riverreasearchcataraft

Catarafts for Science Projects.

Please see more cataraft science projects on our blog site

Photo Credits: Chip Rawlins , Copy by Chip Rawlings.

C. L. Rawlins <rawlins@carbonpower.net>

After using my Stretch Flyer Cat for channel mapping on the Snake in 2010, I was asked by Carl Legleiter, a University of Wyoming geomorphologist, to build a research boat for the 2011 field season. Having built several modular whitewater frames with SpeedRail fittings, I designed a new one to mount the equipment we planned to use for measuring the depth, current speed, current direction, reflectance, turbidity, and other characteristics.

The frame was basically a big lab-stand with various extra spars and mounting points for the high-tech gear and a foot-controlled trolling motor. Since the cat was intended for precision rowing on class I and II water, I ordered a pair of Jack's fishing tubes, 14 ft. by 19 inches, in gray fabric to cut down on reflectance. To that end, the grid floor and oarblades would be black. The frame came together nicely and when I inflated the tubes and rigged it for the first time, I knew we had a winner.

After trial runs on a local reservoir and on the upper North Platte, we were ready for ten days of fieldwork on the Snake. A field session is much like a Grand Canyon trip: if you don't have it there for the launch, you have to do without. The boat was ready, with the trolling motor mounted and hooked up. The Park Service doesn't allow outboard motors on the Snake, so we had to ask for a waiver to use an electric trolling motor, that makes no noise at all.

When the current speed edges up towards 2 meters/second, it's not humanly possible to hold the boat in place, let alone to row a straight line across the river. So the trolling motor provides a boost— I still have to row like the devil to steer the cat in a straight line. The pedal control allows me to row and use the motor at the same time, which takes some practice.

The science gear included an Acoustic Doppler Current Profiler (measures depth, current speed, and current direction), a turbidity sensor (water clarity), an echo sounder (depth and GPS location) and a spectrometer (color and reflectance of the water). These devices were linked by radio to a GPS earth station on a summit above the river. It took two hours to get all the electronic devil-boxes beepingm flashing, and communicating with each other, which they aren't always inclined to do. We launched just before lunchtime and rowed off toward the bend we intended to survey in detail.

The guides call it Swallow Bend, for all the bank swallow nests burrowed in the high cutbank. What interested us is that a rock ledge forces the current toward the inside, depositing a big pointbar on the outer edge. That's the opposite of what happens on most meander bends. It's also a beautiful spot, that I'm getting to know rather well.

New this year is a spectrometer, to measure the color and intensity of the light reflected from the water.

The spectro-thingie is in a backpack, hanging from the T-bar on the left. The fore-optic is mounted on the end of the spar, with a GPS receiver (the yellow & black box) to record the location of each measurement. Our groundlevel measurements will be correlated with airphotos and satellite images, to make it possible to map river channels and also to update nautical charts. On the yellow mast to the right is an echo sounder, that records the depth, with another GPS receiver on top of the mast.

For running cross-sections in swift water, I built a kayak mount for the Current Profiler, and Brandon Overstreet, a Ph.D student and kayak instructor, was able to paddle a series of beautifully straight lines where I couldn't do that in the cat, even with the motor.

Every rafter has watched kayakers paddling upstream to surf a wave: a 'yak is a lot more slippery than a full size cat with two people and a load of gear.

The science is interesting, but to be honest I do it to be on the water, rowing, looking around—

Photo Credit — Brandon Overstreet

I've been running cat tubes from Jacks' for 25 years in all sorts of places and they've never let me down— not even a puncture. If what I need isn't a stock item, they'll build it to my specs, for a fair price. To call me a satisfied customer is an understatement.

I'm a worshipper.

Note from Jack:

We absoutely love customers who take our products, mix them up with other technologies, and come up with something that is entirely out of our experience. Reading about this gives me great hope for the future of your environment. It would not be possible without the vision of our customers and friends. Thank you Chip Rawlings for being that kind of customer. We could never think this kind of stuff up on our own.

Stream Craft is now doing a lot more with these types of products. Please visit their face book site for more information.

Order inquiries: shop.jpwinc@gmail.com
Custom & Prototype inquiries: pschoser.jpwinc@gmail.com