Jet ferry on wave face
GBG, that’s a nice explanation of the physics of an upstream ferry from slower current into a faster current.
When I think of a “real” jet ferry, it’s in whitewater with the additional component of an upstream wave face. The classic situation is ferrying upstream across a sharp current differential line (most usually an eddy line) on the upstream face of a standing wave. If the wave has the right shape and length, gravity will keep the boat on the upstream wave face and the boat won’t begin to drift downstream with the current. With good initial momentum, you can jet ferry completely laterally to an adjacent mid-river or bank eddy at high speed using just a downstream heel and a static high brace draw. Blast!!!
Don’t know the Black River…
but looking at the gage, it must have been flowing pretty well on the 17th when the OP was out.
http://waterdata.usgs.gov/nwis/dv?cb_00060=on&format=gif_default&site_no=04260500&referred_module=sw&period=10&begin_date=2013-06-20&end_date=2014-06-20
Looks like it peaked at 9000 on the 16th, and was still running round 8500 on the 17th. That quick increase in volume is certainly a red flag, but looking at some pictures, it also looks like a river that can handle large volumes of water.
http://www.panoramio.com/photo/39067487
At 6.5 feet, it was still a long way from flood stage (10 feet) or the peak recorded flow (55000 - yikes).
It actually reminds me of my local river the Blackstone, which is also dam controlled and subject to relatively quick changes in flow. The Blackstone actually gets easier at higher water levels, although a mistake could result in a pretty long swim.
Intersting excersize, but it doesn’t change any of the recomnendations above – don’t paddle alone, don’t paddle rivers you don’t know, and get some training.
Looks like there is a beautiful waterfall on the Black River . Anyone know anthing about it.
http://media-cdn.tripadvisor.com/media/photo-s/01/56/ca/51/black-river.jpg
Jet Ferry on the Shepaug
You can see daggermat’s son Aaron do a hanging draw ferry at about 00:37 in this video:
http://vimeo.com/8213852
Just a slight lean on the way across.
Hard to believe that was 6 years ago – time flies.
Where not to learn how to paddle safely?
Reading internet forums.
Physics of Ferrying
– Last Updated: Jun-22-14 1:23 PM EST –
Nearly all the classic explanations I've seen dealing with the interaction between a boat's direction of travel and the current involve the boat moving at a right angle to the current and thereby crossing at a downstream angle. Too bad they never use an example that's directly applicable to what a paddler is most likely to be attempting. The "straight across" travel direction is pretty easy to grasp, but for some reason, what I've often found when talking about these things is that once you introduce an upstream angle of propulsion, many people completely lose sight of the fact that the boat really IS just traveling forward through the water in the same manner as any other time, with or without current. What I'd love to see someone do to demonstrate this, would be to video a boat's progress at various angles to the current, including typical ferrying, using both a stationary overhead camera and an overhead camera that actually follows the current and maintains a discrete parcel of the water within the frame of view during the whole exercise. Superimposing the "still-water" frame of reference onto a moving-water situation would be the perfect way to clarify what I was trying - and totally failing - to convey earlier to Celia. The overhead-camera method would be an expensive undertaking, but it could also be conveyed with modern computer graphics really easily (not by me though).
Nearly everyone understands the principle of the current adding to your "real" travel speed when you paddle downstream, and subtracting from your "real" travel speed when paddling upstream, but the concept that does NOT makes sense to a lot of folks is that the same principles apply to any other direction of travel within a current as well, with the only difference being that trigonometry is involved in figuring out the true speed and direction instead of just addition/subtraction. When one understands what's going on, they will realize why there's no alteration of the hydrodynamics between boat and hull (and thus no edging needed) when on any cross-current heading, except of course to adjust for sudden bursts of new current velocity that are encountered for various reasons (and those are common enough for us paddlers to potentially distract a person from thinking about the general principles of going cross-current).
