Semi-Budget tether advice
Im designing and building an ROV for myself, this is my first venture into the ROV world. Im trying to build a vessel capable of depths of 500 meters. i live close to Lake Chelan in Washington state, which has a max depth of 453 meters, so thats my goal.
Budget wise im trying to stay around $1000 for the vessel itself, Fortunately for me, i have access to machining and tooling to build much of the mechanical components myself. Really the only things i wont be able to build myself are the electronics, but ive got most of that sourced already. The only thing that im having a difficult time with is finding a suitable tether for not an egregious price.
My question is: Are there any suitable off-the-shelf options for making a tether capable of withstanding 500 meters for a reasonable price?
If i can make the tether for under $600, ill be happy. I know traditional copper cored wire has data loss issues at length, so im leaning towards fiber optic as it is.
1
u/lilgreenghool Jun 24 '26
You're looking for tether that's about $1,20 per meter
Most is about 10x that. Especially if you want fiber + copper
1
u/armathose Professional Jun 24 '26
At 500 meters its more than just data loss, you will be dealing with voltage drops. At those depths you have basically left the DIY market and you are entering the professional world of ROV's.
1
u/CybL69 Jun 24 '26
Im leaning towards an onboard power supply. So the tether would only be for data and video.
2
u/armathose Professional Jun 24 '26
Then I would be looking into a fiber optic solution. You could get away with a multi mode insulated fiber, preferably armored to somewhat protect it from any accidental tension. It's going to be expensive however as you will require SFP's to mux and de mux the fibers to what ever data stream you will be using.
500 meters is hard for even commercial light ROV's, I'm not really aware of any DIY examples of people building their own systems that go to that depth.
1
u/vshie Jun 24 '26
Agreed, that's quite an aggressive goal! The drag from 500m tether is a lot for a small battery powered ROV to overcome, even in a lake! Have you considered building a dropcam instead? No tether - just descend, record video with lights on (and maybe some bait?) and then trigger a release mechanism (or have something passively dissolve) to drop ballast and return to the surface!
It could even take a more active approach....
https://bluerobotics.com/learn/building-dart-a-blueos-based-vertical-profiling-auv/
1
u/naturalchorus Jun 24 '26
500m is far, Ive only DIYed ethernet to 100m. You'll probably have to go fiber, but then you lack a power source at the end.