# floppy or stiff - low water edition



## JohnR (May 23, 2005)

Running through a couple of older threads looking for shuttle info, I notice an issue that I have heard conflicting views on: raft air pressure at very low flows.

Prevailing view here seems to be to drop pressure in an effort to slither over rocks. Howsomever, I consulted with raft goddess Holly of Vanguard, and with someone who answered the phone at NRS and they opin-ed that they would do the opposite - at low flows they would crank it up a bit, and only come down at > 50,000 CFS (and yes, that is the correct number, I asked) which I think happens somewhat rarely on the upper Colo, R Fork, R Chama, etc., where I hang out. 

I personally have followed the slither model, but am now revisiting that.

So, stiff or floppy, and why?


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## g.soutiere (Jul 7, 2009)

I use the same pressure either way. From experience I have found you want a stiff raft at high flows, a soft raft takes more work and gets surfed easily. I can see the advantage of a soft raft at lower flowers as you can shift where the high pressure area is and slide across rocks easier.


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## Gremlin (Jun 24, 2010)

The Roaring Fork was running at 900+ cfs. after recent rains and snowfall; up from 600 cfs. Last year, I didn't get to run it in the Fall and 1000 is my usual cut-off for a 16' cataraft. I opted for squishy tubes knowing that the rocks I might hit were smooth and slimy. If the tubes were pumped more, I would have hung up.

If anyone tells you the Fork, Chama, and upper Colorado regularly reach 50,000 cfs., discount their opinions immediately.


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## g.soutiere (Jul 7, 2009)

Good point if the fork and upper c hit 50000 CFS everything down river would be flooded worse than the front range


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## JohnR (May 23, 2005)

*50k*

Yeah, but at 50k you would definitely draw the buttboater crowd from the front range. Wonder how long it would take to get from State Bridge to Cisco at that level...


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## cataraftgirl (Jun 5, 2009)

Many trips down the Middle Fork Salmon in the fall at low water have made me a "firm" believer in the soft tubes. I've tried it both ways, and soft tubes = much less hang- ups.


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## JohnR (May 23, 2005)

*hmmm...*

USGS says the max on the Colo Glenwood gauge is 3,110 from 1999, max on the Fork Glenwood gauge is 1,250 from 1986. I know guys dumb enough to run Shoshone at 50k. Probably be ranting here if the cops kept them off. 

Given all that, why would you run with less pressure above 50k. Last I heard Ms. Holly was selling rafts in Alaska, maybe she's back.


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## JohnR (May 23, 2005)

Peak of record is 31.5k in 1984 for the Colo, the 3,110 is for Sept 30, so that channel probably could handle 50k. Might lose the railroad... now I'm wondering what the 100 year flood plain looks like... what did that canyon look like before Dillon, Green Mountain, Shadow Mountain, if it hit 31k WITH them.


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## JohnR (May 23, 2005)

Peak for the Fork before Ruedi is 19k in 1957. Interestingly, the Pan has not historically kicked all the much into the Fork, even before Ruedi...


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## JohnR (May 23, 2005)

I dunno, I think with 1 or 2 real wet years to fill the reservoirs followed by a heavy snow pack and then a hard 2-3 days of rain in early May you might get 50k on the upper c. Certainly you could see the 31k again.


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## Ka-Pow (Jul 14, 2013)

Low PSI for low water. If the boat is softer and encounters a rock it will bend over the rock easier, catching more current, and be more likely to free itself. Plus low PSI amplifies the diminished wave/hydraulic features at low water for a more exciting ride.


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## okieboater (Oct 19, 2004)

On low water rocky runs I have run soft tubes. As mentioned before, theory being the material can more easily bend around rocks where the firm tubes might puncture. 

For the big water runs, pump the tubes up for better performance in the gnar.


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## salmonjammer (Dec 14, 2011)

*I won't go with reduced pressure*

This photo is a 16' Hysides with 24'tubes almost completely submerged. Rower slipped an oar and dead centered the rock. Low pressure in the boat allowed it to swamp, pinning it to the rock. We had to completely unload and it folded in half and flipped getting it unpinned, but we were lucky to get it off at all.


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## cataraftgirl (Jun 5, 2009)

salmonjammer said:


> This photo is a 16' Hysides with 24'tubes almost completely submerged. Rower slipped an oar and dead centered the rock. Low pressure in the boat allowed it to swamp, pinning it to the rock. We had to completely unload and it folded in half and flipped getting it unpinned, but we were lucky to get it off at all.


I'm guessing this would have been the same outcome even with full pressure in the tubes. Soft tubes help "slime" over rocks, but won't prevent a dead centered pin.


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## JohnR (May 23, 2005)

That picture sort of reminds me of the old drunk driver wreck movies they use to make students watch before prom night. Maybe buzz should do a raft pin porn thread.


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## caverdan (Aug 27, 2004)

I've had good luck in low water by running my tubes at the same pressure as usual, but running the floor softer than normal.


