Raft Porn Needed -Let's see them rigs!!! - Page 47 - Mountain Buzz
 



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Old 04-26-2013   #461
 
Boise, Idaho
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Have y'all measured to make sure your arms are the same length?

That might REALLY throw the calculations off if you find out your left arm is 4" shorter than your right arm...

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Old 04-26-2013   #462
 
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Missoula, Montana
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back to the porn

Here's an old foam floor Puma I acquired in Feb. for my little fleet. I put together a speedrail/toprail frame out of mostly used parts. Maiden voyage on the Deschutes in March.
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Old 04-26-2013   #463
 
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Sandy, Utah
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Originally Posted by Avatard View Post
If your towers are sticking out near the edge of the boat, and you broadside a rock (with oars shipped) it will be interesting to learn if you get any damage to the shaft, lock, or tower

With my situation, there is at least about 8" of tube to act as a bumper

Normally the nrs towers will spin a bit under duress. With a steeper pitch this might lose a little of that give

What sort of angle do you have on those towers? Too much and your oarlocks may tend to pinch the oars.
The angle isn't extreme. The oar locks are level. I don't have a front on picture, but if you look at this picture you might get an idea on the oar towers. As I look at pictures of my cat frame set-up, the raft oar towers look about the same, angle/outward lean wise. I've that system on the Middle Fork in the fall for many years with no issues on hitting the oar towers on rocks, or having problems with shipping oars. And the Middle Fork in the fall is chock full of rocks and tight places. So far, in 10 years of using an NRS frame, I've never had an oar tower budge on me at all. Hopefully I didn't just jinx it by saying that. As you know, a new raft & frame on it's first outing is always a work in progress to some extent. We shall see next week. How did your friend achieve a 2/3 1/3 oar balance on a 60 inch frame with 9 foot oars, without tilting his towers out a bit?
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Old 04-26-2013   #464
 
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portland, Oregon
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Originally Posted by cataraftgirl View Post

The angle isn't extreme. The oar locks are level. As I look at pictures of my cat frame set-up, the raft oar towers look about the same, angle/outward lean wise. I've that system on the Middle Fork in the fall for many years with no issues on hitting the oar towers on rocks, or having problems with shipping oars. And the Middle Fork in the fall is chock full of rocks and tight places. So far, in 10 years of using an NRS frame, I've never had an oar tower budge on me at all. Hopefully I didn't just jinx it by saying that. As you know, a new raft & frame on it's first outing is always a work in progress to some extent. How did your friend achieve a 2/3 1/3 oar balance on a 60 inch frame with 9 foot oars, without tilting his towers out a bit?
That's good. I tried to get a torque spec from Nrs but to no avail. I've heard of the ubolt snapping if over torqued. I guess worse would be a lowpro cracking.

He had 8.5 to start with, they were on his stern frame. He setup his frame to fit his boat. He then realized he needed the 8" towers (sits on a frontier play drybox). Then to get the oar in the water at his rowing height he added 9' oars

I dont think the 1:3 ratio is a rigid goal, more a target. Everyone's rowing style and strength vary. You trade off stroke for power and balance on the oars. I think the new cataract shafts he got should help in the balance/fatigue area because they are a few lbs lighter

Its a 13' self bailer. Even fully loaded its a cinch to row. Me and my other catboat buddy call it a pool toy

I run a 72" nrs frame with 11' cataract oars. 10' felt a bit too short--- like i needed my arms too high to dig. I've since realized that guys with 10' oars suffer from stroke envy
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Old 04-26-2013   #465
 
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Sandy, Utah
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Originally Posted by Avatard View Post
That's good. I tried to get a torque spec from Nrs but to no avail. I've heard of the ubolt snapping if over torqued. I guess worse would be a lowpro cracking.

He had 8.5 to start with, they were on his stern frame. He setup his frame to fit his boat. He then realized he needed the 8" towers (sits on a frontier play drybox). Then to get the oar in the water at his rowing height he added 9' oars

I dont think the 1:3 ratio is a rigid goal, more a target. Everyone's rowing style and strength vary. You trade off stroke for power and balance on the oars. I think the new cataract shafts he got should help in the balance/fatigue area because they are a few lbs lighter

Its a 13' self bailer. Even fully loaded its a cinch to row. Me and my other catboat buddy call it a pool toy

I run a 72" nrs frame with 11' cataract oars. 10' felt a bit too short--- like i needed my arms too high to dig. I've since realized that guys with 10' oars suffer from stroke envy
Yep. I could tell, even just sitting in the garage, that in order to get the oars in the water for a good stroke, I was going to have a problem with the 8 ft. oars. So I went with taller towers to get more lean & width, then played with the longer oars until they felt right. Since I was able to easily return the 8 ft. oars to backcountry.com, I got the 8.5 oars. I have been through all this with my cat when I changed my seating arrangement, so I knew the problem that short oars can cause.
I have a feeling that my "Little Blue" will be dubbed the pool toy next week. Especially up next to my friend's 18 ft. Hyside (shakedown before Grand Canyon). But the water level is pretty low, and we have lots of boats to spread out the gear, so it seemed like the perfect opportunity to give this new little raft a tryout. A raft....holy crap.....Cataraftgirl has gone to the dark side
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Old 04-26-2013   #466
 
