80 CF Aluminum as Pony Bottle?

[redacted]

problem with 13's is they aren't really useful beyond 60ft for a safe ascent. If you have a 13cf bottle at 100ft it's going to be dry before you hit the top if you're ascending at the right rate and you sure won't have any chance of a safety stop on that thing. Not to bash your decision or anything, but make sure you're doing the actual calculations to see how long that thing is actually going to last you before you rely on it.

80's are fine as pony's, we carry them as stages all the time. Little overkill, but if you're going to that effort, it's easier to just dive sidemount with a pair of 80's for the pretty fish diving and call it good.

That would depend on cosumption rate. I have run an ascent on 13 cu ft pony from 85 ft with a very slow ascent and a 5 minute safety stop with gas to spare.

 

[tbone1004]

obviously, but using a 13cf as pony at 100ft is still planning for the best, hoping for the best. I've never understood why people travel with their pony bottles, when an 80 can be slung quite easily and unobtrusively on a BP/W and used as a stage. Put a sidemount bungee on the side of the plate and it tucks in real well. better yet, build a razor style rig for under $200 and just dive twin tank sidemount and use something that packs in a stuff sack with regulators....

[video=youtube;M6uqtFJaNpA]https://www.youtube.com/watch?v=M6uqtFJaNpA&index=8&list=WL[/video]

 

[73diver]

Thanks everyone. I appreciate all the feedback. I do have a sidemount rig which is my preferred diving rig, solo, tech and otherwise around home. For air travel, I usually use my little 6# Seaquest-Malibu backmount BCD. I may elect to travel with the sidemount.

 

[uncfnp]

Those that have done it, I am curious what the reception to SM has been on Caribbean dive boats and if those accustomed to steel tanks have added weight to the Al 80's to compensate for the differences in buoyancy.

 

[tbone1004]

not familiar with the caribbean dive boats, but it has been reported as a non-issue by buddies of mine, both single and twin tank. No weight added to the tanks, put it on your back and they trim out just fine. You can add weight to them, but it's better to put it on the harness itself if possible.

 

[uncfnp]

not familiar with the caribbean dive boats, but it has been reported as a non-issue by buddies of mine, both single and twin tank. No weight added to the tanks, put it on your back and they trim out just fine. You can add weight to them, but it's better to put it on the harness itself if possible.

Just curious. When I took SM from Edd he mentioned this might be necessary to get them to trim out correctly.

No way I would do recreational SM on tropical dive trips. Serious overkill for me that just isn't worth the hassle.

 

[Dhboner]

In my limited experience there is still a learning curve for caribbean dive operators when dealing with requests to sidemount. I think there is still the concern that the diver wants to extend the dive time by slinging two tanks and will either exceed NDL's or make everyone on the boat wait for them. As open water sidemount becomes more "mainstream" I think the operators will be more comfortable that you plan to do 2 dives not one. The other issue is that a boat crew will be more amenable to a sidemount diver if they can climb a ladder with the tanks still rigged rather than hauling them into the boat.

 

[uncfnp]

In my limited experience there is still a learning curve for caribbean dive operators when dealing with requests to sidemount. I think there is still the concern that the diver wants to extend the dive time by slinging two tanks and will either exceed NDL's or make everyone on the boat wait for them. As open water sidemount becomes more "mainstream" I think the operators will be more comfortable that you plan to do 2 dives not one. The other issue is that a boat crew will be more amenable to a sidemount diver if they can climb a ladder with the tanks still rigged rather than hauling them into the boat.

This pretty much mirrors what I have heard.

I saw my first boat SM diver earlier this month diving a UTD system off a Florida boat. Honestly it didn't look fun. What I love about recreational diving, the minimalist freedom that one can get with a BPW system, even with a pony and all the other paraphernalia I sometimes dive with, is negated in SM. At least in my SMS 75. I feel much more restricted in SM then single tank BM. And I just don't see any benefit in doubles SM recreational vs a simple BPW and pony. Not too mention that with the pony I can take it or not as my dives dictate.

And then add getting back on the boat fully rigged...

 

[tbone1004]

the trim weights were to get aluminums to handle like steels so the butts didn't float. Edd doesn't dive aluminums as his main bottles, so it is out of his area of expertise. With aluminum bottles you have to rig them like the razor/stealth guys do and clip to d-rings, either two fixed on each side, or sliding and it works much better. For single tank sidemount, it's literally just jump in and go, for twin tank, in a razor style harness it's still pretty easy, just put the neck clips on, jump in, and fix everything else on your descent. Granted, that's what I do cave diving with big steel bottles, but that's because everything is easier when horizontal

 

[James R]

AL80 work fine as a pony IMO.

Some friends and I have done "monkey mount" a few times - regular single tank BP/W with a tank on our backs and one or two AL80 slung. We did this in Bonaire, taking a 88min dive to the far side of the 2nd reef, where no other divers were - what a treat!

I am over-weighted with a SS plate, a 3mm full suit, and one AL80, so i just put 2lbs on each bottle slung. Blowing them down to 500 on our first test dive didn't result in any issues and I could easily hold my safety stop.