Slip ring robustness

Hi there,

Just back from a field trip using our new Fathom Spool, where we had a few issues with the connection from the slip ring (to the control box).

Essentially, in a bit of chop on a small boat we ended up catching/tripping up on the reel-interface box connection, which dislodged it (plus we broke a couple of wires to boot while trying to screw it back in to the reel).

I was wondering two things. First, could that connection be made more robust -now it’s out we can see it’s a not especially strong looking plastic thread? Are there any other suggestions about how to avoid a similar problem in future (other than tether management!)? The reality is a lot of our work is going to be on a small, moving boat, so making things tough as possible is key.

Second, is it possible to get hold of a spare slip ring? We’ll repair the one we have, but on a remote field trip like we were we would have had a better chance of rebuilding the spool with a new ring than trying to re-solder connections (I’m a biologist so while I can work a screwdriver OK, fine soldering is not my forte!). In this case, a spare ring might have let us keep going the next day using the spool.



Craig, you’ve encountered exactly what I was worried about myself with the reel. The plug and interface cable are vulnerable and present a single point of failure that could easily end a trip, and a small boat is a tough environment for anything that’s not extra robust.

My solution (not yet complete) will probably be to install a ring guard around the plug made from a 3" ABS pipe end cap attached to the frame. The interface cable will have strain relief using a thimble which will be clipped to the ring guard.

Hi Craig,

Bummer! I’m sorry you had trouble with this. We haven’t seen this happen yet but I can see how the connection would be vulnerable in rough conditions.

The slip ring and connectors are all assembled in a specific order and can’t be removed from the aluminum parts, but we can get you a replacement/spare of that whole assembly. If you’d like to do that, can you shoot us an email at and we’ll figure that out.

In the meantime, I’d suggest possibly securing the 8m extension cable to the side of the spool with zip ties or something so that if someone trips on it it pulls on the whole spool and not just the connector.



Thanks Rusty, Tim

Yep, small boats can sometimes be quite tough working environments.

In future we’ll try to provide some strain relief with some cable ties - but I also like Tim’s idea about trying to attach some sort of cap assembly around the plug itself, as a way to minimise the effects of any direct knocks. Something that screws on/off for transport would be ideal.

I also want to add that despite this hiccup, we really do like the spool as it makes tether management a whole lot easier, especially on a small boat.



I have just had the exact same issue. Love the spool but very weak plastic threaded insert spoolside. There is also no workaround so any ROV work has to stop until the spool is repaired. There is a lot of leverage available on the plug and tether sticking out of the spool. A cap or cage is needed to protect the plug from any sideways knock.

In case that happens again and it’s not fully destroyed like in the first post from last year, don’t try to fully repair it. Just get it working by either resoldering, or cut off the connector and solder direct to the deck cable, or even just twist the wires together if you have to, and zip-tie everything to the leg on the side of the spool as a strain relief until you get time to repair it proper. Don’t try to screw it back in because it will cause more problems.

When you do go to repair it, that broken end is soldered/installed first, but it’s all pretty self-explanatory when you’re holding the slipring assembly and you remove everything. The two halves of the slipring pull apart by hand. Normally, you may need to push the center of the Binder bulkhead to allow air in, otherwise you’re pulling on a vacuum when you pull the two halves apart, but they should pull right apart with a broken one, just a little o-ring resistance for the weather sealing. Do it carefully so you don’t rip in half like a gorilla, because you’ll want to see how the wires lay inside.

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Same for me, on a boat that moves … I am looking for the color wiring scheme (not the same colors as on the Binder/tether!!) to reweld in the right place !!

now it’s strong !!


Does anyone know the pinout for the slipring to the external connector? We have also encountered this problem. @JeanBenoit are you able to share the design of your modification?


Hi Marcus,

I asked internally and was sent the following image.

I’ll try to get some clearer details on it and add it to the technical details tomorrow. If you need more info/clarification I’ll try to sort that out tomorrow too :slight_smile:

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ok thanks, it would also be good to know the best way to disassemble the slip ring. For example, can the external Binder connector simply be unscrewed? I want to install a protective shroud on future units, so will need to remove the Binder plug, even on units that are not already damaged.


I’ve been told it should be able to be unscrewed, with some care taken not to damage the slip ring wires. Note that it might be a bit challenging to get the wires back in when re-installing it.

This is our cage. It can be assembled with a cable gland for permanent attachment of the extension cable, or with a Binder bulkhead allowing the extension to be disconnected. Let me know if you’d like the STL

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