Redmond, Oregon
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Originally Posted by Avatard View Post
............
I run a 72" nrs frame with 11' cataract oars. 10' felt a bit too short--- like i needed my arms too high to dig. I've since realized that guys with 10' oars suffer from stroke envy
Is there, should there be a different formula or fudging of math in determining oar length/set up between Cats and Rafts?
All other things like height above water and crew being equal.

I'm thinking that part of the reason the smooth bottom boats do so well with really long oars is because of their limited turbulence compared with a self bailer. That its not just that they expect greater performance.
But that shouldn't be the case with Catarafts.

Is there a general rule that one can go with different sized oars on a Cat?
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Old 04-26-2013   #467
 
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portland, Oregon
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I think we need to take this thread elsewhere. The natives want to see porn

I think there is too much variation to come up with a unifying equation. Einstein tried but never could. When you say all things equal there is easily a 8" variation in where a comfortable rowing oar position is. Without taking into account tower, locks, tube size, boat loading, etc

RaftGirl? gasp!
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Old 04-26-2013   #468
 
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Sandy, Utah
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I will post some raft porn after next week's trip. I totally agree about the variables in frame configuration and oars. Each person is different, and I have learned the hard way that one little change in the equation (higher or lower seat) can throw everything into turmoil.

To geobucket .... digging your little orange torpedo!

To BilloutWest .... there is no one answer, and you will blow a blood vessel in your head by trying to figure it out. Get a boat, get a frame, get some oars, and spend all winter with it in your garage (or living room) trying to make it all work to your liking. Then put it all in the river, and start tweaking it yet again. This is the life of a river rat.
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Old 04-26-2013   #469
 
Redmond, Oregon
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Originally Posted by cataraftgirl View Post

To BilloutWest .... there is no one answer, and you will blow a blood vessel in your head by trying to figure it out. Get a boat, get a frame, get some oars, and spend all winter with it in your garage (or living room) trying to make it all work to your liking. Then put it all in the river, and start tweaking it yet again. This is the life of a river rat.
Einstein will be proven right.
The theory of Chaos be damed.

I've started a new thread asking what works for each person ........
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Old 04-27-2013   #470
 
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durango, Colorado
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I may have jumped in too late. too much work this time of the year. However, In this whole discussion, I did not see what I consider the main issue. That issue is geometry as it relates to handle height and how handle height relates to the length of the oarsman's torso length. In this image there is a study about which size of oar to use. One can see that the 8 ft oar is out of the water a little more than the 8.5 ft oar. so the 8 ft oar would be for a taller person, and the 8.5 for a shorter person. You could get some relief by rotating these SHORT NRS oar towers ourward, but you would need to use cobra oar locks if you go to far because of the pinch effect mentioned earlier. This is on a 2 person framless cataraft We call a Culebra. Of course I would choose a frameless cat to put a frame on, and turn it into a 1 person boat. This is a computer model of that system.


Now everyone on this thread seems to have way too much time on their hands. Therefore if you want to see the 3D image of this model, that you can spin around zoom in and out of, and check out all the fine details of construction, (which by the way is how we get customers to collaborate with us to build better products ), You will need to read the information at the top of the page and follow the instructions on how to download Edrawings (a free viewer for edrawing files) and then click on the file in the middle column of the table. There are lots of files here, so you can see all kinds of configurations that we have already built on the Culebra format with Jpegs in the left column.

go to the culebra edrawings table site.

Now just a little more about the big issue on oar geometry. It is my observation that the difference between a crappy Cataraft rig, and a good rig can be as simple as oar handle geometry. If the oar handles are above your shoulders, it is hard to push stroke a cat. If you forearms are almost level, then that is the easiest most ergonomic way to push stroke a cat. The problem is varying gear loads. So as the cat gets lighter (on a Grand trip for instance) The oar handles come up, and you correspondingly got stronger during the trip. So how to deal with this on the river? When I get to Lees Ferry, I have some wooden blocks to "jack" up my seat. Before I go, I try to figure out how much draft I will have. That is where this table comes in handy. but obviously you are not going to weigh all the stuff you are going to put on the boat. But experience will tell you about how much draft a cat will have for a given trip. 10 inches of draft at the start of a Grand trip with 10 cases of beer. Is not out of the question for a Daddy cat. Try to rig your cat with the heaviest load where your forearms are horizontal with the blade fully in the water. Then as the boat gets lighter, you will probably not even notice a difference, because you are getting stronger too.

Hope this helps. I may not get back to reply any time soon there is way too much to do.
Jack
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