FATHOM Dive Systems Q&A

[kensuf]

I bought my fathom with an adv. I pulled it off after a year and don't see any reason to put it back on. Grant is correct.

 

[rddvet]

For wreck diving with either hot drop or pulling down the shot line does anybody who dives with BOV have an ADV? Is this configuration possible from Fathom or would it require a different MAV with 3 ports. I saw that dive soft has BOV with built in ADV but don't know if this is good option.
Thanks

You need a hand for your drysuit inflate or (for some) ears anyway, so the MAV on a hot drop isn’t an issue. That said, you can very slightly crack the BOV to get the same effect. I don’t think there are more than a few fathoms with a BOV and an ADV, as most people either go BOV or DSV+ADV and I think that’s probably a 20:1 or 30:1 ratio.

Edit: once upon a time I think @rddvet had the divesoft BOV on his or his wife’s unit and can probably chime in

I have the adv on my unit. I actually like it. I think most of the instructors now don’t recommend them as it adds a failure point. I’m on an early unit (#15) so I took the course as one of the first my instructor taught. At the time he was pro adv. he’s since changed his mind. I like the adv for the reasons you mentioned. I don’t hot drop but I will scooter into a cave with some speed. The adv isn’t necessary but nice. My wife had the diaphragm on hers tear. But otherwise the adv Charlie uses is pretty good compared to any other I’ve tried. That being said if my adv ever fails I’m replacing it and going without one.

My wife and I dive divesoft bovs. I prefer them to the golem ones as I think they’re more comfortable and better quality. I have also been strongly against anything golem because historically the customer service was awful. They’ve changed hands so that’s not an issue anymore. I have yet to meet someone who loves the divesoft that has the bov. I would skip and if you want a bov go with the one Charlie uses

 

[barkandlink]

I have the adv on my unit. I actually like it. I think most of the instructors now don’t recommend them as it adds a failure point. I’m on an early unit (#15) so I took the course as one of the first my instructor taught. At the time he was pro adv. he’s since changed his mind. I like the adv for the reasons you mentioned. I don’t hot drop but I will scooter into a cave with some speed. The adv isn’t necessary but nice. My wife had the diaphragm on hers tear. But otherwise the adv Charlie uses is pretty good compared to any other I’ve tried. That being said if my adv ever fails I’m replacing it and going without one.

My wife and I dive divesoft bovs. I prefer them to the golem ones as I think they’re more comfortable and better quality. I have also been strongly against anything golem because historically the customer service was awful. They’ve changed hands so that’s not an issue anymore. I have yet to meet someone who loves the divesoft that has the bov. I would skip and if you want a bov go with the one Charlie uses

How do you have the adv set up? Does your mav have 3 outlets (mav,bov, and adv) or do you have bov/adv from divesoft?
Thanks

 

[rddvet]

How do you have the adv set up? Does your mav have 3 outlets (mav,bov, and adv) or do you have bov/adv from divesoft?
Thanks

ADV is at the t piece on the left shoulder. The dil mav has a qc6 at the bottom for offboard dil, that goes into the mav which has two outlets. One outlet is controlled by the mav button the other is a bypass. On the bypass side theres a small hose leading to a splitter. One side of the splitter goes straight to the bov, the other has a flow stop that goes to the attachment on the adv. I just have the regular divesoft bov. I've attached a picture of the mav/hoses to bov and adv. In the photo it looks a little clunky, but it is no way is. I was worried about the splitter being a failure point, but 4 years or so down the line not a single issue.

 

[211ratsbud]

ADV is at the t piece on the left shoulder. The dil mav has a qc6 at the bottom for offboard dil, that goes into the mav which has two outlets. One outlet is controlled by the mav button the other is a bypass. On the bypass side theres a small hose leading to a splitter. One side of the splitter goes straight to the bov, the other has a flow stop that goes to the attachment on the adv. I just have the regular divesoft bov. I've attached a picture of the mav/hoses to bov and adv. In the photo it looks a little clunky, but it is no way is. I was worried about the splitter being a failure point, but 4 years or so down the line not a single issue.