I just looked for a video explaining this better than I can, and found a pretty good one on my first try.
http://www.youtube.com/watch?v=6fVz1XoPoNU
There's not actually anything here to emphasis the fact that a boat (or swimmer) is moving straight forward through the water that supports it (or him/her in the case of the swimmer), no matter which direction it is propelling itself (himself/herself) in relation to the current, but to anyone who actually understands the principle being explained, that fact will be abundantly clear. Now, if only his final example had made the swimmer as fast as a paddler, that example would have illustrated a perfect ferry.
One thing that's interesting if you follow the math in this video, is that a ferry is not the fastest way to cross a river, even though most people automatically assume that it is. It's the shortest in terms of distance traveled relative to the fixed river bottom, but the distance traveled through the water is longer than it needs to be (a shortcut - no math needed - to determine distance paddled through the water is to pretend there's no current and just extend the line along the initial path until it reaches the opposite bank, and measure the length of it). To cross in the shortest period of time, you'd need to choose the path that involves the shortest distance of through-the-water propulsion, and that is to aim straight for the opposite bank and then end up somewhere downstream of your original target (in that case, the actual distance traveled would be greater, but the *time* of travel, and the distance of propelling oneself through the water, would be least).
Jet-Ferry on Standing Wave
– Last Updated: Jun-22-14 3:03 PM EST –
That's a type of fun I've mainly played with on a smaller scale, as smaller waves are what I usually see (had a near-disaster doing it on a big wave once, but somehow I stayed upright). It's interesting that you describe the physics of ferrying across the face of a wave in the way that you do. I've lost my best surfing/ferrying photos, but for one shot out of a series taken on one tiny wave, I explained what was going on in a very similar manner to what you did just now. The only difference was that I mentioned the hole behind a little drop in the same way you spoke of the face of the wave (in my example, the hole was tiny (microscopic by whitewater standards), but getting out of it in the downstream direction was "uphill" if the boat was angled enough to get enough of the hull into it, so the principle was the same).
http://tinyurl.com/k5juoxe
To mitigate…
I likely missed the upstream v downstream part of what the OPer had to do, and that may have been creating confusion. I got so distracted by trying to get a direct answer out of guideboatguy rather than a protracted lecture on how to ferry that I lost track of some of the original issues.
The original issue was “edging”
– Last Updated: Jun-22-14 1:50 PM EST –
I tried to explain why edging isn't needed during simple situations like this, and used crossing the current as an example since that's what the OP needed to do to get to the riverbank. When your reply indicated that you still thought edging was needed, I tried a more-detailed approach - details you simply weren't ready to listen to.
The downstream lean Glen refers to here is needed when punching into a zone of stronger flow while making the turn, or if there's already an upstream component to the boat's velocity at the start of the turn, but not for the ferry itself, and not if the turn is simply done by paddling in a tight circle (same as you'd do on flatwater) while drifting along. That's why I said edging need not be the solution.
Talking simply about turning the boat
Virtually all boats, especially a flatwater design, will turn more easily when heeled close to the gunwale (=edge) to free the stems and shorten the waterline. This is so in current or still water.
The lean (=heel=edge) I’m talking about is simply to help turn the Pungo into the upstream ferry angle. Once at the proper ferry angle, heeling (edging) may not be necessary to effect the ferry.
Yes
– Last Updated: Jun-22-14 4:01 PM EST –
I understand that, and in fact, the situation I mentioned about paddling upstream and suddenly turning sharply, thus needing to lean downstream, is virtually the same as when paddling very fast on still water and initiating the very same sharp turn (I'll leave out the explanatory details this time). And I understand the idea of lifting the stems to make any such turn happen quicker.
Still, making a sharp turn happen slowly while drifting, or slowly pivoting the boat with simple sweep strokes while drifting, requires no such lean. It's the fact that the OP could have burned up 100 feet of downstream drift while getting turned to the proper heading while doing it this way that made the original backferry idea so appealing (that was my reasoning anyway, and I wonder if that was your reasoning for bringing up that method in the first place). In any case, some of Celia's replies made it clear that she believes that any paddling while at an angle to the current requires a constant lean, so that's why I tried to differentiate being at equilibrium with the current and not being, because during a normal ferry (or when paddling in any other direction but not across eddy lines) one is at equilibrium with the current.
