Mechanics of Side Slip

-- Last Updated: Jul-30-15 11:29 PM EST --

I've been studying Roger Schumann's video of the side slip (stationary/running draw) and know what the steps are to initiate the stroke, but I don't understand the mechanics.

His arms are quiet and I don't see any manipulation of the blade, so what is making his kayak move sideways while still traveling forward?

Also, when they say "establish hull speed," how fast is "hull speed"?

As always, my thanks.

Slip

– Last Updated: Jul-31-15 6:42 AM EST –

You need some speed for it to work, just like you need some speed for a rudder to work. Place the blade in the water parallel to the boat beside you and twist the leading edge away from the boat. You will find the balance point after a few tries.

You can do the same thing up near the bow and it's called a bow rudder.

They are very handy stokes when in tight places such as mangrove tunnels when it is difficult to take a stoke even with a broken down paddle.

Grayhawk got this started…

– Last Updated: Jul-31-15 1:07 AM EST –

... but since visualizing how this works doesn't come naturally to you, I'll try to walk you through it some. You'll see it a lot more clearly when you try it on the water.

Yes, your boat needs to already be moving forward as you do this. If you plant the paddle blade alongside the hull when you are coasting along at a good clip, with the flat of the blade parallel to the alignment of the boat, what happens? Nothing happens. The blade just cuts through the water like a knife. But if you turn the blade at an angle so the leading edge is farther from the boat than the trailing edge (remember that the blade is moving through the water at the same speed as the boat), what happens then? In that case, the paddle "wants" to take off in that new direction, because cutting through the water like a knife is what it does most easily, and the direction of slicing is angled away from you now. Of course, the paddle can't take off on its own because you are holding it and won't let it go, so instead, it starts acting like a wedge, pulling on your arms and asking you to come along. And that pulling force pulls you, and your whole boat. But it only works for as long as your boat is traveling forward, which is why the movement is diagonal - a combination of forward movement adjusted by a pulling force that is applied directly sideways. Once the boat stops, the paddle stops too, and it can't generate that pulling force if it's stationary in the water.

As Grayhawk mentioned, there's a balance point where the sideways force generated by the paddle pulls the whole boat sideways without changing the direction that it is pointed. Move the paddle more to the rear and it pulls the stern sideways. Move it more toward the bow and it pulls the bow sideways. You need to find the "sweet spot" where neither the bow nor the stern take the lead in moving sideways. Look up Marc Ornstein's thread on free-style canoeing (it was a few months ago) if you want a way to visualize where that sweet spot is for any particular blade angle that you choose (kayak, canoe, it doesn't matter), but trial and error works too.

Oh, if the guy in the video used the term "hull speed", that's unfortunate, because he is using a term with established meaning for something completely different. What he really means is that you need to get your boat going at a reasonable speed for the side-slip to work. That's all. "Hull speed" actually describes a particular speed where the boat gets more or less "trapped" between the waves that it makes as it travels, so going faster becomes difficult, often so much more difficult that "hull speed" is as fast at the boat will go (you've probably noticed that you can't increase your speed without limit. The principle behind "hull speed" is why you can "only go so fast". There's no need to get into the details behind that right now).

Torso again
Rotation, that is.



I remember learning moving draw first with wrist movement but later switched to torso rotation instead. Try it both ways. I have no idea how Roger Schumann does it.

scull
with blade vertical, possibly held shafts out blade in on a half stroke of the figure 8 motion.



In SEA KAYAKER.



Hull speed is speed your hull works at with this stroke.

static draw
The maneuver shown in the video is a side slip. The stroke used to execute the maneuver is a static (or hanging) draw. This is not the same as an active lateral draw or a sculling draw, which some posters seem to be talking about.



As Eric described, the maneuver only works so long as the boat is moving faster than the water. The angulation of the paddle blade face to the water through which it is moving creates a vector force which moves the boat laterally as it continues forward. The lateral motion only continues while the boat is moving faster than the water.



When starting out it is best to place the paddle in the water directly aligned with the keel line and then angle the blade very conservatively at first. If you use too great an angle right away you will find the stroke difficult to control and may completely stall the boat. As time goes on and you locate the sweet spot, you can use a less conservative angle.



You can also do side slips using a static pry, although there is usually not much reason to do so with a double bladed paddle. For the static draw, the power face of the paddle is loaded (i.e, the moving water is striking the power face). For the static pry the back face of the blade is loaded. For the static draw the leading edge of the paddle is angled away from the hull. For the static pry the leading edge is angled towards the hull. The pry is usually harder to control. Remember that with the static pry and static draw, the lateral motion of the boat will be the direction toward which the leading edge of the paddle blade is angled.



A tandem canoe team with their paddles on opposite sides of the boat can execute a very nice side slip when one partner uses a static draw and the other a static pry.



One point not mentioned or shown in the video is that the effectiveness of side slips and abeam maneuvers is increased somewhat by “elevating the side of opposition” or heeling the boat slightly away from the side you want to slip to. This allows water to flow somewhat more smoothly under the hull as it slips.

I’ll only add 1 tip

– Last Updated: Jul-31-15 8:29 AM EST –

since the descriptions given here are very good already. But you have to make sure when you plant and angle the blade that your whole body is engaged, otherwise the water will simply pull your blade away from the boat. You want to keep that onside elbow close to your torso and lock it in keeping everything tight thru the thigh pads. I notice that when I sideslip I'm engaging the thigh or knee pads and particularly the onside one, probably heeling the boat a bit as pblanc suggests.