View attachment 790168

Don't mind the mess kids are like tasmanian devils around here. This mav would simplify some I believe

 

[rjack321]

ADV is at the t piece on the left shoulder. The dil mav has a qc6 at the bottom for offboard dil, that goes into the mav which has two outlets. One outlet is controlled by the mav button the other is a bypass. On the bypass side theres a small hose leading to a splitter. One side of the splitter goes straight to the bov, the other has a flow stop that goes to the attachment on the adv. I just have the regular divesoft bov. I've attached a picture of the mav/hoses to bov and adv. In the photo it looks a little clunky, but it is no way is. I was worried about the splitter being a failure point, but 4 years or so down the line not a single issue.

View attachment 790168

Never been a fan of the dil mav, the adv, and the bov all fed from the same qc6. If, for instance, either the bov hose, or the hose up to the Y manifold were to fail - that takes out all your dil options and more.

I run my BOV off the left SM cylinder, my dil and ADV off the right SM cylinder. Separate feeds via separate QC6s. Wing and suit gas are similarly split.

 

[rddvet]

View attachment 790262


Don't mind the mess kids are like tasmanian devils around here. This mav would simplify some I believe

That wouldn't be any cleaner and likely less clean. The short hose going to the splitter is actually nice because once it splits off its under your loop and high on your shoulder so you don't really notice it. I think with 3 separate hoses it would be a little more cluttered coming off the mav, but probably not super significant. I also wouldn't want to have a mav button thats not seated below the mav body. I dove a unit with the button sticking out like that and it would every once in a while get bumped. The stock mavs on the fathom are pretty hard to beat. 4-5 years in I've never had to service any of the mavs and the only unit issue we've had is my wife ripped the adv diaphragm by doing a head down scooter descent with the adv off and also a wire in her hud went bad. All fixed quicly and under warranty by Fathom.

 

[rddvet]

Never been a fan of the dil mav, the adv, and the bov all fed from the same qc6. If, for instance, either the bov hose, or the hose up to the Y manifold were to fail - that takes out all your dil options and more.

I run my BOV off the left SM cylinder, my dil and ADV off the right SM cylinder. Separate feeds via separate QC6s. Wing and suit gas are similarly split.

It doesn't bother me. At that point I would just bail to an offboard sm dil reg or to the long hose if diving in the tec configuration.
I absolutely see your point and it makes sense. It just is a calculated risk of the unit that doesn't really concern me. Any unit will have its problematic idiosyncracies. If that's the only one I can find on the fathom, then I'm doing pretty good.

 

[rjack321]

It doesn't bother me. At that point I would just bail to an offboard sm dil reg or to the long hose if diving in the tec configuration.
I absolutely see your point and it makes sense. It just is a calculated risk of the unit that doesn't really concern me. Any unit will have its problematic idiosyncracies. If that's the only one I can find on the fathom, then I'm doing pretty good.

Oh I get the alternative. 2x QC6s is a pita and twice as much to poop out.

The one and only time I had a failure in a SM tank was actually the HP hose split. Not massive gas loss but the bubbles were crazy annoying. I was grateful to be able to shut it down and plug in the opposite side QC6. So I had wing & dil but no more BOV.

 

[SavageSeaCow]

Hi everyone, I wanted to open up this forum to act as a Q&A for Charlie Roberson and I (Matt Key) for questions involving our rebreathers.
We want to make ourselves available within the ScubaBoard Community, and answering any questions you may have involving our design, philosophy, or anything else related to our rebreather lineup.

In addition to our record-breaking Fathom MK3, we are very excited to announce that our rebreather offerings are expanding this year with our new FATHOM GEMINI. Utilizing our needle valve, line lock system, HUD, potted electronics, and removable scrubber in a form factor that is great for squeezing into small caves, or throwing into a carry-on for your next vacation. While none of these features may be "new", offering all of them in this layout and form factor certainly is.


We look forward to your questions and hearing from this community.

I have a question actually regarding the dual MAV/needle valve set up. I’ve seen the pictures on the fathom website but I’m wondering what each port is and if it would work as a retrofit to a non fathom rebreather. Is it possible to route the dill and O2 both from the top? Also if I were to upgrade my regulator/spring can you recommend a source for the higher pressure LP hoses?