Great question and welcome to the Buzz!
After skimming the 32 page document from Grand Canyon NPS, please see page 19 (line 61) as it relates to leaving marks on natural objects
Understand your comment about limited visibility of chalk and its probable disappearance with rain fall
From my view point as a Leave No Trace Master Educator, chalk marks on boulders might encourage other not so responsible folks to add their own "signatures"

 

Didn’t Caldwell make a similar trip? You might see how he approached that topic.

 

As both a boater and a climber, here's my bias.
1. Sounds super fun.
2. If you're bouldering on sandstone boulders, leave the calk behind, as it's going to be super grippy as it is, and it's harder to wash chalk out of the pores in the rock without making a big impact.
3. If you're going to be bouldering on schist/conglomerate, use a brush to wipe what chalk you can off of the boulders.

My $0.02

 

Boater and climber here, and I leave the chalk at home. It isn't humid and generally isn't too hot in October.

My last trip down we brought gear to climb the tower up Monument Canyon near Granite, but we were way too worked after battling wind the first few days to even bother digging it out. I never seem to do much bouldering in the canyon aside from at Redwall Cavern - the side canyon hikes and scrambles are so good and unique, and you only have time for so much. Try to spend a bunch of time at Redwall though - pretty mind blowing, but definitely no chalk there.

 

Boater doing the canyon 13 times and former 11+ lead and lover of bouldering; please leave the chalk at home. I'd be pissed if and likely when I will see chalk scars in the canyon. Besides, your most challenging bouldering will be overhanging and hence never washed clean.

Also, your best bouldering will likely be on Redwall and Muav LS which will not need caulk. These limestones are macroscopically sharp and angular and microscopically course and abrasively.

Please do not forget that a broken ankle/injury is at least a several thousand dollar evac and your crew mates will deservedly be pissed to deal with you and the evac.

 

Please do not forget that a broken ankle/injury is at least a several thousand dollar evac and your crew mates will deservedly be pissed to deal with you and the evac.

^^^^This is what came to mind when I first saw the post. If you take a nasty fall, what would normally be a friend driving you to the ER would become a week or two getting bounced around every day rafting in a boat that was designated to avoid big hits and take the most conservative lines, and being dead weight for your group in camp. Or the buzzkill for the group (and you) of getting airlifted out.

Oh yeah, and since you asked, I'd be bummed if I saw chalk around a campsite. And it won't wash off after a good rain if it's under an overhang.

...and it's not a ditch, it's the Grand Canyon.

 

I'm not a climbing guy but have worked in stores that sold climbing gear in my younger years a while back. I've definitely seen some people climb a bit, but canyoneering seems to be more the name of the game. I know there is a really nice wall in the upper granite Gorge that I've heard of people laying over at. Not much of a camp...but it was worth it for the climbers. I wouldn't say it would be any fun for the non-climbers in the group though.

A lot of the rock at river level, especially once you get passed Phantom, is pretty loose and rough. Tapeats sandstone might be fun to climb and I imagine Blacktail Canyon being pretty exceptional. Definitely lots of scrambling opportunities everywhere.

I agree that I would be pretty conservative about using chalk... sounds like it might not be needed anyways. It doesn't rain very much down there even in the winter...so even if it only takes a rain or two...that could be weeks or months and a lot of the places you'd want to climb are under overhangs or in slot canyons that are sheltered from the rain.

From a guy who has to carry peoples stuff a lot... most of the bouldering crash pads I've seen take up a lot of space and don't pack down very well. If its on your boat and you are responsible for transporting it then do what you want, but if you are relying on the good graces of someone bringing their own boat and carrying your stuff... we'll just say that I would be annoyed to have to try and fit one of those on my boat. Perhaps consider borrowing a bunch of Paco pads and laying them out and/or only doing bouldering problems where someone can spot you and falling isn't a big deal. I'll repeat the notion that there is a ton of stuff to do, lots of hikes, lots of boating and side excursions to use up your time and energy. As with a lot of things like SUP boards, IK's and other toys...it sure is a drag to carry a large and/or heavy item down and only use it once or twice. I think if you are going to bring it... I'd really commit to using it.

Perhaps its me...but I might suggest doing a more standard trip your first time down and scout things out and see if you think a more climbing centric trip is something you want to do for a repeat trip (which most, but not all, people will want to do after their first grand trip). I promise it will still be amazing and you won't possibly be able to do it all the first time even without focusing some attention on climbing. I think a lot of the side excursions away from the river will cure your climbing itch as well since a lot of it involves scrambling and heights and mild exposure.

 

In the SW, experienced people use Colored Chalk if needed. Mostly, as stated, it is not needed, but if it is you have it at least and no one will ever see it. Red would be what I would bring. IE... Colo - Rado

 

Been on trips when climbing gear was in a dry bag for most of the trip. They got the gear out once. (Yes. not boudering) Seen lots of problems in Redwall, but mostly people are in that incredible space not off in a cramped corner.

It is nice to have climbers on the trip that might want to lead a smear up a side canyon to set a rope for the other non-climbers.

Most accidents happen in camp.

Enjoy the Grand experience.

 

Lots of good input. For my POV as a climber and a boater, I'd say I would be mildly offended by chalk in the Canyon. Not on the same level as trash or graffitti but the ethic is LEAVE NO TRACE. That is your answer right there. I also second the concerns about injury. We have brought ropes and done some low level top-roping and used them in canyoneering but always with an eye towards not pushing the boundary. Climbing in the canyon is not stellar to begin with, and so many other things to do that there is really no need to chalk up

 

One more vote for no chalk. Every impact we make degrades the experience at least a tiny bit for someone else. And do you really need chalk to climb? On grippy rock? Would it be an in interesting experience to climb without chalk for a few weeks?

 

Update 6/25 - Thank you all for the input! Just what I was looking for. In response to your thoughts, I’lI forego the crashpad and chalk, bring an old pair of climbing shoes and keep it lowkey. As stated, I definitely do not want to get injured down there. I can also totally understand that chalk marks on some boulders would be an eyesore to many. So I think I’ve got my plan in place! Thanks again - I’m looking forward to this trip!!