Thoughts on how people do the Grand Traverse

[rddvet]

While reading through the thread on recalculating thirds, the topic of recalculating thirds on the Grand Traverse at Peacock came up, specifically on the fact that there are multiple exits. I've been meaning to have a discussion on this topic, but have been hesitant to as I think it's slightly controversial and I don't want to get flamed. For clarity, I have not yet done the traverse, because there's been lots of other dives in Peacock I'd prefer to do.

So during my training, I had different instructors for Cavern/Cave1 and Cave 2. Both instructors used the Grand Traverse as examples for teaching advanced navigation and to push the idea of learning the cave before making advanced dives. Both instructors had the same opinion on the Grand Traverse, and their way of explaining it is obviously taking the most cautious approach to a long traverse.

To take anything superfluous out of the equation, let's just say we want to do the traverse from Orange Grove to P1. That means along the way our POTENTIAL options for emergency exit would be Challenge, Olsen, and Pothole(which I know is no longer an option), other than turning back to Orange Grove or pushing forward to P1. I was taught by both instructors the appropriate way to perform the traverse would be the same as learning a new circuit. You would start by doing several dives as learning the cave dives. Starting from OG and diving to 1/3s (or whatever gas plan you choose), you would mark the line or notate your turn point in your wet notes. You would then do a dive from P1 towards OG and noting if you made it to your previously notated turn point. Both instructors recommended doing these dives several times to prove consistency. Once you have proven that you can get to the "mid-point" repeatedly and easily using your gas management plan, then you can attempt the traverse. While doing the traverse if you don't hit your mid-point, you turn and head back to your entrance.

In discussions in both classes, it was agreed that while Challenge and Olsen could be used to climb out in an emergency, why take that risk. I'm sure I could climb out of Olsen, but Challenge doesn't look fun unless you're leaving all of your gear behind. Obviously doing the traverse in this manner is the most cautious approach.

Now the kicker. Since being given my ticket to learn, the more people I hear discussing the traverse, the more I hear it being done completely differently. The way I very commonly hear people discussing is that they would dive from OG to Challenge. Once at Challenge they would recalculate thirds. With this new recalculation, if they didn't hit Olsen by the time they hit thirds they would turn around, using Challenge as a potential emergency exit. If they did make it to Olsen, they would then recalculate thirds again for the rest of the trip. Where some differed is that with some the new recalculation would be planned to get them to Pothole, and others it would be to P1. If they didn't hit their new mark before thirds, they would have to make a turn decision.

Compared to how I was taught, this alternative choice seems frought with risks. I do realize many people can do the traverse without a stage or know from experience that they can hit the midway mark and therefore just finish the traverse. The majority of people that told me they did the traverse based on this second method of travel were using this gas planning of recalculating thirds on their first attempt at the traverse. When I've explained that's very different than the conservative way I was taught the responses have usually been either "that's how people who have done the traverse taught me" or "well that's how everybody does it, so it's fine."

I tend to be ultraconservative, so to me the recalculating thirds is not my cup of tea and something I wouldn't do. There also seems to be a little bit of pride in discussion I've had with people that carrying a stage to do the traverse is not necessary even if it's just meant as a safety.

So what seems to be the norm? Is what I was taught in my courses what most people are really doing, and my discussion with people that do the recalculation isn't typical? Is part of your plan for emergency to climb out of challenge or olsen really a smart one? I've often wondered if the people who do include a climb out as part of their emergency planning taking into account that it's possible the emergency is an incapacitated diver? How would they get you or your buddy out of Challenge if he/she had a heart attack and can't climb out under their own power.

My intention is not to say that people who recalculate are wrong. And I know my conservative mindset isn't the norm. These are just questions I haven't really been able to understand and I've pondered since the first time I was told of the recalculation method of doing the traverse. Hopefully my long stream of consciousness post isn't too rambling.

[fishinmaniac]

I did the grand traverse from orange to challenge to Olsen to p1 this past weekend. I was diving with a someone who has 20 plus years of safe cave diving who I dive with regularly, know well and trust. We carried a stage that we did not plan on breathing but if it was needed it was there, otherwise we decided to recalculate thirds on the surface of each sink to make sure things were correct.

I have dive orange grove to challenge 5 times prior and p1 to Olsen 3 times before. The section upstream of Olsen to challenge was blind travel however I knew how much gas it takes me to do the dive from p1 to Olsen.

I carried the stage because I wanted to ensure if I had to turn during the blind travel area that I would have plenty of gas to make it back to orange grove, your swimming against the flow in that scenario and will consume more gas.

The dive went great, and long story short I ended at p1 with well above my last third of gas remaining and an untouched stage bottle.

