100 or 120cf tanks in Coz?

[PaulVS]

I like to blame it on the fact I have abnormally large lungs (x-ray techs have to do 2 separate chest x-rays, a top and a bottom) but the fact is I'm an air hog. Especially irritating is that I'm the natural "fish" and had to convince my wife to learn to scuba dive... yet she has half a tank left when I'm ready to ascend with an 80cf tank, so obviously her dive is cut short as well.

I always ask for 100's when setting up with the dive ops in the caribbean, but most of them act like I'm asking for my own private submarine, although I've found that if I press the issue I usually get set up. I haven't even tried asking for a 120, nor ever tried diving with one at all.

Trip to Cozumel in June and likely Bayahibe in the Dominican in September. Any tips on getting larger tanks or op's there that I could even get 120's with? Anything wrong with going with a 120? (I understand I'd use less lead)

 

[wnissen]

Aldora has 120s available, with the correct nitrox to boot, and they pick up right at your hotel's dock on small fast boats. Highly recommended.

 

[Moerae]

I don't have the answer for your primary question, but I'm wondering how often you dive and how comfortable and sorted out you are in the water?

Have you double checked that you're properly weighted? (zero air in BC, at 15 ft, with 500psi in your tank, without kicking, and comfortably neutral)

How's your trim? I don't mean like you have to look like a cave diver or anything, but if you have trouble being horizontal when kicking that can take a lot more effort to swim around. Are you flutter kicking all the time? Do you kick downwards to hold your position in the water or are you able to relax and hover (Not a "perfect" hover or anything, but mostly motionless and relaxed)? Do you use your hands a lot to move around?

If you can, an experienced mentor or instructor that can help you dial in your weighting, buoyancy, trim, and kicking can make a huge difference in air consumption. As I got more experience diving and got that stuff dialed in I cut my consumption rate by like 30-40%. It makes a huge difference.

Anyways, not trying to derail your question with my advice, just throwing it out there in case you hadn't considered any of this. A lot of people scoff at "snobby" divers or spending time and effort on dialing this stuff in, but it genuinely makes diving take so much less effort. Way lower consumption rate, less tired after a day of diving, etc etc.

 

[PaulVS]

Anyways, not trying to derail your question with my advice, just throwing it out there in case you hadn't considered any of this.

No worries, I do appreciate the input. I've been diving since the 70's (although uncertified and rarely back then) much more the last 20 years.... and have tried a lot of solutions, gotten my equipment down to minimum, (travel BC, integrated 2nd air, no unnecessary gear) and worked carefully on trim. I did find a set of full-foot fins that has cut down my kick effort compared to my open-foot. But It really hasn't made a lot of difference. I am extremely comfortable in the water and have been as long as I can remember (High school swim team even) and my breathing seems to be very relaxed when diving.

Probably the elephant in the room I haven't mentioned is that I smoked for many years. I don't anymore, but it might have had a negative impact.

 

[PaulVS]

Aldora has 120s available, with the correct nitrox to boot, and they pick up right at your hotel's dock on small fast boats. Highly recommended.

Thanks! Just sent off an email to Aldora.

 

[Rob9876]

Tres Pelicanos has 100cf tanks available.

 

[NovaCane]

I'm in the same boat, no pun intended. Gas hog, never have dived with 120s, diving with Aldora in July. What is the recommendation for weighting when using steel 120s vs 100s?

 

[divingjd]

Aldora has HP steel 100s and 120s. I aspire to be able to use a 100. I’m getting close, but there’s always that one dive I make it back with just barely 700 and lose the confidence. Lately, they’ve been getting some 117s. Really nice tanks. A lot shorter than the 120s with a neglible difference in volume. Bigger in diameter, but once your tank strap is adjusted, who cares? It’s my new favorite tank.

 

[cozcharlie]

@ChuckP can give a more definitive answer , but I believe most shops can come up with 100s fairly easily. Seems like a friend used to use them often without much of a hassle , but that was probably a decade ago (although they might get scarcer during super-peaks like Christmas and Carnival)

120s are likely a taller order. Some shops like Aldora dive 120s to get extra long dives for the entire group, but diving a 120 doesn’t really help you if most of the other divers are on 120s also.

 

[OTF]

Assuming you really do have your trim and buoyancy dialed in maybe cardio/endurance exercise would help. Do you find yourself winded on dives? Also taking some time on the surface to relax before descending saves a surprising amount of air, as does staying a bit shallower if it's an option.

This may be more training, cost, and gear than you want for more air than you need... but you could sling a second 80 (like a big pony bottle that is part of the gas plan), or take a sidemount course and dive that way, or even rig up independent doubles. Those options would all work with rental Al80s from anywhere. Adding a second tank really isn't as cumbersome as you might imagine. You get a huge amount of air, and added redundancy. Manifold doubles are ideal but likely even harder to find than 120s.