(EDIT, Jan. 07, 2021: For more info on AMOS and In Nature Robotics, please also visit https://www.innaturerobotics.com/)
It pained me somewhat to carve up a brand new surfboard fresh out of the box, but I used the two AMOS electronics boxes as guides to carve out rectangular holes in the bow and stern and then wedged the boxes in. The fit was pretty snug, so I didn't bother gluing anything down:
This last video showed a bit of a problem that the compass was having with giving accurate heading when the boat should have been moving south. The compass error must have been pointed towards the southeast, because the boat would start in that direction, realize that the new target direction was southwest (or even west) to get to the next waypoint, and then move in a big curve to correct for the initial path error. The temperature in the electronics box started off at 8 degrees C at the start of the test, and fell to 3 degrees C by the end. The magnetometer calibration was done at -3 degrees C, so that might have been a source of error. And probably there was some error from the Z-axis (vertical) magnetometer on the compass, since it had never been calibrated on this unit, and the new inclined angle of the bow on this boat would have caused that magnetometer to come more into play for determining heading.