Would I do the dive again simply recalculating and without the stage? Possibly but your assuming everything goes perfectly during the dive.

Would I recommend someone who has never done this dive before do it by recalculating thirds?

No, I don't advocate anything, that is 100% personal preference and that's why I chose to carry the stage.

[Jon Nellis]

When I did the traverse, I had already done a circuit from P1 to Olsen to the Peanut restriction and back via the peanut line. I knew if I could reach the peanut restriction from Orange Grove on a third, pressing on past that point would be no problem. I ended up hitting the peanut restriction with just over a third and had just enough gas to deco and still exit with 1200. We did not plan to use the sinks, but considered them as our safety margin instead of carrying a stage.

Had I carried a stage it would have slowed me down enough that I would have had to factor the extra air into the plan. YMMV

[sandy]

The one time I have dove the traverse, we used a stage and:
1. Dove Peanut to Challenge on less than 1/3s where we gapped to OG which we had establised as our turning point,
2. Surfaced at Challenge for a few minutes to talk and drink a water and then returned to P1
3. Dove from OG to our gap reel on less than 1/3s so we continued to Peanut picking up our gap and jump spools. We did not stop at Challenge because it was close to closing time.
4. Posted on CDF for someone to pick up our primary from OG
We were within 1/3s but I needed the stage. Next time we will do the same thing. I will pass on recalcuating thirds for the traverse. It seems like we had several dives to within 200 to 400 feet of Challenge each way by the time we did the traverse.

[rddvet]

The one time I have dove the traverse, we used a stage and:
1. Dove Peanut to Challenge on less than 1/3s where we gapped to OG which we had establised as our turning point,
2. Surfaced at Challenge for a few minutes to talk and drink a water and then returned to P1
3. Dove from OG to our gap reel on less than 1/3s so we continued to Peanut picking up our gap and jump spools. We did not stop at Challenge because it was close to closing time.
4. Posted on CDF for someone to pick up our primary from OG
We were within 1/3s but I needed the stage. Next time we will do the same thing. I will pass on recalcuating thirds for the traverse. It seems like we had several dives to within 200 to 400 feet of Challenge each way by the time we did the traverse.

That coincides with how I was taught, although pre-placing the gap or doing it on the traverse is personal choice. On a second note, I am also shocked at how many people choose not to gap the jumps and perform a visual jump.

[sandy]

That coincides with how I was taught, although pre-placing the gap or doing it on the traverse is personal choice. On a second note, I am also shocked at how many people choose not to gap the jumps and perform a visual jump.

In the FWIW category, seems like the gap is 8 to 10 feet. Bad memory says both ends of the GL at Challenge are really close to OW. Someone else may correct me though.

[rddvet]

In the FWIW category, seems like the gap is 8 to 10 feet. Bad memory says both ends of the GL at Challenge are really close to OW. Someone else may correct me though.

Sounds right. Funny you brought that up. One reasoning for why the diver didnt see a need to gap the jump was because it was really ow anyway. I can see that as a semi-valid reason, althought my trainers beat it into my head that that would be considered an unnecesary risk.


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[huxley]

I think diving it safe and doing it within my interpretation of 3rd's, meaning twice the amount of gas for the way back that to get to that point, requires to dive it from both sides and mark the max penetration including notes about mine and my buddies gas consumption as well as notes about flow.
If i reach that mark from the orange grove side on 3rds, which should be around half way between challenge and peanut restriction and i have at least twice as much gas that i used from p1 I decide to either go or turn. This requires equal gas consumption and tanks for a team. As well as no flow or flow working in your favor.
I like to exit peanut tunnel rather than main line.
I don't like to take emergency exits into my gas planning and rather keep them for additional safety.

[sandy]

...my trainers beat it into my head that that would be considered an unnecesary risk.

Same here. Also, it just gives me extra practice with spools.

[RN]

The way I've done it is to start at P I. Swim to Olsen, gap the lines, continue the swim until hitting turn pressure. Mark the line with a cookie. Swim back to P I.

Begin dive at OG, swim to Challenge, gap the lines, continue the swim until hitting turn pressure or reaching your cookie. Once everyone verifies the cookies, continue the swim toward Olsen. Pull the gap reel at Olsen and continue out to P I. We don't surface at Challenge or Olsen and we don't recalculate turn pressure.

A third dive is done from OG to Challenge to pull the gap reel and pull the primary reel at OG. However, if I'm with someone with a decent RMV then the third dive is just to pull the primary reel from OG because we made it to Challenge on the first dive.

A key thing to remember is to either use the same size cylinders or to use the smaller cylinders on the first dive when marking your turn point. This way you know you have the same amount of gas or more to exit from the point when coming from OG.