Hi guys, I would like to check if upgrading copper tether to fiber optic, will help with increasing bandwidth?
Does anyone try SVS-700BR Fiber Kit? SVS-700BR Fiber Kit - Seaview Systems
We currently use the Fiber Kit from Seaview Systems, and it works great. We actually bought our BlueROV2 directly from them with it preinstalled, as well as a 100m tether, a 600m tether, and a fiber reel. They’re very easy to work with and were very helpful with the process of setting up the ROV.
We have had some issues with it but that has more to do with the intense working conditions we put our unit through and the inherent fragility of fiber optics itself. Our main use is pipeline inspections for water intakes and they can get very tight and have a lot of things to catch on. On top of that some of the ones we inspect go well beyond the transmission limit of the Fathom X tether. The fiber tether is very strong for fiber optic but has its limitations. I’d recommend getting a fiber optic splicer and learning how to patch it yourself if you anticipate putting it in a situation that it will bend a lot. I think they’ve updated their kit since we purchased it with a fiber SFP to usb-c which is what currently use to communicate with the system. That’s an upgrade that I would have recommended so it’s good they improved that as well.
Overall, it’s a great piece of kit if you need to be able to get over the data transmission limit of the fathom x tether (I believe it’s around 300m) and want an easy-to-use, lightweight option.
Hi Randomgui22, thanks for the reply.
Actually I have a few questions about the Fiber Kit from Seaview Systems,
- Are Fiber Optic cable Fragile while used with the Bluerov2? Example, if the cable is pulled or bent during operation?
- Have you experienced any cable break or damage during normal use case?
- What transmission speed did you get when using the fiber optic setup?
Thanks!
I’m happy to answer any questions that you would have about it!
- The cables can be pretty fragile, but they are sturdy compared to normal fiber optic cables. I would say that it’s a solid enough system that, of the times I’ve broken it, the main reason has been human error.
- I have broken and repaired the tethers about 5 or 6 times in the hundred times or so I’ve used it. The first was under 6 inches of ice when the cable snagged on the ice. The second was on that same project when I snagged it on a welded pad eye when I was returning to the surface. Another incident was when the water plant I was working on turned on its intake pumps and sucked it into its intake screen. The ROV itself survived with no issues but the tether had actually torn itself where it was connected to the ROV.
- I’m not sure what the speed is off the top of my head, but it’s plenty to run 2 cameras and the Ping 360, so I imagine it’s comparable to the copper tether.
I will say that any damage is due to the condiitions we put the tether through. We do a lot of salvage/emergency work that makes for tight turns and tricky situations. Also, early on, we lowered it through the tether, but now we use a hook and long rope for lowering/recovery.
If you have any questions, please feel free to ask at any time.
Hi @Holiday -
I would expect fiber to offer far higher speeds, 100Mbit+ depending on the ethernet switch used in the vehicle!
It’s probably good to not lift the vehicle by this type of tether, but it should be able to take equivalent tension, as during operation tether drag and length will result in similar forces being applied!
Fiber optic definitely is ideal for super long range and high speed, but it is quite fragile compared to copper, and tougher to repair / splice.
@tony-white @Randomguy22 Thanks for information and it help alots. 
Hi everyone,
Great discussion — very helpful for those of us working with tethered systems in professional diving applications.
I have a follow-up question about the mechanical protection of the fiber termination itself. When splicing or terminating the fiber with an ST connector at the tether end, how do you protect the fusion point so it doesn’t become a vulnerability during operation?
Specifically:
- What strain relief method do you use at the connector entry point to prevent the fiber from bending or pulling at the fusion splice?
- Do you use any overmolding, heat-shrink reinforcement, or a protective boot over the ST connector?
- Has the connector termination itself ever been the failure point, or has damage always occurred along the tether cable?
Context: we’re evaluating this approach for a commercial diving umbilical (up to 200m), where the tether is subject to tension and occasional snagging. Any field experience would be greatly appreciated.
Thanks!
Apologies for the late reply, I’ve been on a long term project with little down time this week.
- The strain relief system that comes with the svs fiber kit is (I believe) a slingco amarid double loop cable grip and it is great. I like it so much that I’ve actually bought another one to use on the fathom tether I am setting up on our BlueROV2 instead of the thimble it comes with.
- When splicing the fibers I use a reinforced heat shrink with a metal bar that I then do another layer of heat shrink with the reinforcement that the cable has. Finally I do another larger heat shrink for extra protection. This whole section is typically in the cable grip section to give it even more reinforcement.
- I haven’t had any breaks on the connector termination but have started buying premade cables and using those ends for speed of repair. The damage usually occurs a few feet behind the ROV and I believe it’s mainly caused by getting snagged.
I will say that we bought the fiber unit for a very specific job (an 1800 foot water intake on a great lake). If you don’t need the length/data transmission speed it may be more hassle than a benefit. I’ve recently bought a 200m fathom tether and retrofitted our ROV to use that instead for smaller jobs. I kept all of the SVS Fiber system installed as well so all I’ll have to do is switch the ethernet cable (and power) inside of the system to switch between them. I plan to also connectorize the fathom tether with the Blue Trail Cobalt connectors after this next upcoming job I have.
Overall we’re very happy with the system, I’m just making it a little more “Diver-proof” if that makes sense.
I hope that helps!
Thank you so much for the detailed write-up — this is exactly the kind of hands-on experience that’s hard to find anywhere else.
Your strain-relief approach really clicks for me: letting the aramid grip and the layered heat shrink carry the mechanical load, with the splice sitting inside the grip, so the fiber and connector never take any strain themselves. And your point that fiber is more hassle than benefit unless you actually need the length and data rate lines up exactly with the direction I’ve taken with Fathom.
Really appreciate you taking the time to share all this. Thanks again!