Losing Propellers, Finding Replacements

propulsion

#1

Over the course of my last two dives, I lost two propellers!!! ((I have a ‘very low mileage’ OpenROV 2.8))

First, I lost the vertical prop, because (I think) the motor bell was not properly seated in the mount when I built the ROV. When I went to descend, the motor popped out, wedged in the chassis, and the motor unscrewed the propeller. So, I ordered a prop kit from OpenROV. I also got a temporary R/C boat propeller from the local hobby shop that’s sold as a replacement for the “Aquacraft Reef Racer”, to hold me over until the real ones came. Unfortunately, the temporary propeller is way too small, generating barely enough force to push the ROV under the surface :thumbsdown: .

I lost the second propeller while driving my ROV around on the surface and testing the small vertical propeller. I really don’t know what happened–it just unscrewed itself while I was playing with it on speed ‘4’. Has anyone else had this problem? From now on, I’m tightening the crap outta those props before every dive. Alternatively, I’m thinking of using some locktite on the replacement props to keep this from happening again–Good idea?

And as luck would have it, OpenROV is waiting on a backorder of prop sets before they can ship me my replacements :frowning:. Things are warming up here, the water is clearing up, the fish are starting to spawn, and I am extremely anxious to get my ROV up and running again! ASAP. Has anyone found any suitable alternatives to the Graupner props that OpenROV re-threads and sells? I’ve scoured the web, and can’t find anybody in the USA that sells anything similar to these propellers. Amazon has a lot of options, but very few details on them. The R/C boat prop that I got came with drive dogs that fit the M3 shafts, so I’d imagine that opens up some options…

Thanks!


#2

The best source for Graupner props is Cornwall Model Boats in the UK. They have the OpenROV props in stock, though they will have an M4 thread, so you have to epoxy them onto the motor shaft similar to what was done on OpenROV prior to version 2.7. Check out the Dozuki guide for building OROV 2.6 to see what is involved.

There are links to Cornwall Model Boats on the OpenROV BOM as a second-source. Note that they also carry the vertical prop (2303.57), in their selection of racing props.

-Walt


#3

BTW, I use Loctite on my props, but the real answer is to make sure that they are properly tightened in the first place. The Dozuki instructions are not kidding when they tell you to “very snugly” tighten both the propeller and the jam nut.