Right Answer, Wrong Question
I’m not asking how to paddle an inside circle.
I’m asking what hull features help a boat carve that inside circle.
I agree that long unrockered hulls don’t carve inside for beans. But neither did my highly rockered Gyramax C1. I could get Clarions Supernova to carve on my onside…barely. Couldn’t do it on my offside at all. My Atom and Slasher carve onside and offside effortlessly. Rocker and hard chines. But so does my Outrage. Still got the rocker but the chines are kind of soft.
Yes the hull carves. You can feel it. It actively resists the opposite turning force from the off center paddle strokes.
But I still don’t know why some do more than others?
Hull carving
This topic is confusing to me and I too struggle to understand. I’m no expert and should probably should stay out of this discussion, but hey, it’s p-net and that’s what we do here.
Understanding the nomenclature will help, for starts.
Inside - is this the paddle side and the side you are leaning down?
Touring kayaks turn away from the side that is leaned down (down means the deck is close to the water). This happens because the water line on the down side is longer than the water line on the upside, so that in essence, the down side is going faster than the up side, causing the kayak to turn. I like to say “hydrodynamic forces” make the boat turn. I know, its all hydrodynamics, but I’ll just call this hydro turning to differentiate it from carving.
Rockered canoes generally turn towards the side that is down (down means the gunwale is closer to the water). I thought this happens because the canoe follows the arc of the rockered hull, and I think this is what you mean by carving. I never considered stern skid, which seems to me to occur only when I stop paddling, as you do going into an eddy.
I can sometimes get longer flatter canoes to behave like a touring kayak, and turn away from the downside.
Only with canoes, I think there is force from the bow wave such that when you lean the boat, a wave forms under the bow on the up side. The boat slides off the wave, turning towards the side that is down. This reinforces carve and it works against “hydro” turning forces.
So it seems to me there are three things contributing to how the boat behaves when heeled: the hydro forces caused by waterline differential, the carving force as the boat trys to track to its rockered shape, and the pushing of the bow wave on the hull. Each different hull likely encounters variations among those three forces when leaned, and therefore behave differently. In fact, I think as you change the amount of lean, you can bring different forces into play. Some boats seem to change the direction that they want to turn in response to different amounts of lean. But this is no help with the original question of how to predict the boats behavior based on the hull characteristic, is it?
Anybody looking for a topic for a thesis? Post here when you are done.
~~Chip
Inside
Is the paddle side and the side that is down as well as the side closest to the center of the circle.
I’m not sure about the skid thing. Seems as though I remember something from “Drill Time” about skidding a turn vs carving a turn. I think the point was they leveled out the heel part way through the turn to skid the stern into place or they maintained the heel to stay on the arc. I’ll have to throw that tape in the VCR and see if I understand it any better now.
best post ever
This grasshopper needs to study this post at length.
Not sure I fully understand inside circle term. Seems like rocker and shallow arch vs shallow vee bottom are factors and maybe stern design…it’s all hull design factors right? And every hull is a different hull at every lean angle?
I’m lucky to have sampled many hulls and one unique hull was the Bluewater Freedom 17 which was actually quick and fast solo as well as tandem and it also spun on a dime and it was a shallow vee with a stern that kicked up like a sailboat’s and easily broke free to skid when turning but still added speed when cruising. The tradeoff was that the initial stability was compromised a bit tandem…boat always moving around a bit under you. I clearly remember the Osprey stern would just whip around and actually feel like it gained momentum with no paddle input at low speed, leaned over…with weight forward. Stern may have 1-2 feet of daylight…or just get very light. In my experience you can’t really force the skid in many shallow vees (Blackhawk Ariel…maybe Independence to some degree, even Blackhawk Zephyr) unless you lean them way over, and even shallow vees with low rocker (Peregrine/Kestrel, Merlin II to some degree) resist super tight inside turns relative to boats with rocker and rounded sides (Fire boats) or boats that can get their tails light (Osprey/Shearwater…easy to move forward and get stern airborne with sliding seat).
In general seems like shallow vees feel like they carve and shallow arches feel more like skidders.
