That is a valid choice of course. An LP95 is horribly negative when full - very similar to a HP130.LCF wrote:I don't use a different wing with a 130 than I do with my 95, and I wouldn't go to a smaller one if I used smaller tanks.
If you're carrying five pounds of gas around that you're not going to use, you're compensating for that mass and it is costing you gas. At 4 or 5 atmospheres, that volume is going to add up. Further, whether that compensatory gas is in a wing or in a drysuit, it is increasing your drag and you are working harder. Carrying pounds of gas around that go well beyond a normal safety margin is worse than carrying those extra pounds as lead on your belt. For people whose air consumption is higher than they'd like, the best answer is to look at their equipment, their dive practices and their level of comfort - find ways to improve efficiency. Compensating with huge cylinders hurts their efficiency and may well steepen the curve if they're hoping to improve their air consumption with more experience. Wing size must also be adequate to float the equipment independently of the diver at the surface.The lift on my wing is primarily set by my exposure protection. After all, even with a 130, you're only compensating for about 9 pounds of gas.
Improving strength and balance is not going to eliminate the risk - it helps - as does minimizing the complexity and mass of the equipment being carried.I do hear the bit about the increased risk of getting to and from the water. I often dive doubles on simple dives here, just to stay in practice with my drills for the cave diving I do, but I don't take them to sites like Day Island Wall, where the access raises the risk of falling. I have already broken one bone diving and have no desire to break any more. But I think the answer is strength and balance training, not less gas . . .
It sounds like you had the right amount of gas to handle the contingency. Should be glad you didn't have to deal with that problem with a Heiser 190. You should know that a simple problem like that can arise at any time, and allow for that. If <500psi at your safety stop was eating into your comfort zone, you needed to turn the dive earlier. The same problem could easily have occurred with a larger cylinder, and you might just as easily have ended with an uncomfortable reserve at your safety stop if you managed your dive the same way.I view the extra gas I haul around as insurance, in case I get delayed. I have had one dive (with Bob) where we had to deal with a tank that came loose at about 95 feet. It took some time to convey the problem and some time to fix it. I was diving a 95, and ended that dive (which never went into deco) doing a safety stop with less than 500 psi. Nobody ever ended a dive wishing they'd brought less gas.
Nobody's arguing against having some insurance - but how much? One can have so much insurance that it increases your odds of making a claim. I frequently end dives and think to myself - that would've been more fun with less stuff hanging off me. This is why I have a selection of gear - single LP72s on up to HP100s and a set of doubled LP72s. I try to select the right gas capacity for the dive and the rest of my gear is configured to match. One of my favorite configurations involves my wetsuit and my freediving belt, along with an AL19, a first stage and one second stage. No buoyancy compensation necessary - don't even need an SPG. Occasionally I'll dive with someone new and they'll tell me they like to dive with a 119 or a 130 because their air consumption is pretty high - then I'll see them huffing and puffing their way to the water, starting the dive out at a loss. I'll look over at them during the dive while we're holding position in current and they'll be hanging there at a 45 degree angle with a big bubble in their wing, pumping gas through their reg at an astounding rate - eyes wide and kicking madly with up to 4lbs of lead strapped around each ankle. And I think to myself, "yes, I can see that your air consumption would be high" - good thing they carry lots of insurance.
To me, the oversized cylinders being used by many newer divers improve their odds of getting enough nitrogen loading to be a real problem when they either panic and bolt to the surface or they lose control of their buoyancy and cork because the big pocket of air they were carrying around in their suit/wing to compensate for the weight of the gas rapidly became uncorrectable. It's best to keep things simple, and learn to manage your dive so that you have enough gas left over when you reach the surface - it's done the same way with a 72cuft cylinder as it is with a 130cuft cylinder.