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Thread: High-centered on a rock...

  1. #1
    Member 6XLeech's Avatar
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    Default High-centered on a rock...

    Holy cow... and never in shallow water it seems! For me, it's been catarafts.

    Fortunately, last time - my brother was on the oars. We were on the Goodnews River, our first flyout float. The Goodnews is a gentle river mostly, with plenty of width and depth and very few rocks. Very few. We rocked and rocked with the oars. Tried poling off the bottom without success, then shifted weight and rocked some more. Thirty minutes I bet.

    Two years ago, it was a friend in his heavily loaded 16-foot cat on the Upper Gulakana River -- high water and that one rock. When a cat is stuck, it's can really be stuck good. Always seems to be this one rock in deep water. What can you do? From another raft, we got a rope and some guys to shore and pulled...awhile.

    This ever happen to anyone else?

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    Smile Point-Loading

    One characteristic of a CataRaft design is that it will point load on a hazard like the 'high-centering' you described or this can happen on parts of the tubes clean out of the water getting stuck on a log, knob, boulder etc.

    While in your scenario, you likely have a few things going on... one important bit of physics is that much of the boat weight + energy force of the current is bearing (read as transferring load) on the higher friction (read as traction point) rock --- meanwhile the rest of the boat dynamic is very little surface tension (read this a surfing as water passes downstream of the boat).

    As you said - this can be a real dilemma under certain circumstances where the water is too deep, to fast, other hazards lurk just dealing with the pickle you could be in.

    First thing in a CataRaft if this happens:
    (beyond the watch were you are going lol.)
    While a point load can be worrisome, tiresome, pain-in the-butt-some... This is also a quality in itself of the CataRaft design. What do I mean? The fact that a CataRaft has very little surface tension compared with Self-Bailing rafts means that if you float into a hazard (something solid like rocks and wood or liquid like hydraulic keepers) you are far less likely to take on water, loose performance, or flip. In effect - I'm saying what hangs you up does in fact handily up margin of error and adds to safety.... in turn also getting you through tougher situations confidently and easier. Feel good that you are in a CataRaft #1 here!

    Second thing is that many times upon a point load the CataRaft will give you a little time to establish the immediate hazard that has you hung-up, form some strategies, then actually start doing something about it. In your case sounds like plenty of time! So do not stress mentally blow yourself out in no time physically. #2 is See, Assess, then put strategy to work. If you have others in the boat communicate clearly what you plan to do and what may be expected of them to cooperate if needed.

    Like you said too deep, and tried poling.... Generally this is often a bad idea and bad form. Good way to loose oars! Good way to get vaulted out! Good way to break stuff like the oar or bashing stuff and folks on the boat! Good way in get hurt yourself! Very limited lift or power often waste of time and energy! BAD FORM!!!

    This also goes for most arm and leg push-offs with loaded rafts in this situation... Bad Form!

    Most successful way to get off a point loading is attempting to find just the right spin free dynamic... like a sweet spot... work with the river and feel where you can take advantage... sort of the teasing the currents power trend (also what's keeping you there by the way) and levering off in the same sequence of moves. Often this means dipping your blades in active water that is doing something for you in addition to maximizing your own row station power zone --- such as face upstream with your body reaching downstream of a rock hazard holding steady or pushing against it (this water is recirculating up-stream) and holding steady or pulling well upstream with the other oar (water is flowing downstream).

    Another way is to slowly coax the point-loading further away from its holding power and gain progressive boat real-estate from the hazard. Key is go slow even if a Baptism looks possible. People with panic that try to work it too quickly almost always burn out tired in no time and may make things worse.

    Occasionally you can use one point load as a strategic solution to lessen the problematic point. An alignment of sorts and lesser of two evils.

