I can't imagine diving Manatee on OC with a Tekna lol
Other divers have told me its a pita on CCR because of the sawtoothing but I didn't feel that way. Maybe its a function of differences in how we run our dil and Adv and how close we are to min loop volume + willingness to vent and add.
Keep in mind, some of us use the distance from Friedman when we talk about distances in Manatee (I'm one of them), others use distance from Catfish, which adds 2000' to the number.
When I was a young dumbshit, one of my regular dives was to hop on my Mako (Tekna DV100) and ride back 5000' (from Friedmans). Invariably it would die on the exit and I usually had to kick out the last 1500' to 2000'.
In 1998, my friend Derek Hagler and I did a 9k (from Friedmans) there. We both used a Gavin (33ah) and a Mako for our DPV's on the dive and we did it on a quad stage, reserving tons of backgas. We each had two stages in the cave before the dive, swapping out at each of the two stage drops.
Really, the biggest challenge on the dive was primary lights. Remember, this was the day of lead acid battery packs and 50w halogen bulbs. A GREAT battery pack was only good for 180 minutes, and the bulbs were so fragile that if you flipped on a fully charged pack you had a risk of blowing a bulb. We cracked this particular nut by staging lights, using a lantern grip Underwater Kinetics 800R (I think it was 30w halogen), during the middle portion of the dive. So we went in on our primary lights then about 40 minutes into the dive, when we dropped the second stage, we switched to the 800R's -- using about 20% of our primary light at the start of the dive helped minimize the risk of blowing the bulb when we fired it back on. On the way out, we switched to the 800R's for the middle portion again, so we wouldn't be fumbling with the lantern grip while trying to manage four stage bottles.
Entry and exit was from Friedman. If you've been in there, you know that's not a fun place to pop through with 2 stage bottles and 2 scooters, let alone come out with 4 stage bottles and 2 scooters. Thankfully we had some great help that met us and took all of our empties and dead scooters..
In terms of modern times, well this weekend one of my buddies and I had originally planned to do a 12k run (from Friedmans) tomorrow, but putting in at Catfish so it would be a 14k, but it looks like we're doing something else in another part of the cave instead. Our gear plan to do that dive involved two modern scooters (an XK1 and Valkyrie for each diver), a modern light (LED Light Monkey w/20AH pack, good for about 12 hours), a CCR and about 400 cubic feet of bailout each.
CCR sawtoothing at manatee can be real, especially past Friedmans. The first 1500 to the pillar room has a ton of depth variability from 100' to 30', over and over and over again. If I'm on an eccr I drop the setpoint to 0.5 for that stretch and manually keep it in the 1.2 range at the deep portions, that helps minimize the solenoid going batshit crazy.
So how challenging is cave buoyancy with a CCR? As someone who has never used a CCR it seems that you would have to learn buoyancy all over again and the precision buoyancy that cave diving requires may take quite a long time to acquire.
Buoyancy is different, but it's not really "that bad". The big challenge was the ability to ascend/descend, it's just different -- on OC you can initiate an ascent by simply inhaling deeper, or descent by exhaling. On CCR you need to either adjust via wing, counterlung volume, or tilt your body. I described it as feeling like I was trying to run on ice but that I wasn't moving, however once you get the hang of it it can quickly become second nature.
Sounds horribly uncomfortable and perhaps rather inappropriate at best.
