Monday, March 30, 2009

Gertrude and Gennaro

Boy, am I having fun with this prolonged windswell or what?

Hookipa is shoulder to head high every day (better on the rising tide), the wind is blowing strong and even if the spot is still overcrowded with pros and photographers in the water, we all still get our share of waves.
"Fun size", I was telling a friend yesterday, "because at my poor skill level, I feel like I can go for the lip without risking to do too much damage"...
Right. One hour later I was on the rocks.
This is the fifth or sixth time this season that I visit the rocks. They're like good old friends for me. I named most of them and I talk to them while I get slammed onto them: "Hi Gertrude, howzit going? Hey Gennaro don't hurt me please. Eat my gear, but don't hurt me, ok?"
Guess what: they listen! I didn't get a single scratch this year. But yesterday I destroyed sail and boom...

The windswell is mean. It hits you relentlessly (thanks Jake for the word) every 8 seconds. There's no lulls, only continuous white water coming at you and pushing you deeper and deeper. And it looks so small from the beach...
Here's my explanation of why the windswell is so gnarly.

A wave of 16 seconds period can shoal on the reef up to three times its size (that happens at Jaws, for example). At Hookipa, I observed that the shoaling factor for such a wave is pretty much 2: a three feet wave can grow up to six feet.
An 8 seconds wave, instead, won't grow much at all on the reef. That's also why it's so hard to read the windswell waves: they don't start feeling the reef until... they're on the reef! So a three feet wave will stay pretty much the same size when it breaks on the reef... IF it breaks on the reef!

Everybody knows that a wave breaks when it meets a bottom that is shallow 1.3 times its height.
What, you didn't know that? Come on, all my surfing students know that!
In other words, a three feet wave will break on a four feet deep bottom. That actually depends on the period too, as we were saying before.

Ok, all this theory to tell you that the amount of energy of a windswell that reaches the rocks at high tide is impressive, because most of it doesn't get released on the reef, but keeps traveling towards the shore.
A confirmation of this is the fact that on high tide the shore break in summer time under a windswell episode is often gnarlier than in winter time with a three times as big long period NW swell...

This picture of the Hookipa shore break clearly illustrates that.

Geez, what do I have to do to get your attention...

Awwright, forecast.
I feel like I've been sailing every day for...ever and it doesn't look like it's going to change any time soon. Plus, on top of the windswell, tomorrow there will be a respectable WNW swell (6 feet, 16 seconds at the NW buoy at 6pm).
Now, that's a really good recipe to goo see my rocky friends again (the long period waves knock you down and the windswell ones nudge you to the rocks), hence I'll sail elsewhere. The wind is going to be cranking as usual, hence I'll sail late.
Sounds like a plan.
I usually don't like making plans, but when the plans are like this, I don't really mind having them...

Thanks to Ray for the first photo.
And thanks to Brian and Aaron for reminding me to link Dan's histerical video. Check it out, it's very well done.


Nice said...

Buon giorno GP!

You mention the 1.4 factor for a swell to break. I didn't know that. What other measures should bne worth knowing? The reason I ask is that I want to calculate the sizes we see at home and when we should expect them to break. Windswell only though.

Anonymous said...

what a shore break!

Alberto said...

Ciao Giampaolo,
sempre molto interessante quello che scaturisce dal tuo approccio ingegneristico alle passioni della vita!
Riguardo agli incontri ravvicinati con Gertrude e Gennaro... hai mai pensato ad un post per cercare di far evitare tali esperienze a chi è interessato a fare le prime uscite ad Hookipa??
Io ho buttato giù questo per alcuni amici:
La tua esperienza è ovviamente maggiore e puoi apportare sicuramente consigli ulteriori.
Se ti piacciono gli schemini e le foto scrivimi alla mia mail che te le faccio usare.
Alberto B.

cammar said...

Hi Niclas,
period, direction and size of the swell are the most important factors. Forget about calculating. Take note of the of the different windswell episodes characteristics (I hope you guys have internet accessible buoys over there) and of the resulting wave size. I won't take long before you have a clear idea of what direction, size and period make for a good session.
Without buoys my life would be horrible...
BTW, this is a good book.

Anon, impressive uh?

Alberto, that is a fine piece of work you did.
It's so good that I translated it with google. Here's a not 100% accurate (but better than nothing) english translation
The only thing I slightly disagree is where to swim when in front of the rocks. Instead of straight out towards the ocean, as you say, I think it's better to swim towards out AND downwind with the current. Around 300 degrees, in case you have a compass with you ;)
Also, the best part of gear to grab to swim is the back footstrap. In the end, luck plays a big role too. If the gear is in the wrong way sometimes there's nothing you can do...

Nice said...

Nope, no buoys at all..

Dave said...

Dan's video is great. Jonesing to sail is an addiction!!!

Andreas Choulet said...

Aloha Italyboy!

Nice blog, I always follow it, it's fun to see what's going on Maui.
I've got a comment on your footstraps, I've using Core contour since 5 years, I love them!

In the last pic, it looks like you should open them up one step and move them closer thogheter, I might be wrong thoug.

Surf on!

ps If you ever want to see surf in the cold - ds.

jan said...

I looked at the photolink and found that sail of polakow.
It is by far the most harmonic sail shape I have seen for a while.

HSM is nice too but as always not so clean as np.

Greets Jan

mystery bob said...

Monday: N.O.A.A. (at the airport) 12:00 ENE 30, 1:00 NE 23, 2:00 ENE 28, 3:00 NE 29, 4:00 ENE 28
Now my arms reach the floor.

Lano said...

Nice shore break!

great vid as well GO, is that a relation of yours?

cammar said...

Sorry for the late reply here, thanks everyone.

Just one comment for Jan: the new NPs look terrific (just like every year's NP), but the look in the sail is not everything. I actually touched one yesterday (not sure about the exact model): so much monofilm, so stiff, felt like a slalom sail to me... I got different tastes!