Current Estimates

I recently purchased my first boat, and I am anxious to experience some new water here in Illinois. Currently I’m kayaking on my own, so current strength is an issue. I’ve been out on the Fox River, where the current is minimal in most places at this time of year (and with our current lack of rainfall), so going upstream and back isn’t too bad.

Svob lists current rates as the drop in elevation per mile (e.g. 0.9ft per mile). I was wondering if anyone knew at what drop in elevation would upstream paddling become difficult/impossible. I should mention that I do not consider myself a strong paddler.

Thanks for any advice.

Tim B.

Fox Paddle
Where on the Fox are you paddling? I’ve been known to haunt the section between Montgomery and Yorkville.


There is no fixed relationship …

– Last Updated: Sep-03-08 10:28 PM EST –

...between current speed and gradient. There are many other factors affecting current speed including the size of the river, volume of flow and the nature of the river bed. Easily seen evidence of this is that a river in flood flows much faster than a river at low level, even though the gradient is the same in both cases.

The best thing to do is learn by trial and error, which is pretty safe if you paddle upstream first so you can return going downstream. Just don't do anything stupid like launch in swift water that you don't know for sure that you can handle (including being certain of your ability to avoid obstacles), and you will be fine.

Next, find some paddling friends so you can run shuttles and eventually tackle faster water.

Upstream first
Always paddle upstream first as far as you can handle then when you’re tired you can paddle leisurely back to your take out spot. There are techniques for paddling against a strong current - mainly knowing how to read a river. The inside edge of almost every turn in a river usually has a back current or at least a much reduced current. The current near the banks for straight sections of the river usually have less current. In general if you watch the river closely you can see where the current is minimal. Watch the river closely and you can travel several miles up a river with an average 3 to 5 mph current.

The current strength may become …

– Last Updated: Sep-04-08 6:51 PM EST –

...... much stronger in shallower areas , even when near shore .

This is confirmed by wading in a river .
When wading , one will move through different depths from , ankle deep to about chest deep .
In most all of my experiences , from the butt on down the water strength/pressure becomes greater as it gets shallower . From the butt on up , the water strength/pressure becomes less as it deepens .

It is true that normally the shore line reach usually has less strength/pressure . And as said the inside of a bend is usually slower with less pressure as the bend developes into the eddy section , but the inside of a bend will be faster than the outside until the eddy section .

As flowing water moves around an object (rocks/boulders) or moves over deeper to shallower bottom contours , the current becomes faster and exerts more pressure (or resistence to upstream paddling) . I believe this is due to the water volumn attempting to neutrilize pressure in the mentioned areas . The current speeds up "reducing" head pressure over these areas but usually not enough to be equal to the deeper section pushing it , therefore remains a stronger pressure (against the paddler) until relieved back to a deeper section simular to what it was before it ran shallower or met the boulder .

Sometimes the flowing water backs or piles up , as it travels from a steeper section to a less steep section . This can cause a wave or swell , where the water backs up . Other simular cases of this are when the flow meets a boulder or bridge piling . The water builds up (piles) on the upstream side and creates a trough on the downstream side . Respectively , higher and lower pressure areas .

It's all about "pressure" , which may often be wittnessed as "water speed" , but not nessasarily always water speed .

As for how fast a water speed is doable upstream , in our tandem canoe with both of us digging in , about 10 mph. brings us to crawl or near stop ..

That means you can paddle 10 mph…
… in water with no current. Congratulations! Even in a fast tandem canoe, that’s an amazing feat I’ve never witnessed before.

I think he missed a decimal point.

At 2 mph
I can make some decent headway. At 3, I can still find a way upstream. At 4mph, we are talking a lot of work to make way upstream. However, I can paddle 5 on flat water. But something about the moving water makes progress pretty tough above 4. Probably because the average speed of the water is about four, but there are micro currents running faster or slower. Water flowing 4 or so usually is not very deep around these parts. So you cannot plant your paddle deeply to get the good bite. And all you need to do is bounce off the bottom once, and round you go and loose all gain you made the last three minutes.

With practice though, you will learn to recongize very small eddies and any little current change you can take advantage of. You will tend to weave your way upstream rather than aim at a point and go. You can charge up some pretty good runs by sneaking up behind the rocks while gaining speed then scooting across the pressure area quickly while you still have momentum, to get a grip on the upstream side and seek your next slack area. I find it best to plan several of these slack areas in a row instead of negotiate one and then try to make a plan. That just doesn’t work in most cases.

You think my estimate is …
… a bit too fast , huh ??

You could be correct ?? My estimate was taken from a PWC river patrol who was intercepting downstream paddlers on the Yough . I’m guessing he had a speedometer or a better grasp of the currents speed than I .

We had pushed as far upstream as we could and then ferried from one side to the other a couple times for practice , then landed on shore to rest .

When the PWC came by intercepting some downstream paddlers , I asked him if he thought the current was moving around 10 mph. , he said “at least that” .

These were the spring waters filling the Yough Res. on the MD. side , running out of Friendsville .

I suppose it would easy enough to put out a simple pitot tube speed gauge in the water to check current speed , but have never done that in a canoe .

