A reel way to manage your tether!


Recently at OpenROV we have noticed that although the current tether management system is sufficient and simple to build, it is a little cumbersome to use especially when you are using large amounts of tether. This thus inspired us to build a simple, low cost tether management solution that could fit in the box with the ROV during transport.

The design is made mostly from acrylic and is comprised of two main parts; an outer, non-rotating, reel that contains a slip ring and mounting points for a belt clip and an adjustable camera tripod, and a inner rotating reel in which the tether physically wraps around plus an handle for easy rotation

(The outer reel with the slip ring)

(the CAD model of the inner reel)

One of the big questions which we are not sure on is what type of mounting system is most optimal for the reel. Do most people want to wear the tether on their belt or mounted to the floor or a pole? Because of this we opted to have the reel try to capture best of both worlds by having built in screws intended to mount to a belt clip as well as a 10-24 nut which is the standard size bolt used on camera tripods. Our initial thoughts were using a flexible “octopus style” tripod because of their versatility to attach to multiple surfaces, yet a more rigid style tripod could be better for different situations.

(the backside of the outer reel, the 10-24 nut is intended to mount to a camera tripod, and the four machine screws attach to a belt clip)

(an "octopus style" camera tripod holding up the reel)

Let me know what your thoughts are or what other tether management systems you have come up with. I'll post the CAD files on the github soon.

Additionally a parts list is attached below.


319-PartsList.docx (18.8 KB)


Looks great. First thought is to make the outer/stationary rings hexagon or octagon so it could just set on a table. is the cad file for this available?




That's a very clever idea! At the very least I could flatten one side to give it a natural platform to rest on. I was hesitant at first to put a large "right angle type" stand on it, but using the given structure of the reel as the stand seems like a great compromise between the two. My only worry about flattening one side of the reel and using that as stand is that it would not have enough surface area to rest on be stable, but I guess the only way to figure that out is though experimentation.


This looks awesome! Great work!


I'll post CAD files on the github later this week. I have to fix a couple of drawings.


Awesome! Putting the mounting point for a tripod is a great idea. Many people will already have one. I think using a "full sized" tripod might be convenient. I hate that I always have to crouch down to deal with the tether. :D

I will build this when you put the plans up.

Great work and thanks for making this. :D


This looks awesome! I was eyeing up one of my empty filament spools from my Makerbot and hacking that for my tether management system.

Were you able to store the full roll of wire that ships with the kit on your design?



I was able to fit the entire 100 meter tether on the reel no problem. Its hard for me to tell the exact size of your filament reel, but it looks like it might fit. The reel I designed has an outisde diameter of 154mm with a width of 62 mm, you could thus calculate this volume and subtract out the area of the center axle which as a diameter of 31mm. You could then compare this area to your reel to see if it could take all 100 meters of tether. Hope this helps.


Hi Patrick,

Really great stuff! Were you able to post the CAD files to github? I’d like to make this reel for my openROV as part of a class project this week :).



I just attached them to this post. Thanks for the reminder! It’s current a .zip file, so don’t forget to unzip it.

dxf.zip (266.1 KB)
Inventor Files.zip (1.2 MB)


Thanks for the quick reply! These are very helpful!


Hey, this is great! Have you tested the slip ring? Do you think the connection is as stable?


Hey Robert. I use the Adafruit slip ring in a modified cable reel and , so far, no issues at all. It has 6 wires so having 3 fingers to each tether wire means even if you get a tiny jump or miss, one one finger, it’s not going to crash the connection. This is mine with 100 metres of tether inside poly rope.


Very nice! I hadn’t considered the three pins per wire idea. That’s awesome. I will be borrowing that. Thanks!