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The Secret of Speed

I’m going to let you in on a secret. It’s super-secret. Hidden in plain sight, of course, as all the best secrets are. But it is so generally undisclosed and inscrutable that a room full of Illuminati Freemason CIA double-agents seem to have a hard time cracking the code. Here goes… When you bring a DPV into a cave: you don’t have to go full-speed the whole time. An even deeper secret is that you don’t even need to keep the DPV with you the whole time. There you have it. Protect it with your life. Over the last week I have been working someone towards their Cave DPV certification (which they wound up successfully earning!). Each day so much of the debrief has been about JUST how task-loading this new piece of equipment is. Another frequently discussed point has been JUST how much attention it takes to do all the other stuff we get so used to as divers; ie buoyancy/trim/stability, referencing the line, referencing the cave, maintaining clear team communication and cohesion, back-referencing and way-pointing the dive, etc. Your average diver goes somewhere between 40-50 feet per minute. Your average Floridian, taken off the leash of flow, will go 70fpm. Someone as *ehm* energy-conserving as me tends to hover around 30fpm. At any of those speeds it is perfectly easy to frequently reference the line/cave/team in between sometimes leisurely stretches of simply staring at something beautiful as you lazily move past the whirls of seemingly molten rocks around you. A glance 30 feet ahead will inform what the line and the cave are about to do a minute or so from now — and with that you can get back to being in the zone. The first question, I suppose, everyone asks about DPVs is always, “How fast does it go?” Too fast, honestly. At top speed there is nothing comfortable about DPVing for long periods of time. However, the average cruise speed most divers tend to fall into on a scooter is in the range of 150fpm. About three times as fast as swim speed. At that speed a glance 30 feet or so ahead will only inform you where the line just was a few seconds ago. There isn’t much appreciation of single formations; at that speed you’re appreciating the twists and curves that the water took to create the cave passage itself. Without constant focus, team separation can happen in a heartbeat. And being “in the zone” can very quickly lead to being on the wrong line, having blind jumped, or following someone on a blind jump, during just the briefest glance at your pressure gauge. Because of this I have heard it much repeated and repeat it myself: You’re going three times as fast — which means things can go wrong three times as fast.


Getting back to the worst kept secret in DPVing… You don’t HAVE to go top speed. You don’t even have to go 150fpm. All modern scooters I know of have a speed control, most of them are easy to use even while underway. If, for example, the controller has 10 settings, there is no DPV scuba law that says you can’t keep it on 3 or 4. At the very least, until it’s a cave you know well. Perhaps a cave that you’ve swam a zillion times in the past. One where you have favourite passages and which you know three different ways to get there which each have favourite formations along the way. Most of all, caves where you know exactly where the line is the entire way and could probably describe 80% of the tie-offs if you set your mind to it right now. Caves where you know exactly which turns pose the greatest risk of confusion or team separation. In that case, by all means… open that throttle up and pretend you’re doing the Kessel Run. I can’t even tell you how relieved I was when, on our first long-haul trip on the scoots, student was leading at about 40% or so speed. An experienced diver and cave diver, they took to piloting the scooter through the cave easily enough. But as I watched their light whip pointedly to the line they’re unfamiliar with every few seconds, as we moved at a modest speed, as they would instantly stop and cover their light if I so much as dimmed my own, I knew I wasn’t going to have some sort of “Come to Jesus” talk about the dangers of being all Top Gun about it right out of the gate. There was an intuitive knowledge that you are allowed to scooter slowly. Even took to scootering at about swim speed through tight and twisty stuff. Turning the speed controller down to where the prop is barely spinning, you are barely even moving at swim speed. But as the walls and/or ceiling close in, it’s perfectly easy to stick your fins out straight and motionless to avoid cave contact, and slowly let the scooter pull you through something little. Again… as opposed to, “I’m pretty sure I can make it!” with an attempt to get through a major restriction without even considering coming off the trigger for a moment. And, finally, there are those moments when you look at the passage in front of you. You have planned the dive against a map which indicated at this point the passage is going to get damned small. There may or may not be something big on the other side, but by virtue of not knowing one way or the other, having never dived this spot before, do you really need to risk having to push the scooter through some corkscrew you don’t know? So why not find out while swimming less encumbered. When I first bought one I thought of it as a taxi. The point of it was to get me somewhat quickly past all the passage I knew like the back of my hand to the places that, heretofore, had been out of reach. At which point I’d always planned to “park” the DPV on the line and set off swimming. And, in so doing, start getting familiar with those, more distant, passages. Eventually, after dive after sometimes long dive, one gets comfortable enough with this or that system, with the broader perspective about how water carved these caves and, so, be better equipped to read the twists and turns before you. With experience come the more focused attention required, more comfortable piloting the gizmo itself with hands starting to form muscle-memory about turning things on and off or clipping things on and off. It all becomes, just as much as any other piece of gear, familiar to the point of comfort. And sure, then, one can start to get a little more aggressive about how to steer through passage. (Though, it should be mentioned, this is yet another dangerous moment in one’s career. Because this is exactly when complacency is the greater risk.) I’m going to let you in on one other related secret. It has to do with the sometimes most, sometimes second-most frequently asked question about DPVs. “How much did that cost?” A lot. They cost a lot. But that’s not the real kick in the teeth. The secret kick in the teeth is that if you’re going to buy one… you still need a second one as a tow-scooter. For arguments’ sake lets say you’ve got 30 minutes of bottom time. Swimming at 50fpm that puts you 1500 feet into the cave. Scootering at 150fpm that puts you almost a mile back. What happens when, a mile back in the cave, your scooter dies? With 2/3rds of your gas remaining to get you out that puts you about right where you could have swam in when your tanks run dry trying to swim out. So the question is not, “How much did that cost?” the question is “How much for two of them?” And, follow-up question… how completely comfortable with all of your existing gear are you that you can easily amalgamate in clipping two largish machines made of handles and clips and cords and angles (which want nothing more in the world than to get completely tangled in cave line) to yourself? I can’t count the number of times, over the years, I’ve heard people or of people who got their Full Cave cert last month, but have the lettuce to buy a scooter this month… and do. Or the people who just borrow a friend’s scooter and head into the cave with it after their buddy gave them a 10 minute demo in open water. Those are the sorts of things that give me a searing pain right behind my left eye. We all heard it in our Cavern class: the number one rule of accident analysis is lack of training. But, somehow, it seems that in this one case, contrary to all educational theory: first learned is worst remembered. But now you know a couple of good secrets: You don’t need a scooter right away, take your time and work up to it. You need to be trained and experienced to plan and use one properly. You don’t always need to be going balls to the wall. You can park it and familiarise yourself with new cave while swimming. Feel free to share them around. So that they aren’t secrets anymore.


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there is the other side of this coin as well: dragging experienced Cave DPV divers along for a swim only dive. We had a recent transplant in cave country join us on a dive that we have done many times (Ginnie: Hill 400 to Bats, 104+single stage), and always thoroughly enjoy. Admittedly, we are not your typical Floridan cave divers, taking things slow and stopping to check things out was always part of our training. 20 minutes bottom time from a 5 minute primary install in the Eye to the esses before Hill 400 for the stage drop puts it right around 30 fpm ish?


Their reaction to the debrief post dive? 'That was one of the most chill dives…


いいね!
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