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don’t get bit

csabi

Part two of Kevin Hall’s intense focus on downwind sailing. Part one can be found here.

You may have experienced a team trying to obey the targets, and gotten the feeling in your gut that all those goddamn numbers are worse than a dead battery. You were probably right! The question is why? And now what?

We want to learn to use the instruments downwind as helpful inputs. Spoiler alert! This takes time. When everything is going great, we are able to get to our Tgt BSP with just a little heat, and then we are able to stay as deep as our Tgt TWA without the speed dropping. The call “up 2” comes as the kite sheet goes ever-so-slightly soft, and the speed comes back. The call “good pressure” comes and a modest attempt to grab some depth is made. These tiny, almost imperceptible corrections and responses to lulls or puffs produce average data right on the target line. Simple.

Now suppose we are doing that already and another boat which we should be able to hold off continues to outperform us. If it’s light wind, chances are they are doing it by somehow sailing deeper without loosing too much speed. If it’s windier, chances are they are somehow sailing faster without losing too much depth. If we had a coach’s video of both boats, my bet is the better performing boat would show a more constant angle of heel.

The slower boat probably has this happening onboard: the boatspeed is less than the “Tgt BSP”, so the helmsman heats it up a bit. So far so good. The speed doesn’t come very quickly, so more heat is added. Now we are sailing considerably higher (narrower) than target TWA, and the heel is shooting past target heel, so the drag is increasing. We notice how narrow we are and the speed finally comes, so we start taking it back down.

We have a pretty good head of apparent steam built up now, and with our target TWA in mind, we burn it off to that nice angle, maybe even one or two degrees deeper. The heel reduces as the apparent wind speed dissipates, and the BSP starts to crash. We try heating a little less this time, but the speed doesn’t come very quickly (which could be not enough crew weight, or too much crew weight and an over-trimmed kite!) and so we start the cycle over. If this happens for more than a few cycles, you might hear some of the crew mumble that they wish the displays spontaneously stopped working.

Some teams use displayed AWA, which can help smooth out this roller coaster a little because as AWS drops, the AWA starts creeping aft and a display of AWA with values which are increasing tells that story pretty well. A top helmswoman is basically sailing by the combo of apparent wind angle and heel that she feels. But doing it with a display is still all very left-brain and algorithmic: remember, digital numbers changing do a very poor job of conveying rate of change information.

This is why most helms like the hundredths of a knot on the boatspeed display. It’s not because they can actually helm to within a couple hundredths. It’s because the rate of “scrolling” of the hundredths digits provides the feel of early warning which doesn’t come from the tenths. And top helmspeople may not prefer a “better/more accurate” damping algorithm for the same reason: it changes the feel they have accrued from thousands of hours of helming.

Let’s try to figure out why that dead battery might just be better for many teams, but the top teams still use instruments. On the struggling team, the instruments are given too much authority, and they’re distracting attention from that which matters most. Instead of being used as one of many “picture painting inputs” or “feel generators”, the instruments are seen as the most accurate and most important information. They seem to carry the weight of the Western Worldview behind them: science says the answer is X & Y, the display says I need to increase x to get to X and decrease y to get to Y, the vector inputs required to make that happen are produced by input Z, etc etc.

Not only that, but all that sacred data is always a little 2000-and-late because of damping! Meanwhile, a boat with a dead battery sails past with the crew weight and kite sheet cycling around a narrow, refined-through-experience average as a subtle, choreographed ballet.

On teams that have been together for a while, the crew moves as one, and uses the interplay of the targets and the tactician’s calls to help the helm and trimmer find and keep the best mode. The numbers on the displays are like a little cartoon, and the couple sailors who interpret them poorly and move against the grain gradually learn from the group to see the same picture. Next time that show is on, they know how to move.

On top teams, all this is happening at a very flow level and is almost invisible: everyone agrees about the story that the mast cartoon is telling. When the mode is slightly deeper and too-much slower than targets (AND the performance relative to other boats is suggesting that too!), weight is smoothly moved out a bit to encourage the helmsman to sail slightly hotter to keep near target heel.

On the other hand, if we need to sail deeper to stay in a breeze or for tactical reasons, the crew weight leads the mode change: as the crew gently starts moving inboard, the helm feels this on the rudder or senses it in the heel or sees it on the horizon or bubble, and begins to bleed to a deeper mode. From off the boat we don’t see the heel change. We’re talking about perceiving and responding to hundredths of a degree of heel or two-finger pressure changes on the tiller, by feel.

Downwind targets, then, are still a bit of a static cross-section of a huge and rippling risk-reward surface. They reference a historical baseline which has nothing to say about whether there are even waves! If it’s light and flat water, assuming we are not just plain sailing too soft, it might be risky to heat too much but not accelerate enough. On the other hand, in uncharacteristically big waves and marginal surfing, it might be risky not to stay “way too hot for target” and keep missing waves that could yield a 100 yard surf. That shit ain’t up on the mast. It’s inside the most powerful databases onboard: the sailors who saw it work in conditions “much like today”.

There is another, perhaps better approach to this entire discussion. Downwind sailing done well on a keelboat is a lot like a tight band recording an epic album. Grab the documentary “Sound City” and listen to Neil Young talk about how they got the algorithm wrong when we went digital. Watch Dave Grohl making music. Listen to the ocean.

Photo thanks to Max Ranchi.

 

 

csabi

December 18th, 2017

http://www.camet.com/

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