OK two things. You might play with the fore/aft position of the blade as well. I also second the comment regarding torso rotation (3).

On windy days, with shifting winds

– Last Updated: Jul-31-15 9:07 AM EST –

..try to avoid letting your paddle strokes slide into a sweep(moreso canoe). You're essentially "draw"-ing while the hull is either stationary or moving forward..the main issue is to move the whole hull over to one side when the hull already has sufficient forward momentum. If you don't get the amount of hull tilt-angle right it'll just create more resistance with the water and the slippage will die on you... You're consistently "draw"-ing the whole hull's midships without falling into a sweep, of any direction. More important with a canoe, but still of use when there isn't a whole lot of room for your kayak's bow to slide into.

Works for both moving and static draws
Torso rotation. Should have written that instead of what I did in the first post. I’ve heard it referred to as facing your work.

Gratitude
Thanks so much for the feedback. You’ve helped me understand why the boat moves sideways. I really need to keep Issac Newton in mind when I think about these things.



Yes, I first saw this stroke demonstrated in the freestyle canoe thread. It was beautifully done. I never connected it to a kayak until it showed up when I was looking for edging info on the bow rudder.



And yes, it’s definitely not a sculling draw. I’m fairly competent with that stroke.



Hull speed: That’s the first instruction for each of the four maneuvers shown in the videos. The advice to get the boat moving faster than the water makes a lot more sense.



Blade angulation: the upper hand position looks the same as for the bow rudder. How far out should the blade be planted for the hanging draw? One UK site recommends 23-inches. Full torso rotation will place both hands over the water, but how far out?



You’re very good teachers with clear and concise explanations. Thank you for sharing your expertise. I appreciate the help.



Will see how it goes this evening.




hand out of car window
I suspect the good descriptions people have given have clarified for you, but if not - here is an easy way to think of it. I am sure as kids(and even some of us who are not officially kids but are kids at heart), you stuck your hand out of a moving car’s window and felt the lift and downward pull as you changed your hand’s angle to the wind? This is what the static draw is doing. You are using the movement through the water and angle of the blade to pull your boat (can also be done to push your boat, but that is less common).

vertical paddle shaft

– Last Updated: Jul-31-15 1:26 PM EST –

The "hanging draw" side slip would actually work optimally if you could somehow have the paddle blade completely vertical and situated directly under the center of the boat along the keel line.

With the paddle shaft and blade absolutely vertical to the horizon, the vector of force that effects the side slip will be directed perfectly laterally with no lifting force on the blade.

I would keep the blade close to the side of the hull to allow as vertical a paddle shaft as is comfortably possible. This allows you to keep your lower elbow tucked in for stability and allows a more comfortable reach for your top hand to keep your hands "stacked".

I steer my car with my hand out the
window.

I still do that, Peter,
(on the back roads) but my arms aren’t as long as Yanoer’s so I have to steer with my right hand.



Thank you, pblanc. It’s a lovely day here, the sky is clear, there’ll be a full moon tonight and we still have daylight until 9:30 pm. I’ll have plenty of time to experiment and play.


Couple of other points to consider
as you play with the side slip.



It is generally necessary to adjust both the blade angle and the blade position along the long axis of the boat during the execution.



If your boat has a lot of forward speed (relative to the water) then you can get a fair amount of lateral movement with a fairly closed (conservative) blade angle. As the boat momentum slows, you may need to open the power face to the water more (increase the blade angle) to keep the lateral movement going. Opening up the angle will create more drag on the paddle and slow the forward momentum of the boat, however.



Ideally to get a pure lateral movement without any yaw (turning) you want to have the blade positioned right astride the center of buoyancy of the hull. But the center of buoyancy of the hull can change with the speed of the hull, so you may need to move the blade forward or back some to keep the boat from turning.



In my experience, I have generally found it necessary to move the paddle blade forward some as the boat slows to keep it from turning, but I have heard others say the exact opposite. It might depend on the hull design. My thought is that many hulls squat down somewhat at the stern while under speed, but then level out as they slow, so that the center of buoyancy moves forward a bit.

Have printed
the tips and instructions from this thread and they’ll be bagged and carried on my deck tonight. Just in case I need them.



Thanks.


my mechanic taught me that
He said he could fix my alignment for cheap.

I’ve seen your car, Yanoer

– Last Updated: Jul-31-15 6:24 PM EST –

I don't doubt that it needs manual assist to steer.

;)

pull
with thighs, butt on the power stroke

That sweet spot sure was sweet
when I hit it. Purely by accident. It was such a neat sensation and visual to be traveling sideways and forward!



My subsequent attempts weren’t so successful so I paddled until the wind died down then tried again. Pulled off another good one (to starboard this time), one complete stall, and the balance of my attempts got the boat going sideways, but not tracking straight. I need a lot of fine tuning, but I’ll get there.



Getting very comfortable holding the paddle vertically did help in one way: I pulled off the best bow rudders I’ve ever done. That was so much fun, I just did bow rudders for the last mile back to my shore.



Thanks for all the coaching that led to such a great evening. Tomorrow I’ll have most of the day to play.