In the process of cleaning the thrusters from hagfish slime, I noticed that one of the thrusters looked uneaven and with holes in the coating. The other five thrusters did not look like this. Is this normal?
That coating definitely does not look normal! It looks like it was scraped off by some debris that likely got caught inside the thruster, between the rotor and stator. Without the coating, the magnets can start corroding quickly, so it is strongly recommended to replace the rotor. We have spare rotors available here.
Hagfish slime sounds like a nightmare to clean out of everywhere! Luckily, we haven’t had a run in with any yet during our dives of the California coast.
The stator looks fine, what I find odd is that the surface looks bumpy, not smooth. Do you assemble the motors and check the quality or could there be some kind of error from the manufacturer?
Yes hagfish slime is a nightmare and makes the ROV smell very badly
Yes, we do test and assemble every thruster ourselves at Blue Robotics. We are constantly improving the coating and plan on making it more abrasion resistant and tolerant to these sort of situations in the future, but currently certain debris can cause this sort of damage. The current coating on the stator is more abrasion resistant, so visual evidence of the scraping may not be present there.
I just removed the propeller and found more corrosion. To me it looks like defective coating. I do not see how this should be caused by physical damage.