Dumb question about Mindbender anchor

[Scott P]

The latest thread reminded me of a question.

Dumb question perhaps, but how do you rig the last anchor in Mindbender when the pothole is full of water? I already know of the water bag methods, but don't think I'd try it on something like this.

Note: I've done Not Mindbender, which used to be thought of the real Mindbender, but I haven't done the real Mindbender, so don't know what the anchor situation is.

I was thinking of doing it a few times, but suspected that the anchor would be under water since it was during wetter periods (such as now).

[ratagonia]

The latest thread reminded me of a question.

Dumb question perhaps, but how do you rig the last anchor in Mindbender when the pothole is full of water? I already know of the water bag methods, but don't think I'd try it on something like this.

Note: I've done Not Mindbender, which used to be thought of the real Mindbender, but I haven't done the real Mindbender, so don't know what the anchor situation is.

I was thinking of doing it a few times, but suspected that the anchor would be under water since it was during wetter periods (such as now).

Rocks are considerably heavier than water. The volcanic rocks (Diorite and Andesite from the Henries) found from place to place have a density around 2.5 to 2.8. Regular Sandstone tends to be 2.0 - 2.6. https://en.wikipedia.org/wiki/List_o...d#Rock_density

Water having a density of 1, subtract that and...

Means, your under-water deadman needs to be about twice as big.

If you have looked at the pictures, you can see that the pothole at MindBender is VERY advantageous geometry.

One thing to note is that if a deadman is made for dry conditions, it is only half as good when submerged. Good thing most people build them at least twice as good as needed.

Tom

[rick t]

Interesting question, given the concurrent discussion in "Alcatraz Rescue. Many would say that what is really needed there, to safely protect that 155' free rap, is two good solid bolts, maybe up on the left wall not too far back from the edge. Oh yeah, somebody already put two good bolts in right there, and they wdere promptly yanked by some holier than thou sanctimonious clown from the better to have someone die than to "ruin the canyon for everyone" by drilling a hole in the rock, gang. My last prebolt time through MB there were three different anchor sytems set up, none of them inspiring, and using at least 70 feet of webbing of different colors. SO much cleaner, and more natural, than a bolt. If the pool at the lip is full of water, negating the deadman option there, perhaps you could get the proud MB bolt chopper to give you a quick lesson on water anchors, I understand he is an expert on them, and they are very reliable, and carried regularly by most canyoneers.

[Scott P]

Rocks are considerably heavier than water. The volcanic rocks (Diorite and Andesite from the Henries) found from place to place have a density around 2.5 to 2.8. Regular Sandstone tends to be 2.0 - 2.6.https://en.wikipedia.org/wiki/List_o...d#Rock_density

Water having a density of 1, subtract that and...

Means, your under-water deadman needs to be about twice as big.

I guess I should have looked at more photographs. For some reason, I was envisioning the pothole as much bigger as in holding your breath while inspecting and building the anchor.

Told you it was a dumb question.

PS, are you sure that the stuff in that area is Diorite and Andesite from the Henry Mountains? I thought of that too, but don't think that it is, but can't figure out exactly what it is (even though I am well versed with the geology in the area, as you probably are too). Coincidentally I was wondering what it just yesterday when I was in the Roost and even took a small piece of it home to see if anyone can identify it.

If we're talking about the same stuff, and I think we are, I've found some of that stuff, which appears to be river polished, embedded in rocks that should be older than the Henries.

[ratagonia]

PS, are you sure that the stuff in that area is Diorite and Andesite from the Henry Mountains? I thought of that too, but don't think that it is, but can't figure out exactly what it is (even though I am well versed with the geology in the area, as you probably are too). Coincidentally I was wondering what it just yesterday when I was in the Roost and even took a small piece of it home to see if anyone can identify it.

If we're talking about the same stuff, and I think we are, I've found some of that stuff, which appears to be river polished, embedded in rocks that should be older than the Henries.

I'm not sure it is Diorite or Andesite from the Henries.

But, it seems to be similar rock, and considerably denser and more solid than the sandstone. Erosion resistant. Could be limestone from the layer above (Carmel). Could be volcanics of some kind from the Orogeny that produced the Henries. Hard to tell without dating it, which takes quite a bit of equipment. The Geo map would give some clues, as would a REAL geologist.

If you have seen chunks embedded - you sure not in recent erosion-product conglomerates. The limestone layer above provides carbonates that create conglomerates in debris piles as water flows through.

