Monday 18 February 2013

Running on the Sea

Here's an article I posted in the NSW Sea Kayaker's club magazine last year, reproduced with their permission.

Running on the Sea

Finding the Sweet Spot

I have spent a lot of time over the past couple of years trying to unlock the mystery of the ‘sweet spot’ of any particular kayak hull. This is the notion that by tuning in to your particular kayak’s hull shape & performance, you can maximise your forward speed and efficiency, expending minimal effort in doing so. It’s essentially to do with a slightly contorted idea of glide, or the amount of rest you can take between each stroke without detriment to your overall speed.

I had the concept demonstrated to me in no uncertain terms by a paddling mate & coach Rob ‘Max’ Walker, on a ski training paddle where we were trying to ride the stern wake of the Bundeena Ferry. Max had challenged me to hold onto the fast travelling wake as long as I could, no mean feat considering it hums along at about 12.5kmh. Hauling myself onto the second of the three waves that the wake produces I managed to hold position with a little more effort than normal, and Max then dared me to hop forward onto the steepest first wave.

I put my head down and paddled for all I was worth, thrashing around, water splashing everywhere like a Kingfish being hauled onto a tinny, dragging my bow closer & closer to the elusive sweet spot when the momentum of the moving water would once again propel me forward without such an effort.  In the brouhaha I heard Max’s evil laugh, and glanced across through the sweat pouring into my eyes to see him cruise over the lip at half my cadence & output level. ‘You’re hacking’ he barked at me, ‘let the hull do the work’. I eased off, tried to time my catch & effort rather than rating through the roof , and sure enough I slipped over the crest & joined him on the front wave with half the effort I’d been spluttering out moments earlier.

It was a short & salient lesson, and one that I took with me on a number of recent long days on the open sea. My motivation for developing the skill was self-preservation, trying to spare myself undue physical trauma in undertaking a number of demanding days of open ocean paddling ranging from 60km up to 117km. The idea that I could pull off a day of those proportions & back up well enough to do it again the next day was appealing for a number of reasons, least of all my own safety & the safety of my paddling mates.

Ostensibly it’s a piece of wizardry you can harness in following conditions, where the sea presents you with an opportunity to make ground at speed. Surfing waves on the ocean is to me the greatest joy in our sport, but not everyone can do it.

Why? Simply, I think as sea kayakers we’re not particularly tuned in to the idea of running with a sea. Paddlers who make ground effortlessly in following seas seem to be hardly paddling, just a faster, stronger stroke every now & then to keep the boat running. The rest of us tend to stop & start, getting a push from astern as a wave steepens, but then falling off the back as we either instinctively defend against anything potentially unpredictable like a broach, or lack the instinct or fitness to get our sea kayaks running.

We tend make my mistake of lifting our cadence or rating, and in the maelstrom of thrashing about, stall the momentum of the stroke, and then go again, over & over on a day’s paddling. Everyone who has paddled in a following sea & quickly exhausted themselves & reads this should know exactly what I mean!

To figure out how & when your own boat is inclined to run, I’d give one simple guide.

Head out onto your local waterway, preferably on a day when there is a breeze from behind generating enough of a sea to propel you along once you can hook into the flow. If you have a GPS, stick it on the front deck and watch your boat speed as you chase the crests of the waves in front of you. As soon as you feel yourself starting to exceed a comfortable cadence or effort level, back off and try to keep your speed up by timing everything a little better. Essentially, try to go just as fast by taking fewer paddle strokes.

My way of achieving this little bit of paddling nirvana is to visualise the crest of the wave in front of my bow pulling me along, and then adjusting power & cadence to make sure it stays there. If you drop off the back, remember there will be another wave along any second, but you’ll use energy chasing it down & starting again.

When you’re doing it right, you’ll find after a while that you can bring your effort level (measured properly if you have a GPS with a heart rate monitor) way down and not lose much at all in boat speed. When these measurable components start to line up; same speed, less effort, you will be some way towards working out how & where your hull begins to glide. Another little factor should also reveal itself if you’re paying attention, the point at which trying to go faster is a waste of time & effort.

In a perfect world we’d always paddle down sea, so what value is this idea of run in less favourable or even head-sea conditions? Again, to put it simply, it gives you a way to work out the point of diminishing returns, and therefore avoid reaching that extra watt of power that starts to fatigue you, but doesn’t actually add anything to your boat speed.

Not all boats run the same, but they all do it to some extent. As an exercise in developing a higher level of paddling efficiency it’s well worth working out where this sweet spot lurks on your kayak.

Postscript - here's a video of me running a nice little wind driven sea in my ski. The first minute is a reasonable example of what I'm describing above, trying to use the moving water to propel myself along, without using too much effort.

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