Hi,
My organization Aqualink, a philanthropic engineering organization working on Ocean conservation problems, is publishing the full source code and build instructions for an ASV. It’s built with off the shelf parts (including BlueRobotics thrusters), Pixhawk, ROS, NVidia Jetson, and Zed stereo camera. The instructions are pretty detailed and if you provide a hull you should be able to build your own ASV for under $2,500.
Check it out at Aqualink
Thanks,
Pete.