both the thruster and the control fins are all housed within the diameter of the tube. The thruster is ducted with vents on the sides and control fins integrated into the back of the duct assembly.
[John] designed a compact PCB to drive the vehicle, which includes an STM32F4 alongside several sensors. An MPU-9150 provides IMU functionality and two dual motor driver ICs from TI control the throttle and the control fins. [John] also added a Bluetooth radio for remote control functionality. For those who want a closer look, an image of the schematic is up on his blog.
Looks like a cool design - excited to seeing this one in the water. I'm seeing more and more 3D printed underwater designs.