Just ordered my FATHOM!

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Doby45

Do I have something in my teeth?
Scuba Instructor
Messages
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Location
Acworth, GA
It is time for me to step into the sweet sweet world of rebreather diving. I look forward to changing the whole way I dive and losing the "PSI Clock" from my diving. I will post a bit as I progress down this rabbit hole. WOOT WOOT
 
It is time for me to step into the sweet sweet world of rebreather diving. I look forward to changing the whole way I dive and losing the "PSI Clock" from my diving. I will post a bit as I progress down this rabbit hole. WOOT WOOT
Is this your first unit?
 
Fathom is a great unit. Enjoy!

That needle valve life is the way to go.
 
Congrats. My wife and I took our class in December. We love the units. They're super simple and rubust. The first 20 hours or so kind of suck. Managing loop volume as well as your wing and suit can be a pain. You will have great days, and then the very crappy days for a while. We did alot of very shallow 25ft or less dives to get used to managing everything. Swimming in the main spring at Ginnie at 15 ft can be very annoying, especially when you need to go over a log. Just 3 ft difference can make a big change in buoyancy. 20 hours or so in and I still hold my breath or exhale hard to adjust buoyancy, then 3 seconds later realixe how stupid I am.
Did you go with a BOV or no BOV? We went with the divesoft BOV and love it. I did find that we had to lengthen one hose because with a bov it made the hose bend right at the fitting and left a bulge in the rubber that made me think it wouldn't have a very long life. Only other thing I did was change from 3L steels to al30s (the third one from the left on the link below). It's not a big deal, but with steel 3Ls the unit sits back and on unstable benches or rocky areas with no bench it didn't always feel the most stable. The al30s are the exact same length as the 3L, and have similar weight and buoyancy characteristics (negligible differences), but make the unit stand up straight. The only negative is that it can be a little easier getting into the harness with the 3L since it leans back, but again negligibly. The al30s also hold significantly more gas
Small Aluminum Cylinders, Brushed No-Coat

Once you're done with your training if you want to get some OW dives in at any of the springs I'd be happy to dive if I'm free. We've been doing some pretty basic cave dives on our units at this point, but am happy to build hours outside of the caves.
 
Congrats. My wife and I took our class in December. We love the units. They're super simple and rubust. The first 20 hours or so kind of suck. Managing loop volume as well as your wing and suit can be a pain. You will have great days, and then the very crappy days for a while. We did alot of very shallow 25ft or less dives to get used to managing everything. Swimming in the main spring at Ginnie at 15 ft can be very annoying, especially when you need to go over a log. Just 3 ft difference can make a big change in buoyancy. 20 hours or so in and I still hold my breath or exhale hard to adjust buoyancy, then 3 seconds later realixe how stupid I am.
Did you go with a BOV or no BOV? We went with the divesoft BOV and love it. I did find that we had to lengthen one hose because with a bov it made the hose bend right at the fitting and left a bulge in the rubber that made me think it wouldn't have a very long life. Only other thing I did was change from 3L steels to al30s (the third one from the left on the link below). It's not a big deal, but with steel 3Ls the unit sits back and on unstable benches or rocky areas with no bench it didn't always feel the most stable. The al30s are the exact same length as the 3L, and have similar weight and buoyancy characteristics (negligible differences), but make the unit stand up straight. The only negative is that it can be a little easier getting into the harness with the 3L since it leans back, but again negligibly. The al30s also hold significantly more gas
Small Aluminum Cylinders, Brushed No-Coat

Once you're done with your training if you want to get some OW dives in at any of the springs I'd be happy to dive if I'm free. We've been doing some pretty basic cave dives on our units at this point, but am happy to build hours outside of the caves.

I did go with the Shrimp BOV and I also am going with AL30s, just made sense to me. 3Ls are 3442 and you don't always get an O2 fill at 3442. 3k fill is far more common and with the AL30 you get a ton more O2. I have also heard the same about the first 20-30hrs being a bit trying, so I hope I pick it up pretty quick. My plan for now is to roll HP100s for bail out. I will absolutely keep you in mind when I am down for some dives. Cave is the end goal for me as well and was part of the reason for the decision. As I said earlier, I am very excited to be looking at a stack timer instead of a bottles thirds.
 
I don't know anyone filling O2 over 3K. But a 3L at 3000psi is about 19cf aka 3L x 200bar = 600L. Which is about 7 or more hrs of O2 depending on the ups and downs. I think you're good for awhile either way lol.

Hp100s of BO? That would be an unusual choice. Lp50s are really dreamy to dive. They also make buoyancy easier since the mass of gas requires a smaller bubble in the first place. If nothing else you should try them, with cave fills its plenty of gas for decent penetrations at the usual tourist caves.
 
Just curious what the typical/default IP is set at with a fathom?
I have Charlie's needle valve and I blocked mine at 200psi.
 
I did go with the Shrimp BOV and I also am going with AL30s, just made sense to me. 3Ls are 3442 and you don't always get an O2 fill at 3442. 3k fill is far more common and with the AL30 you get a ton more O2. I have also heard the same about the first 20-30hrs being a bit trying, so I hope I pick it up pretty quick. My plan for now is to roll HP100s for bail out. I will absolutely keep you in mind when I am down for some dives. Cave is the end goal for me as well and was part of the reason for the decision. As I said earlier, I am very excited to be looking at a stack timer instead of a bottles thirds.
Try the 3L too. My wife personally likes them over the al30s. I like the 30s better. You can't go wrong with the shrimp or the divesoft bov. I went with divesoft because my instructor prefers them and a plus is divesoft's US repair center is 15 minutes from both my work and house. I originalyl was leaning towards the shrimp because there were a few issues with the divesofts that have since been resolved.
I do 50s or Faber 85s for BO. I've always dove worthington 85s, so I'm currently enjoying being spoiled carrying the light 50s. I went with the dive rite rec wing since it's a small form factor and I'm not sure it would be enough for worthingtons and a stage, though it's perfectly fine for the fabers.

I don't know anyone filling O2 over 3K. But a 3L at 3000psi is about 19cf aka 3L x 200bar = 600L. Which is about 7 or more hrs of O2 depending on the ups and downs. I think you're good for awhile either way lol.

Hp100s of BO? That would be an unusual choice. Lp50s are really dreamy to dive. They also make buoyancy easier since the mass of gas requires a smaller bubble in the first place. If nothing else you should try them, with cave fills its plenty of gas for decent penetrations at the usual tourist caves.
I had my stell 3L filled to 3800psi by a popular cave country shop a couple weeks ago. that's a cold 388, so I suspect it got all the way to 4k while on the booster. I think it was a matter of a lazy shop employee not paying attention.
I like the 50s too for regular, shallow cave dives, but have 85s setup for longer penetrations or deeper dives. The biggest issue to me for the 50s is they were a little harder to setup and get used to. I set them up how I normally would for a steel sm tank and they sat really funny. I think because they're lighter and smaller diameter the torquing forces between the bungee and the leash are exacerbated. I usually dive regs up. With the 50s I found they kept wanting to roll in. In the end I decided to wrap the bungee around the manifold nipple as opposed to the valve and adopted a regs into armpits/chest configuration. Otherwise with the valve up the bungee was either too loose, or rolled the tank too much.

Just curious what the typical/default IP is set at with a fathom?
I have Charlie's needle valve and I blocked mine at 200psi.

The checklist says 205-230psi, though both of ours are at 190. I chalk it up to a crappy analog ip gauge and don't think being under 200 matters
 
There's also a Fathom user's FB group. The only issue is nobody ever posts. Wish that would change.
 

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