So , tell how do others determine the currents speed ?? I’m pretty certain we can reach near 10 mph for a short distance , but I could be mistaken , just don’t think I am …

I would think in general …
… a steeper gradiant , “always” means the water is moving faster !! Although that same piece of water under higher and lower levels will probably have slightly different current speeds .

But steeper means faster , so the grade gradiant is a good indicator of what to expect .

A general rule of thumb for determining water speed is between 14.5’-15’ per second is around 10 mph .

An avg. length of a canoe …

10mph is about a 3:44/km pace. That’s borderline elite for an Olympic C2.

I would agree about that as being …

– Last Updated: Sep-05-08 8:09 PM EST –

....... an Olympic pace .

But I have not implied that it is sustainable for us . To the contrary , I have said it was "doable" (as an estimate) for a brief time .

Actually I believe I said that's is where we have come to halt and then rested . Not sustained .

So in this sense I have said (as an estimate) , that I believe we can reach about 10 mph. for brief period of time .

Is that really not a possibility for any (normal) tandem paddle team ?? Not a special boat , not high tech. paddlers , just digging in for all you got until you poop out (again , a breif period of time).

If 10 mph. is simply not attainable , then what speed is the max. possible at peak (tandem crew) ??

ps., I am very used to heavy work and a hard drive when required . She is as well capable of some hard and tough paddling . So we are strong if that makes any difference ..

Acually at a liesurly pace (in cruise) , I'm pretty certain we cover at least half the length of the canoe per second (that's about 8'-5") ..

the spedometers in pwc(jetskis)…
are often “off” by a few mph. if you want a true reading of your speed, use a gps device.

You’ve heard of “hitting the wall”?

– Last Updated: Sep-05-08 9:59 PM EST –

"Hitting the wall" is a term that gets used a lot by people on these boards to describe the feeling of pushing their boat to a speed where they just can't make it go any faster. With a general-purpose canoe, if you keep increasing your speed you will eventually reach a point where each additional fraction of a mile per hour requires an extraordinary amount of additional power. This speed corresponds pretty well with the calculated hull speed for the boat. Racing canoes are much more forgiving in the manner in which they "hit the wall", making it easier to push them faster than the theoretical hull speed, and the same is true of long, skinny kayaks and rowing shells, but good luck making a regular canoe go faster than that. Hull speed for a 15-foot boat is 6.0 mph, and for a 17 footer is 6.3 mph. I can't reach hull speed in a solo canoe due to the need for correction on every stroke (I don't do sit-and-switch paddling), but I know that it can be done more easily in a tandem. I can push each of my rowboats until they "hit the wall", and when that happens, the GPS pegs the speed at within 0.1 to 0.2 mph of the calculated hull speed. Ask anyone who's gone tripping with me when I've used the guide-boat if they think any standard canoe could be paddled faster than I can make that boat go.

To go faster than hull speed (6.0 mph) in my guide-boat, I have to be going downwind and riding on the face of a pretty big wave. I've gone as fast as 13 mph when surfing on a wave, and at that speed the spray is flying off the bow and it becomes quite a trick to maintain control. The slightest little yaw can evolve into a sharp turn which will scrub off all that speed like slamming on the brakes and could even toss you over the side. I've learned to control the boat so that doesn't happen, but it's not something that you would ever experience under normal paddle or oar power. Even when surfing at 9 mph there's a bit of spray flying off the bow so it looks as if a small outboard motor is pushing me. It looks impressive, but when surfing a wave, the boat is essentially sledding downhill and gravity is supplying most of the power. I consider 10 mph to be a pretty good surfing run, a speed which is nearly twice as fast as I can row.

Your "leasurely pace" of roughly 8.5 feet per second equals 5.8 mph, and that's really flying by anyone's standards. I suggest you borrow a GPS or time yourself over a *known* distance and report back with your results.

Sounds reasonable …
… I am a curious now just how close my estimates have been . Not just the 10 mph. max. , but in all phases . I think I will try to find some different ways to take some “accurate” measurements under different circumstances while using the canoe .

I will over time let you know what they revealed .

Don’t get me wrong , I’ve taken general estimates not trying to be exactly precise , but perhaps they should be refined due to seemingly unanimous GPS use for avg. and max. speed calcs. .

I’m not unfamiliar with GPS , although I do not own one .

I remember when GPS was just starting to become a tool for general aviation , and when finally the day came that it was approved for the landing segment of IFR flights (all the way to wheels down as opposed to just enroute) . But that GPS unit was a very expensive instrument and still is because of it’s accuracy , unlike the handheld or auto units that are in-expensive and good for aprox. location status …

I have always used short course distance measurements to determine max. potential and avg. “no problem” effort required . That has high probabilty of error , just not extremem error when performed seriously .

I’ve never felt the need to be highly pecise about such things when in a canoe , just close has always seemed to fill the blanks for my needs .

GBG , sounds like you are telling me my canoe hull should peak at about 6 mph. give or take . That’s hard to believe . Even more so since I think I’m covering at least half the length of my canoe in a second when in cruise mode ??