Flexible Underwater Ribbon Cable Guide

 The previous rigid 3-D printed shell that was used to join the underwater WeatherBox to the main electronics box on the AMOS surfboard needed to be replaced with something flexible that could flex and swing out of the way whenever underwater obstacles were encountered. 

Some inexpensive plastic tubing was purchased at Home Depot, and 3-D printed adapter parts were constructed for either end of the tubing, to join it to the WeatherBox at the bottom end and the main electronics enclosure at the top end. 

This made a nice, water-tight conduit for the camera cable to follow, but it proved to be difficult to design the top piece to be strong enough to withstand large bending moments that were produced whenever AMOS passed over a shallow, rocky area. Three different top-piece designs were fractured in separate field tests before switching to a slightly different design using a large cable gland at the top. Instead of fitting the top end of the tube over a 3-D printed male plastic piece, the top end of the tube was fitted inside the cable gland. A small amount of heat treatment with a heat gun was applied at the top end of the tube to allow it to compress slightly and ensure a snug fit. 

This design worked perfectly: it had enough "flex" to be able to swing up out of the way of obstacles, without putting too much stress at the top cable gland connection. Here is a video of AMOS crashing into an underwater rock. The WeatherBox and its cable guide swung out of the way and were undamaged:

I enjoy combing through the videos from these tests, looking for fish. Here were a couple that were briefly captured in the most recent test yesterday (October 6):

My favorite clip came at the end of the test when AMOS was just floating near a partially submerged tree. I really like how the light from the sun is shining on the tree in this video, it looks kind of magical: