stayin' high on da wave

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3 weeks 3 days ago #40166 by LaPerouseBay

La Perouse Bay that section at Maliko looks familiar in places to one of the (many) hurdles I’m working to overcome. It looks to me like you have at least two trains of swell running in similar directions. In a few places (eg early on around 0:17) you appear to have great positioning, high but definitely at the front edge of a swell peak, when the peak stretches into a plateau and suddenly you are behind a hump. Like your dromedary has sneakily turned into a camel as the faster train passes the slower.
It is at this very moment that hard won momentum can be lost. The two options seem to be to sprint hard at the “plateau” phase of this cycle and stay ahead of the faster peak, or turn diagonal as the faster one passes under to avoid paddling dead uphill. Then spin straight as you did and accelerate onto the next wave. There is always a speed penalty though with this approach, with a jagged Garmin trace betraying the loss of glide.
As one of you mentioned this seems to happen more in light wind conditions where the difference between wind chop and ground swell speeds are too great for someone of my speed and weight to bridge without a lot of effort.
When I look at videos of myself in these “technical” conditions I lament all those runs apparently getting ahead of me. Just seems to me there’s no where to take your speed in this situation.

Yes, the feeling of nowhere to take your speed is common with me. That's why I did so much research in my early days, and continue to do so.

There are some weird things happening in that video due to the ocean depth.

Here's another video, earlier in the same run, deeper water. I tried to publish it before the first one, but YouTube bots pinged it for copyright on the music. (The music was legal, but I had to wait 30 days).



Here is the line, with start/finish pins on the videos. I've been watching my depth with Google Earth overlays for many years. One click on and off.




Zoomed in a bit. Some of Google Earth's satellite images are so sharp I've been able to pick out paddlers. Location of overlays is extremely accurate. I can double check stuff like buoys in the open ocean on that chart and it's just magic. You should be able to see the reef on this pic. I can see it under my boat in the UHD videos. That path was pulled right off the GoPro footage.





So, as for weirdness in the 12 foot water, it's because at 1/20th of the wavelength, those are "shallow water" waves. They pile up and steer around in seemingly random patterns. So, I relax and let the ocean carry me along. I keep watching and focusing on moving to my right, maybe grabbing a bit of left if it's a quick, safe gain. My main idea, always, is, 'where is that primary swell and how soon will it be back?'

100 foot water video is more groomed. (It's in just less than 1/2 the wavelength. It's just starting to 'feel' the bottom, that's an "intermediate" not a true 'deep water' swell, but very close). The converter below will show how the speeds change as the depth decreases).

The swells are about 8 seconds. So, the speed of them is right at 12.5 mph. Just like my speed graph. It all falls into place with a graph on the video.

Notice how the speed remains high as I'm falling off the back of the wave? That's accurate. It's how our little boats behave as faster swells move under us. The effect is very similar to what you see in this GIF of Stokes drift. See how the little red dot scoots along at the top of the wave? That's what we are doing too - and why it's so important to hold as much of that momentum as possible.

commons.wikimedia.org/wiki/File:Deep_water_wave.gif

If you have a buoy nearby, you can compute the speed of the swells in your conditions. You can plug your numbers into this converter. Ocean waves are crazy fast. We seldom see anything above 10 seconds at Maliko.

swellbeat.com/wave-calculator/

Here's some background on where all that stuff comes from.