    You talked about more or less a pinned situation of no gettin' 'er done unless you exit the boat and devise a haul with rope-line... be it in-line man-power, Z-Drags, and other forms force multipliers. Not a great situation to be in, yet a darn good thing to know how to deal with and be equipped having the proper rescue gear. I won't get into how you 'wet exit' your raft and how to set traverses, wall-hauls, and Z-drags... that is for another discussion, or we can show you a practical demo and the right stuff to have at our shop.

    Hope this helps -

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    webmaster Michael Strahan's Avatar
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    Default Agreed...

    I agree with Brian on this one. Usually the best course is to dip one or both oar blades in the water and use the hydraulics of the river to spin the boat one way or the other, to crawl your way off the obstacle. You can also change the center of gravity of your boat by having your passengers move to a place in the boat that lifts the part of the tubes in contact with the rock, and you can even have passengers bounce up and down to assist (assuming of course that you can do so without endangering anyone). In some situations I have dipped each oar sequentially, and the boat swayed back and forth slightly, with the current pushing you off an inch or so at a time.

    Prevention is better than cure, though. Watch where you're going and keep your tubes properly inflated. They are less likely to conform to an obstacle if they're properly inflated.

    If you cannot get the boat off the obstacle, you can send a swimmer ashore (yeah, I know...). Once the guy recovers from hypothermia, you can toss him a line and perhaps he can pull the boat free while you assist with the oars. If not, you can start unloading, using carabiners and the bow line to float gear ashore to your partner. Hopefully if you move enough weight off of the wedged area, you can work the boat free.

    Lots of ways to do this; hopefully that helps!

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    Member bigmtn's Avatar
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    Default unstuck

    I ve got some water experience but dont consider myself a overly experienced rafter but ive been using a drift bag to help pull off of rocks if high centered. So far Ive had no troubles using this method. Obviously stonger currents can pose a problem once free but I always am able to cut my sea anchor free and retrieve it down srteam if things get exciting. Any one have any cautions or concerns they have on this method???

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    Default Drift Devices

    Drift bags and buckets do work... Most are really not intended to apply enough 'traction' and tension to work your self off more significant, difficult situations. Most of these are not strong enough. Then there are the issues of disposables in the river (like the pickle-bucket application).

    It will 'double duty' for some scenarios (so good creativity on your part), nevertheless a drift device can quickly, easily, and surprisingly/dangerously become a mid-current anchor system.

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    Default

    Great thread. At the end of the day the success probably comes from moving the weight or center of gravity... but of course their's lots of variables depending on flow, depth and closeness to shore. I too worry about breaking an oar or blade when trying to pole myself off. Hardest part for me as a rookie paddler is just to remain calm and rational.

    The stuck cataraft in the following vid is 'not what to do'.

    http://www.youtube.com/watch?v=Zft4RKnULIQ

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    Default

    That YouTube video was fun, but I kept thinking one of those guys were going to get swept under the boat. Why didn't they just jump on the downstream tube first thing? I would think that the obvious choice.

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    Member 6XLeech's Avatar
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    Default Video illlustrates it all...

    Great explanations, all...thank you very much.

    In that video, if I understand what you guys are saying, the 2 guys in that yellow cataraft could have:
    1. Tried to spin the raft by rowing in opposite directions with oars
    2. Pulled an oar out of its oarlock, then used the blade to apply water pressure on the back (near) end of the upstream pontoon - so that the brisk current would spin the raft off the rock
    3. Shifted cargo/crew weight away from the rock
    4. Deployed a bucket or drift bag (if available) on a line downstream (there was a good thread on this type of technique in the power boating forum last winter) away from the rock to spin the raft off

    Brian --thanks for explaining the physics...hydraulics? - about high-centering, incld surface tension, and the point that the one good thing you have going in this situation is time...time to think...time to plan...

    Jim-- Agree - watching the clip gspd750 posted reminded me of a tragic boating death in Florida years ago, when a woman jumped off a boat too soon as it approached the beach. She was swept under a barge downstream by the powerful current in a narrow pass. Apparently she panicked in the water and so, drowned. Watching that Government Rapids video - reminded me that surprises in the water are best avoided in this situation.