Tom

[ratagonia]

Interesting question, given the concurrent discussion in "Alcatraz Rescue. Many would say that what is really needed there, to safely protect that 155' free rap, is two good solid bolts, maybe up on the left wall not too far back from the edge. Oh yeah, somebody already put two good bolts in right there, and they wdere promptly yanked by some holier than thou sanctimonious clown from the better to have someone die than to "ruin the canyon for everyone" by drilling a hole in the rock, gang. My last prebolt time through MB there were three different anchor sytems set up, none of them inspiring, and using at least 70 feet of webbing of different colors. SO much cleaner, and more natural, than a bolt. If the pool at the lip is full of water, negating the deadman option there, perhaps you could get the proud MB bolt chopper to give you a quick lesson on water anchors, I understand he is an expert on them, and they are very reliable, and carried regularly by most canyoneers.

Perhaps the Wasatch Mt Club Canyoneering class should include a section on how to tie a piece of webbing to a rock.

Apparently, instead, the Club teaches that every drop in every canyon has bolts in place, and one merely needs to put the rope through the ring.

Tom

[EvergreenDean]

Interesting question, given the concurrent discussion in "Alcatraz Rescue. Many would say that what is really needed there, to safely protect that 155' free rap, is two good solid bolts, maybe up on the left wall not too far back from the edge. Oh yeah, somebody already put two good bolts in right there, and they wdere promptly yanked by some holier than thou sanctimonious clown from the better to have someone die than to "ruin the canyon for everyone" by drilling a hole in the rock, gang. My last prebolt time through MB there were three different anchor sytems set up, none of them inspiring, and using at least 70 feet of webbing of different colors. SO much cleaner, and more natural, than a bolt. If the pool at the lip is full of water, negating the deadman option there, perhaps you could get the proud MB bolt chopper to give you a quick lesson on water anchors, I understand he is an expert on them, and they are very reliable, and carried regularly by most canyoneers.

Maybe we could get a fire escape installed in there to up the safety level even more! Screw those guys who think anchor building is a fun part of the challenge. Safety first! Lets make sure the least sophisticated canyoneer can always navigate every canyon. I like it.

[Scott P]

But, it seems to be similar rock, and considerably denser and more solid than the sandstone. Erosion resistant. Could be limestone from the layer above (Carmel).

Yes, exactly; same rock. It seems even denser than the rocks from the Henries.

I've found it embedded in the top of the Carmel Formation not far below the Entrada contact. This is the only place where I've seen it embedded, but in much of the other parts of the Roost you still find scattered rocks laying around and find them washed into in the canyons as well. Because it is so erosion resistant, it seems that these scattered super dense and hard rocks are still around long after the rest of the Carmel has eroded away.

[ilipichicuma]

I seem to remember that anchor being underwater when we did that canyon. It was solid as a rock. (No pun intended.) We actually wanted to pull it out and rebuild it, because the webbing there was such a mess since lots of webbing got washed downstream in a flashflood and apparently piled up there. That's what it looked like anyway. We couldn't pull it out though, and figured that was a pretty good sign.

[Mountaineer]

I seem to remember that anchor being underwater when we did that canyon.

Have you (or others) rebuilt a deadman underwater before? Assuming it is only a foot or two deep I hope (to minimize diving and brain freeze).

Do you pull up all the rocks you can find and tie them together as a pseudo-deadman or weight, or if you pull on it "hard" feel confident in what others have done before you?

I've left anchors alone that are frozen in ice, but any anchor that was under liquid water I've found alternative anchors...at least so far.

[ratagonia]

Have you (or others) rebuilt a deadman underwater before? Assuming it is only a foot or two deep I hope (to minimize diving and brain freeze).

Do you pull up all the rocks you can find and tie them together as a pseudo-deadman or weight, or if you pull on it "hard" feel confident in what others have done before you?

I've left anchors alone that are frozen in ice, but any anchor that was under liquid water I've found alternative anchors...at least so far.

Obviously, less comfortable to build a "deadman" in water or mud. But canyoneering does not promise you great comfort at all times...

Probably best to tie off several rocks and equalize. stacking rocks atop a rock under the water is not too reliable.

I have rapped off a piece of webbing disappearing down into the muck. I knew it was a pack that Bucky tied off and buried a year before. Pulled up as hard as I could! I think Hank and I will try to measure that tomorrow, and post a report.

Tom

[hank moon]

I have rapped off a piece of webbing disappearing down into the muck. I knew it was a pack that Bucky tied off and buried a year before. Pulled up as hard as I could!

X2...it was a long drop, too...scary thinking about it now.