www.stormsurf.com/page2/tutorials/wavebasics.shtml

downwind dilettante
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3 weeks 3 days ago #40167 by Dratz
Replied by Dratz on topic stayin' high on da wave
Great post LPB, so much to chew on!
I just recorded a vid at the enclosed Botany Bay in about 20-25knots of wind, which has several similarities to yours. Throughout, the trains of swell were moving at 13km/h. Early in the fetch they were pretty ordered, but later they stretched out and compressed as they interacted with other trains moving obliquely in one or another direction.
My trace for the first few km was a pretty even 13km/hr. Later on the dreaded and effortful peaks and troughs started to make an appearance on my speed trace.
If I sprinted over a flat section of “destructive interference” i could bounce over, or punch through, the smaller waves in front and obtain the illusion of jumping one main swell ahead. Most of the time though this would eventually lead to a slow down. As i looked at the vid it dawned on me that i was not “falling off the back of the wave” as much as running into the larger swell ahead that had been temporarily hidden but had now reappeared. My short term average of those sprints and the stalls always ended up being…. 13km/h.
In your vid, you get a burst of speed at around 0:50 and push over a flat section. Your speed gets up to 13mph. It looks like you “fall off the back” then at around 1:07 and the speed drops temporarily to around 7mph. I wonder in fact this was just your original trough reforming, with you now at the front of the trough rather than back up and high on your original crest. To get through that pesky reforming wave ahead probably required you to double up your first sprint with another.

The stuff on bathymetry is fascinating. Thanks for sharing.

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3 weeks 3 days ago #40168 by LaPerouseBay

In your vid, you get a burst of speed at around 0:50 and push over a flat section. Your speed gets up to 13mph. It looks like you “fall off the back” then at around 1:07 and the speed drops temporarily to around 7mph. I wonder in fact this was just your original trough reforming, with you now at the front of the trough rather than back up and high on your original crest. To get through that pesky reforming wave ahead probably required you to double up your first sprint with another.

Yes, I think it would have taken a big effort to stay up with that swell.

Judging by how quickly the next one rolled thru and gave me a nice glide, I think my strategy to look for smaller, crossing bumps going right was a good one.
I typically concentrate on going right and not taking any low hanging fruit dive bombing lefts. With that mindset, you can easily see in that video what I was focusing on. All that pausing was me waiting for the crossing swells to line up. That's the only way I can get on waves that fast.

Fun day. That path right along the 20 fathom line has always been my fastest.

downwind dilettante
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3 weeks 3 days ago #40169 by Dratz
Replied by Dratz on topic stayin' high on da wave
Here’s the link to the BB vid from a few days ago:



(Play some nice Chopin or something for a BYO soundtrack….)

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3 weeks 2 days ago #40171 by LaPerouseBay
Very nice downwinding there. I agree that you were keeping up with everything. It's easy to see how you were in full control.

That slight spin to the right is not an error in my book. It's an indication that you were right up in front of those waves, trying to advance. Sometimes that little spin out happens, but often only takes a moment to get going again - because you have advanced up in front of something at a pace that just barely missed. Within moments you are back in the flow.

That looks like reverb or boat wake to me, and it's nice to see how you let the ski do it's magic. They appear to mow right thru it and stay up to speed. You can see the peaks of the more powerful wave you are on, they stay visible, at that constant speed you hold. I've always marveled at how skis can do that. We get it when we approach the entrance to the breakwall at the harbor after a maliko run. If I ignore all the slop and just keep paddling on the line that was working just before that crap shows up, the boat magically just keeps going. Very rewarding. I just remember to tell myself not to trust what I'm seeing, I'm not going to fall if I just imagine the line is clean and the slop won't spill me. Magic how skis do that.

Those Vega boats look very responsive. Kai is a living legend around here. He's quite the talent at shaping downwind boats.

downwind dilettante

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3 weeks 7 hours ago #40172 by mrcharly
Replied by mrcharly on topic stayin' high on da wave

If you have a buoy nearby, you can compute the speed of the swells in your conditions. You can plug your numbers into this converter. Ocean waves are crazy fast. We seldom see anything above 10 seconds at Maliko.
swellbeat.com/wave-calculator/

Thanks for that.

I plugged the numbers in for the swell currently running offshore.

24kph - increasing to 34 in some areas.

It gets crazy rough, even when the swell isn't large. only a 2m swell with a 5s period. The swell and waves are really steep.

I don't know how people catch bumps in those conditions. This morning I just stayed in the loch, which beat me up, what with the reflections off islands.