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    Smile

    Quote Originally Posted by 6XLeech View Post
    Great explanations, all...thank you very much.

    In that video, if I understand what you guys are saying, the 2 guys in that yellow cataraft could have:
    1. Tried to spin the raft by rowing in opposite directions with oars
    2. Pulled an oar out of its oarlock, then used the blade to apply water pressure on the back (near) end of the upstream pontoon - so that the brisk current would spin the raft off the rock
    3. Shifted cargo/crew weight away from the rock
    4. Deployed a bucket or drift bag (if available) on a line downstream (there was a good thread on this type of technique in the power boating forum last winter) away from the rock to spin the raft off

    Brian --thanks for explaining the physics...hydraulics? - about high-centering, incld surface tension, and the point that the one good thing you have going in this situation is time...time to think...time to plan...

    Jim-- Agree - watching the clip gspd750 posted reminded me of a tragic boating death in Florida years ago, when a woman jumped off a boat too soon as it approached the beach. She was swept under a barge downstream by the powerful current in a narrow pass. Apparently she panicked in the water and so, drowned. Watching that Government Rapids video - reminded me that surprises in the water are best avoided in this situation.
    6X -

    Your #2 is bad form... the oars do the most good, generate the most power/leverage/control, and have the least threat to loss or injuring somebody by staying in the locks.

    Your #3 sounds good on Crew... but in a more demanding situation moving significant gear around by un-securing it can be a major mistake.

    Your #4 sounds better than it really is... skip the bucket Idea for the most part. While creative it can also be instantaneously disastrous in a truly demanding scenario. Practice with this in an easy setting first - like traction drift your unloaded then loaded raft off the campsite gravel bar.

    Hope this stuff makes sense -

    -------------------------------------------
    This part of my reply to this thread will mostly address the video of the Yellow Cat...

    May sound a bit harsh, however this is not the intent... Just breaking down the "landed on a rock mid-river" sequence.

    A.) The oars-person is clearly 'drifting' aimlessly down the stream.
    B.) Plain to see... Not scanning while reading & running much past his nose, doesn't matter the reason - he simply does not observe any hazard.
    C.) Nonchalant with the oars
    D.) Indecision at the oars and no decisive ferry angle set
    E.) No reaction instantly and instinctively with a power downstream back sweep stroke of the oar while he still had potential spin momentum to take advantage of (in that very direction they got off eventually).
    D.) Not assessing the physics of situations ---> friction on the rock w/ the weight of gravity resting point load on the upstream tube --- offset by the downstream tube buoyancy --- little surface tension w/ resulting surfing action of the CataRaft in an up-steam recirculation directly effecting downstream tube --- not recognizing where the beneficial current is running and fumbling w/ the oars.

    I'm not rippin' on the guy... only trying to give the 411 as it is more or less pretty plain to watch unfold in the video. Fortunately not a big deal, not a real demanding situation, the boat held up to the hang-up, and they had plenty of time with maybe some support by the guy taking the footage.

    Reason and Consequence of A. & B) is likely a combination of inexperience rafting, not knowing the river, not reading the river, and not paying attention therefore landing on the easy to define hazard.

    Reason and Consequence of C. & D) That is the most subjective part of the footage, but is a common mistake made by less experienced paddlers... ask yourself... why is the oars-person being lazy spaghetti noodle at the oars (the whole time!!!) and once nearly on the rock why the early give-it-up on gaining any beneficial hull real-estate away from the rock? Whatever be the case, it is very typical for folks to have mental freeze and show physical lapse facing a close-up impending hazard.

    If the read is wrong... If the Oars are not used productively in the water... If the correct ferry angles are not used... If there is further delay in response time through indecision... If you give up paddling just before you are sitting in hazardville... If you get stuck in hazardville with little practice, instinct, plan, and purpose to get unstuck......... You most generally do end up in a more problematic situation.