I need to study Charlie’s physics lesson more.
nomenclature
– Last Updated: Apr-18-08 10:18 AM EST –
Hi Chip :
you wrote
Actually the Inside Circle can be two different turns, 1. the Onside Circle and 2. the Offside Circle. The Onside circle is initiated by cross forward stokes to start a turn to the onside (paddle side) followed by a heel to the paddle side and then pure forward strokes (w/o correction). The Offside Circle is initiated by a couple of uncorrected forwards followed by a heel to the offside then crossforward strokes.
You wrote:
Heeling to either side will facilitate a turn once it is initiated. In other words if you initiate a turn to the paddleside and heel to the paddleside the turn will be helped by the heel. If you execute the same turn but heel to the offise the turn will still be to the paddleside and also aided by the heel. So any heeling helps turning. If a hull is traveling perfectly straight ( take the paddle out of the water and it continues straight) then heel the hull it will turn away from the heeled side very time. This is where the heel causes the waterline shape to become differential and cause turning. BTW, it's harder than some might think to get going perfectly straight. If there is any turning influence on a hull such as yaw, a heel will facilitate the turn but only in that direction. This is because a heel reduces the wetted surface and waterline length.
Hope this help, I tried to shorten up a long subject.
Carve vs Skid
– Last Updated: Apr-18-08 11:47 AM EST –
Drilltime is an instructional video for solo whitewater canoeists. It talks about carving as a way to maintain momentum around an arc using all power strokes and no corrections. Then they show some nice overhead footage of a boat carving round a bouy followed by the same boat transitioning from a carve to a skid by leveling out the boat tilt. In the carve, maintained tilt, the boat stays on the arc and is powered around the buoy. In the skid, leveled, the stern slides right around. They talk about using the carve to power into larger eddies and the skid to turn the boat into tighter eddies instead of blowing through (something I do all too often).
At least in that boat (a Dagger Ovation I think) there is a clear difference between carving the inside circle and letting the stern skid.
It makes me think that carving has a lot to do with the keel line under the tilted boat being shaped like a C or maybe a ( with the open side towards the center of the circle.
[Edit Nope I got that bass ackwards. On a hard chined boat the open side of the C would be pointed away from the center. Doh! ]
I suspect that different hulls combine carving with skidding to varying degrees.
correction
In a previous post I copied and commented on some portions of a post from Booztalkin and the copied text did not reproduce in my post. Not sure why, its a computer thing. I could not go in and edit either. Anyhow here’s a second try:
Hi Chip :
you wrote: < Understanding the nomenclature will help, for starts.
Inside - is this the paddle side and the side you are leaning down?
Actually the Inside Circle can be two different turns, 1. the Onside Circle and 2. the Offside Circle. The Onside circle is initiated by cross forward stokes to start a turn to the onside (paddle side) followed by a heel to the paddle side and then pure forward strokes (w/o correction). The Offside Circle is initiated by a couple of uncorrected forwards followed by a heel to the offside then crossforward strokes.
You wrote: < Rockered canoes generally turn towards the side that is down (down means the gunwale is closer to the water). I thought this happens because the canoe follows the arc of the rockered hull, and I think this is what you mean by carving. I never considered stern skid, which seems to me to occur only when I stop paddling, as you do going into an eddy.
I can sometimes get longer flatter canoes to behave like a touring kayak, and turn away from the downside.>
Heeling to either side will facilitate a turn once it is initiated. In other words if you initiate a turn to the paddleside and heel to the paddleside the turn will be helped by the heel. If you execute the same turn but heel to the offside the turn will still be to the paddleside and also aided by the heel. So any heeling helps turning. This is because a heel reduces the wetted surface and waterline length. If a hull is traveling perfectly straight ( take the paddle out of the water and it continues straight) then heel the hull it will turn away from the heeled side every time. BTW, it’s harder than some might think to get going perfectly straight. In this case, the heel causes the waterline shape to become differential and cause turning. If there is any turning influence on a hull such as yaw, a heel will facilitate the turn but only in that direction.
Hope this help, I tried to shorten up a long subject.
it depends
with forward speed most designs ‘want’ to go to the right with a heel to the left and vice versa. Some designs will do this the opposite way though! Can also be different with the amount of heel… Experimenting with your own boat is the only sure way to find that out. But as pagayeur pointed out correctly, it is hard to get going perfectly straight to find out how a hull reacts on heel.
Yup, one of the good ones
– Last Updated: Apr-18-08 11:23 AM EST –
I've caught myself repeating 'peripatetic pivot point' over and over again. I want to be able to say it 'three times, fast', as I suspect this may be a key point.
getting to basics
Sorry Tommy this is not an answer to your question but hopefully will help level the field by providing some background.