Mostly I paddle in this area; goo.gl/maps/R7sWpqBRBSNFUkcL9

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2 weeks 6 days ago - 2 weeks 6 days ago #40173 by LaPerouseBay
^Wow, that's the same latitude as the southern tip of Alaska.
I copy pasted the coordinates of your Google pin into Windy.com.
They use the European Centre for Medium-Range Weather Forecasts (ECMWF) model.
www.windy.com/58.117/-6.394/waves?waves,...6,38.438,3,m:fh0afYv
This video is from your neighborhood. That's the Windy.com site back then, it's improved a lot lately.
He updated that voyage with additional footage, it's on his channel.

downwind dilettante
Last edit: 2 weeks 6 days ago by LaPerouseBay.

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2 weeks 6 days ago #40174 by mrcharly
Replied by mrcharly on topic stayin' high on da wave
I don't go out to sea in storm force 10!
I have paddled on the loch when it was blowing a force 9 - the wind was from the west, so no sea swell rolling in. It was hilarious. Absolutely exhausted myself paddling 1km; took about 30min. Then a few min back to the launch point at warp factor 10.

A lot warmer here than Alaska, but windier as well. Currently gusting up to 55-60knots.

It is a great location for general sea paddling, there are many km of sea lochs, then the coastline to explore. Maybe I'll get enough fitness back to manage some trips to the offshore islands

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2 weeks 4 days ago #40175 by Dratz
Replied by Dratz on topic stayin' high on da wave
LPB,
Watching your video again I was struck by the meandering, constant motion of the Bach partita. I am certain you did not choose Bach randomly. This partita at once is never the same but also presages the hypnotic minimalism of Phillip Glass and others two centuries later. Bach’s music was not only beautiful but incredibly structured along mathematical lines, and to me bears a striking resemblance to the complexity of swell trains and patterns that we experience on a downwind. A perfect match.

If you are interested, here’s a nice bit of graphical transformation of Bach music:

www.openculture.com/2013/02/the_genius_o..._a_mobius_strip.html

For a deeper geek-peek at Bach and maths check out this video. The fugue might as well be an ocean buoy data set!



And my favourite simply for its haunting beauty:

www.thepiano.sg/piano/read/harmonised-vi...achs-prelude-c-major

Thanks for reminding me of this!

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2 weeks 2 days ago #40179 by LaPerouseBay
I'm just beginning to go down the rabbit hole of J.S. on smalin's channel. I'm not a musician but I love classical music. Gotta love youtube for all it's depth and free entertainment on such a rewarding subject. I've been watching Rousseau for a few years.



Here's a video of the reverb I was referring to earlier.



I'm trying to go left, main energy is going to my right. So I sneak in behind them as they go under and try to extend as far as possible, surfing left. As I get closer, the reverb starts. Odd moguls start to pop up. I use the same timing that worked earlier to surf left. When those odd moguls become a distraction, I close my eyes and keep paddling. The boat knows where to go. Same with adding music. I find something J.S. wrote, note the length and chop out some video the same length. If anything lines up it's all him, not my editing.

downwind dilettante

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2 weeks 2 days ago #40180 by mrcharly
Replied by mrcharly on topic stayin' high on da wave
Very odd conditions the other day. About 10knots of wind, my 'home' loch was so calm I thought about taking my race K1 out.

Crossed over into the next loch and it was totally different. The further I went out, the rougher it got. Not big wave, just a metre or so, but very steep and hard work to paddle into them (ski smashing down into the troughs). Guess it was partly due to the outgoing tide steepening the swell.

So, on the return, I worked hard on catching some of the steep little waves. A couple of times I 'got it'.

First thing; normally, when the bow starts to bury (I'm in the trough), I start to put an effort in to get speed up. I tried leaving it until later, when the 'elevator' feeling came in as the wave lifted the boat. Much easier, and less exhausting.

Second, I tried to stay much higher up the waves. Twice, I managed to make this work, and link multiple waves. What an express ride when I did!

I really need to work on my skills.

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