    To sum this video up - these guys had a river running style comparable of slouching in front of the video-game --- may well have been eatin' munchies and sipping cokes while lettin' the game come at 'em... That was the oarsman's efforts at best. On good thing tho' - it carried over to their advantage of mellowing out while not doing anything too drastic - this is the best lesson in this video

    What do we learn from the video... not much other than watching this u-tube we gain perspective of a probable downriver event and exhibits that in a CataRaft you have greater margin for error in addition often having way more TIME... the guy recording the sequence was looking to capture somebody possibly getting wet.

    I'd recommend watching 'Lets Get Wet' instructional video plus demo footage of river techniques that also feature hazards and rescue... or taking a hands-on course like our rafting classes (intro 101 through advanced IV) come spring. Also NOVA is involved with a good practical swift-water rescue program that you will get out what you put in.

  10. #10
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    Default Rewriting this script?

    Yellow cat video:
    1. Granted there could be some unseen hazard on river-left, out of camera view that this oarsman was trying to avoid.
    2. But otherwise,...the rock he broached on (at 0:29), looks like one visible from the beginning of the clip, 0:00... or at least 0:14 or so.

    What do you think the latest opportunity for an effective maneuver was?

    I'll guess that, by 0:14-0:17, somewhere in there - I think I would have spun the tail left to set up a downstream ferry and rowed hard...

    Coaches comments?

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    Default

    I can't figure out why he was so far river right. There is nothing obvious in the video that looks like it would force one to be anywhere near there. And sure enough, he gets hung up on a shallow rock near the right bank. Brian is right, this guy is not trying to do anything assertively. He's just letting the boat lead him downstream. Seems plain to me that he has no clue what he is doing, is probably a total newby, and in over his head on a simple rapid.

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    Thumbs up

    Quote Originally Posted by 6XLeech View Post
    Yellow cat video:
    1. Granted there could be some unseen hazard on river-left, out of camera view that this oarsman was trying to avoid.
    2. But otherwise,...the rock he broached on (at 0:29), looks like one visible from the beginning of the clip, 0:00... or at least 0:14 or so.

    What do you think the latest opportunity for an effective maneuver was?

    I'll guess that, by 0:14-0:17, somewhere in there - I think I would have spun the tail left to set up a downstream ferry and rowed hard...

    Coaches comments?
    Yes - just as the yellow cat hangs up --- the free stern section begins to swing downstream... as this swing starts, he should take a full power back sweep with the downstream oar. In effect, very probably spinning off the hazard... also spinning right back to having the bow section leading down river or a getting into a good ferry angle for something else if needed. He would not be using a 'downstream' ferry angle to move off the rock... he would be taking useful advantage of the momentum that starts happening when the stern starts swinging down river.

  13. #13
    Member Erik in AK's Avatar
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    Default

    Brian,
    Thaks for the pics. If I may here's what I see...

    catboat.jpg

    1. The black arrows mark the current and from this pic it appears the boat has come to rest on an eddy slick. Iall liklihood it's slowly drifting river left into the drop in the center-bottom of the frame.

    2. The oarsman is evaluating: oars up, eyes downstream. He appears relaxed so I assume from his posture he's a second or two away from dipping an oar.

    3. This smaller rock might catch the rear of the left tube but it looks like it will clear. The downstream eddy off this rock is contributing to the slick the boat is resting in.

    4. Given that the boat is an 18 footer this about a 6-7 foot standing wave which, in most runs through this spot, will come right between the tubes and get the passenger very wet.

    What I'm gussing the oarsman will do here is...

    -dip the left oar for just a moment to start pulling the rear of the boat left and the right front out of contact with the rock.
    -quickly transition to a double-oar pivot back to the right
    -eat the wave, and as soon as he gets clearance on the right
    -dig with right oar to get the nose downstream while tucking the left oar forward for a push away from possible obstacles on river left

    At least that's what I would do
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