The Inside Circle was pushed by Tom Foster as a way for paddlers in WW canoes to understand hull and paddle dynamics and start using them ultimately to paddle straighter.
Tommy C1 is correct, the footprint (when heeled) of different hull designs are different. If you put a “lake canoe” on sand heel it over, then trace it’s footprint you’d see one side is straight and the other a parabola. Water will flow passed the straight side, but pile up on the curved side and force a turn. That is why, all other forces being equal a hull tends to turn away from the heeled side (unless initiated in the other direction first). The footprint on heeled WW hulls can actually be shaped like a crescent and are much more prone to turning.
WW hulls that have little differential rocker or in many cases symmetrical rocker, will continue turning in the direction initiated even when not heeled. In a WW hull, because of its design, a forward stroke should be considered an initiation to the offside and the turn will continue unless stopped ( usually by a correction such as a stern pry or J) and that, more than other hull designs becomes like putting on the brakes. So in a WW hull, correction strokes are used to stop spinning more than for correction and thus very counter-productive. We can take advantage of this tendency with the Inside Circle, which allows for all power strokes and no correction strokes. Eventually a paddler can learn how to finesse these circles into an ever increasing radius and finally go more or less straighter using only power strokes. In a way it works like this: the paddler starts a slight carve to the onside then does forwards w/o those slowing correction strokes, which acts as an offside initiation and the forces off-set each other, resulting in a straighter line with better speed.
The best analogy I can think of is an onside upstream ferry. The current tends to push the bow into an onside turn but this can be offset by power forwards which tend to produce offside direction, resulting in an easy ferry known as a “jet ferry”.
sounds like a very good explanation
– Last Updated: Apr-18-08 11:43 AM EST –
Some years ago I had a good canoeist try to teach me about "the sweet spot" whereby you can paddle a rockered canoe without any correction stroke by finding the right amount of lean. But, trying to teach "the sweet spot" before teaching the inside circle meant that I really didn't get it.
Seems Foster's approach of teaching the inside circle first makes more sense. At least now I "get it" even if I often can't do it.
heels resulting in onside turns ?
Hi Dirk :
I can think of no hull when going perfectly straight that will turn to the heeled side. Having said that, I also have not paddled every hull in the world, so what do I know? I do know that physics suggests turning away from the heeled side when going perfectly straight. Can you enlighten me?
The best test I know is called what many call a “Free Spin” discussed previously. This is where the paddler tries to go perfectly straight at level trim then lifts his paddle from the water, if no influences exist the hull will continue straight, then is heeled to note turning tendencies. As stated, this straightness can be hard to achieve. If there is even the slightest influence on the hull it will turn in that direction when heeled.
stupid pond tricks
Get going straight, head right for another canoe sitting at rest, take your paddle out of the water and do a pure lean turn before hitting the other boat
… well that’s the idea anyway.
a friend with a
hard-chined and deep V-hull kayak showed me once that his boat turned to the heeled side, and so I am convinced now that this is possible with some kind of hulls. Just don’t ask me what design characteristics I can attribute this to…
Yep
Your friend left out one very important element. Some type of initiation to the onside must come first. I prefer an easy ( doesn’t have to be powerful) cross forward ( vs. a prying action) as it keeps forward momentum going. Then do the onside heel. Once the hull starts carving to the onside you can execute pure forward stroke w/o correction and really pick up some speed and power. This results in much better control. The pure forwards need to be timed correctly or the onside spin will take over and you’ll be left just trying to stop the spin instead of going forward.
interesting you mention the timing thing
I’ve found that “timing” of the strokes makes all the difference for me. But until just now, I thought I needed “timing” because of some other unknown-to-me deficiency in technique. To me, the timing thing involves a bit of a pause between strokes.
I have a kayak that does this
Or is it a canoe? Set up as a kayak but named a Kanoe Latvija.
Anyway, while I was learning to kayak everybody would tell me lean one way the boat will go the other, and it does, if you lean it over to the deck seam. If you just lean it moderately, it turns toward the heeled side.
Canoe or kayak, it is a weird boat.
~~Chip
Thanks for the explanations
There’s so much I don’t know. It is always fun learning.
~~Chip