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## carvedog (May 11, 2005)

salmonjammer said:


> This photo is a 16' Hysides with 24'tubes almost completely submerged. Rower slipped an oar and dead centered the rock. Low pressure in the boat allowed it to swamp, pinning it to the rock. We had to completely unload and it folded in half and flipped getting it unpinned, but we were lucky to get it off at all.


A good boatman always blames the equipment in the case of a pin. 

Recently did the MF Salmon with two passengers and gear off the top. 

Launched on 530 cfs. I topped off a bit at the top of the ramp to rig the boat and didn't add air until Indian Creek. 16.5 foot Maravia with the kitchen box, tables, cooler, 4 boxes and other gear. We made it through many areas cleanly for the most part. A couple of the others got stuck and released air out of tubes to get unstuck. 

But stay firm in your belief. Get it?

I am sure that your pin at Tipi Hole was uncomfortable to deal with but don't blame it on low pressure rafting. 

Refering to risk of puncture. I am in a Maravia so for the most part I am unconcerned with puncture. Low pressure allows the tube to deform around the rocks more easily instead of getting stopped or hung up on them.

I will say that if you plan on hitting a lot of rocks dead center in the middle of your tubes under your oar lock a stiffer boat might bounce off easier. Or could pin you harder. As in if it is stiffer when it does sink it will push everything further down into the water.


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## paulster (May 27, 2011)

I have experimented with dropping pressure mid-day, side by side with other rafts all day, after talking to MFS guides in low water, and am absolutely convinced that lower pressure in low water is better, partly because the raft slides over obstacles and partly because the tubes become more oval shaped and draw less water. This is very obvious if you ever follow a sweep boat in shallow water. My experience has been with a cat, but suspect you'd get the same with a round boat.


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## Avatard (Apr 29, 2011)

salmonjammer said:


> This photo is a 16' Hysides with 24'tubes almost completely submerged. Rower slipped an oar and dead centered the rock. Low pressure in the boat allowed it to swamp, pinning it to the rock. We had to completely unload and it folded in half and flipped getting it unpinned, but we were lucky to get it off at all.


Exactly how limp was that boat before it hit the rock? I've never seen a wrap that bad, usually all that happens is enough water goes over the edge to wrap the floor. That pic looks like enough water came over to completely submerge not just the floor but 70% of the boat. If this was a low water pin I honestly can't foresee that much push unless the tubes were mushy from the getgo.


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## Wadeinthewater (Mar 22, 2009)

paulster said:


> ...lower pressure in low water is better, partly because the raft slides over obstacles and partly because the tubes become more oval shaped and draw less water...


Very true. I have a cat with large tubes. The oval shape is quite noticeable when I am on the top end of a low water MFS trip.


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## waterismyfriend (Mar 30, 2012)

I've been guiding for 15 years and up until I began guiding on clear creek 3 years ago I just always went with the same pressure. After 2012 on the creek, and when we dropped below 150 cfs, I saw many older (and lazier) guides drop pressure so low that your butt dropped 6 or 8 inches into the tube. 

I tried their method and have to say it worked well down to 80 cfs. At that point I left the creek and went back to the Royal Gorge for high water (300 cfs!). I mean, we have to have standards right! Very low standards they may be...

Zach Sack


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## cataraftgirl (Jun 5, 2009)

My low water/soft tube experience has been in a cat. The tubes should not be mushy soft, just slightly less pressure than normal so that the tubes have a bit more give. I still get stuck more in the cat than the rafts do, but not nearly as much as when I ran firm tubes. Soft tubes helps, but getting stuck is still in large part the result of operator error.


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## Avatard (Apr 29, 2011)

cataraftgirl said:


> My low water/soft tube experience has been in a cat. The tubes should not be mushy soft, just slightly less pressure than normal so that the tubes have a bit more give. I still get stuck more in the cat than the rafts do, but not nearly as much as when I ran firm tubes. Soft tubes helps, but getting stuck is still in large part the result of operator error.


I totally disagree. You do a low water (1') selway trip on a cat and then explain to me how the first two days were all just operator error


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## caverdan (Aug 27, 2004)

Avatard said:


> I totally disagree. You do a low water (1') selway trip on a cat and then explain to me how the first two days were all just operator error


 Try doing the Selway at -1 foot. We passed our first planned camp on day three. 

On that trip I noticed the Avons did better with soft floors.....the NRS's stuck to everything....soft or hard floor didn't matter. The Aire boat slid off stuff better when it was rock hard.


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## cataraftgirl (Jun 5, 2009)

Avatard said:


> I totally disagree. You do a low water (1') selway trip on a cat and then explain to me how the first two days were all just operator error


I'm just saying that soft tubes aren't magic.....helpful, yes, but I take full responsibility for my lame ass moves. I will agree with you that sometimes it's not about tube firmness or operator skill, it's about a low, rocky river that's out to get you no matter what.


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