My original point was that the mere fact that a boat can't easily be edged or heeled doesn't *prevent* a person from making a nice, clean maneuver, and it sure need not be the reason the OP got "trapped" in the main flow for so long, unable to escape. Being in a boat that isn't easy to lean just means that some slower process must be used. An experienced paddler in that same situation, in that same Pungo, could have smoothly exited to the river bank in a few seconds. You could have done it, I could have done it, and so could plenty of others (Celia was putting way too much blame on the boat). And there are plenty of good paddlers who can make a rec kayak lean "enough" to help a lot.
Bu you hit the nail on the head (for the second time now) in saying this was the wrong situation for the OP to try out this stuff (whatever particular trick one might choose), and I assume you mean regardless of what boat is being used.
The story reminded me of something
– Last Updated: Jun-22-14 4:31 PM EST –
This is of no great importance, but some might remember that last spring, someone here posted a link to a video that a guy made on a little creek near Chicago, right after the area had gone through some really torrential, record-setting rainstorms. He used a head-mounted camera to record his story, launching on the flooded creek and (apparently) trying out his new rec kayak for the first time. One thing he said as he narrated the beginning of the trip was that he knew next to nothing about paddling, but that he hoped that before the trip was over, his skill level would be a lot better. Yeah, bad idea.
The creek was way up into the trees, and his camera recorded several instances of him just not knowing what to do, but "getting by". Eventually he got his boat stuck in a strainer (a perfectly avoidable strainer - not that it would have made sense to be on that creek in those conditions), and managed to work his way along that fallen tree to climb out on shore (it looked like the boat was non-recoverable, at least until the creek went down).
The guy who posted the video made it really clear that he had had no idea what he was getting into, that he easily could have died, and that the whole idea of going on that creek on that day had been a huge mistake. Still, a bunch of people posted really insulting comments, comments that didn't take into account what the guy really wanted to show - the fact that his own ignorance got him into trouble. That was too bad, because even though at first he replied to them by emphasizing that he was not too proud to show how stupid he had been and that he'd been lucky to escape unhurt and alive, eventually the stream of personal insults caused him to give up and he took it down. I thought it was the kind of video that someone, somewhere, might benefit from, and thought that it was commendable that the poster publicly recognized the fact that he hadn't known enough to even know what he didn't know.
This in a reply at least four days ago
"Edging or not (sounds like some portion of the OPer’s path may have been amenable to a jet ferry), the paddler still has to control the angle of the boat to the current for a ferry. The Pungo has no grip to do that decently without some nasty action on the paddler’s knee caps. "
Note the “or not” part. I really did mean that. I don’t think you ever noticed it.
Some comments,
First of all, the big debate about edging and various ferries is somewhat irrelevant. This is an inexperienced boater who probably would feel very uncomfortable trying to edge on purpose to accomplish anything other than keeping from tipping over (Only advice would be to always lean downstream, not upstream, when in heavy current, if your boat gets anywhere near crossways to the current and is going slower than the current.) As for ferrying, it’s really pretty simple, and the backferry is pretty easy to do in a Pungo with a double bladed paddle. In the simplest explanation, you’re backpaddling to make the boat go slower than the current, and putting the boat at an angle so that the current hits the side of the boat that is away from the sideways direction you want to go, and pushes the boat in that direction. Depending upon the rate of flow and paddling speed, the current will either be moving you sideways relative to the direction of flow while you’re going downstream more slowly than the current, or while you’re actually holding steady or even going upstream if the current is slow enough and your backpaddling speed fast enough. Spinning around to do an upstream forward ferry may or may not work better, but in fast, heavy current, the act of spinning the boat around in itself can be dangerous for the inexperienced.
River gauges…the most important piece of info to look at is the MEDIAN flow for that date, shown in the flow in cubic feet per second table and by the little triangles in the flow graph. If the river is flowing considerably more water than the median, it’s high and faster than normal. Then look at the 75th percentile flow in that same table. If the river is flowing around that or higher, it’s QUITE high, and probably getting dangerous.