Water in E-Tube


I took my OpenROV out for its first flight today. It was fine for the first few runs, but one run ended up with water in the E-Tube as well as battery tubes. Is there some procedure that should be followed to avoid too much damage?



If it is salt water, Rinse your batteries with fresh water ASAP. Sooner is better. Towel them off and put them somewhere safe to dry. Don’t heat them up though.

Same with electronics, after removing from power (which happens when you unplug from the endcap) though there are more steps you can follow involving rice (or other) to draw moisture away (though I am not familiar with them). If salt water only touches the e-chassis but not the electronics, you probably should rinse it all down any way. If salt is in the tube, it can eventually get moved around (from condensation etc) and give you trouble down the road.


Thank you. It was a test run in a swimming pool, so not salt water. I think we will just have to use rice.


If it is fresh water, you can probably just let it dry with some added heat. :slight_smile: But don’t let me stop you from doing it the correct way!. I am lazy. :smiley:


Pool water is usually not a big problem dealing with. However, depending on the amount of pool chemicals added it can be somewhat corrosive. I’d say towel dry, put in container with dry rice for a day or to to help absorb any residual moisture. I would avoid applying any electrical charge to the components until you are reasonably sure all of the moisture is gone. Then (very important) determine how the water got in and figure out how to prevent it in the future.


If the e- tube end caps don’t have a good seal, you can try putting an elastic band or slice of balloon (cut so you have a loop, like an elastic band) underneath the o-ring. The trick is to pick the one that adds the right amount of thickness. Too thick could make it impossible to close.

For the battery tube end caps I used hair elastics. The ones that are slippery so they don’t pull out hair. I used them because they were small, but they do squish down after a bit, so you can either replace them from time to time, or perhaps leave your end caps out when you are not ROVing.

You can also try wedging something into the sides of the o-ring. Maybe an elastic! This was suggested to me by evilmacaw. He said it makes the o-ring stand “proud”.

Here is the forum topic if you want to see pictures of how to use a balloon.


Did your end caps come off in the water?


The end caps did not physically come off. They seemed intact, but I did not account for the expansion of nylon in water. I think this caused the straps to loosen enough to let a little water into the E-Tube and battery tubes.

Update: All the electronics are functioning as expected.