Wild wind & water work
It’s a rare and exhilarating experience to lie at anchor with steady 35 knot winds howling through the rigging. Gato Verde is galloping on her anchor bridle tonight. Each gust makes the whole boat shudder. Last night the aerial soundscape was geese honking, great blue herons squawking, and tiny fish leaping. Tonight it is all elemental: moaning and whistling of wind over wire, lapping waves, rattling ports, and the creaking of a thousand stowed items jostled by the boats vibrations.
Today was a windy day, with the orcas lingering in the Strait of Juan de Fuca — just beyond our listening range. We made an effort to be at the right place at the right time, but didn’t get lucky like yesterday. Instead, we had a lot of good sailing and even managed to generate some electricity by using the props to slow ourselves down as we ran with the wind.
Alex holds the record for generating a peak current of 10.6 amps at 52 volts on a single motor! That’s a peak power generation of about 500 watts. I was thinking about how to put that in perspective this evening at anchor. Normally, I say use incandescent light bulbs (100W say) or toasters (1kW) and hair dryers (2kW) as references.
But I want to make an intuitive, tangible connection between food (which powers us) and green power on the Gato Verde, like wind/water power. Luckily, as Anne prepared ocean algae pudding (wonderfully accurate texture), Ash mentioned that sugar has an energy density of 16.5 kJ/g. My Treo informs me that chocolate packs 18.5 MJ/kg, while biodiesel offers 41.2 MJ/kg.
Since a watt is just a rate of energy flow equivalent to joules/second, Alex was generating 500 J/s. To get an equivalent supply rate of energy, you could eat 2.7 g of chocolate in 100 seconds, or burn 1.2 g of biodiesel in 100 seconds.
I also like to mention Greg Lemond on a hill climb in the Tour du France as one of the few humans who can generate 700W for extended periods. At rest, humans need about 100W to keep warm and happy. That range is confirmed by the NOLS Cookery book on board that says easy going sailors in warm climates should eat 2500 kcal per day and active, cold weather sailors should eat more like 5000 kcal (5000 “food” Calories). Averaged over 24 hours (86,400 seconds) and knowing there are 3.8 J/calorie, the NOLS rations are meant to supply 110 – 220 watts. This implies that it would take 2-4 of us well-fed humans pulling pretty hard to match the power of the wind.
Twitter
LinkedIn
Facebook