FDC-couch

today

8:30 a.m. Audubon Society Field Trip See Event Description

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9 a.m. Arcata Farmers' Market Arcata Plaza

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9:30 a.m. Discovery Walk: Unknown Waterfront See Event Description

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9:30 a.m. Manila Dunes Restoration Manila Community Center

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10 a.m. Manila Dunes Guided Walk Manila Community Center

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10 a.m. Library Book Sale Humboldt County Library

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10 a.m. Dia de los Muertos and Mexican Folk Art Sale Private Eureka home

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10 a.m. Final Arcata Farmer's Market Arcata Farmers' Market (off the plaza)

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11 a.m. Donlin Foreman Dance Workshop Dell'Arte

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2 p.m. Humboldt Coastal Nature Center Draft Trails Plan Walk Stamps House

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5 p.m. Bati Zado and Show Redwood Raks World Dance Studio

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6 p.m. The Tumbleweeds Chapala Cafe

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6 p.m. Ali Chaudhary (jazz duo) Libation

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6:30 p.m. Not Evil, Just Wrong Humboldt Area Foundation

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7 p.m. Guitar Stan (country) Old Town Coffee & Chocolates

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8 p.m. Guitar Orchestra of Barcelona Arkley Center for the Performing Arts

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8 p.m. Stones in His Pockets Arcata Playhouse

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8 p.m. A Christmas Carol North Coast Repertory Theater

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8 p.m. Donna Landry Swing Dance Moose Lodge

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8 p.m. North Coast Wind Ensemble Fulkerson Recital Hall at HSU

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8:30 p.m. The Last Minute Men (international) Cafe Mokka

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9 p.m. Ian McFeron Band (folk rock) Six Rivers Brewery

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9 p.m. The Michael Paul Band WAVE @ blue lake casino

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9 p.m. The Generatorz (classic rock) Central Station Cocktail Lounge

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9 p.m. Taxi Bear River Casino

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9 p.m. VJ Itchie Fingaz Pearl Lounge

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9 p.m. Jack Ruby Presents + Blue Street + Acufunkture (DIY rock) Jambalaya

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9 p.m. 2nd Annual Scorpio Bash The Red Fox Tavern

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10 p.m. Music by DJ Sidelines

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10 p.m. DJ Icy Hot Aunty Mo's Lounge

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10 p.m. Jemimah Puddleduck (rock) Humboldt Brews

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10 p.m. White Manna + Midday Veil + The King Salmon Duo (rock) Jambalaya

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11 p.m. Radio Moscow (psychadelic blues) + Mosquito Bandito (one-man surf/garage) The Alibi Lounge and Restaurant

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previous columns

April 3, 2008

Ancient Mariners

Sailing is an ancient enterprise. Humans used the wind to ...

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March 27, 2008

Hunting Worms

I recently went big-game hunting in the bay for a ...

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March 20, 2008

Tsunami Terrors

Understanding the nature of tsunamis could save your life. They ...

read >
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  • The vector-sum of forces on sail and keel is balanced by the resistance of moving the boat through water. Diagram by Don Garlick. The vector-sum of forces on sail and keel is balanced by the resistance of moving the boat through water. Diagram by Don Garlick.
  • Speed is a function of the boat's angle to the wind. Diagram by Don Garlick. Speed is a function of the boat's angle to the wind. Diagram by Don Garlick.
  • The length of the yacht is important. Diagram by Don Garlick. The length of the yacht is important. Diagram by Don Garlick.
Sailing

Sailing

By Don Garlick

The physics of sailing is outlined in the first diagram, showing the equilibrium between forces. The vector-sum of forces on sail and keel is balanced by the resistance of moving the boat through water.

The speed of a typical 10-meter yacht in winds of 10 and 20 knots, as a function of its angle to the wind, is shown in the second diagram (1 knot = 1.15 mph and 1 mile = 1.6 km). As shown in the third diagram, the length of the yacht is important because the speed of the induced bow wave varies with the wave's length. It is difficult for a boat to exceed the speed of a wave whose wavelength is longer than the boat, because the boat is then attempting to climb up the wave. With sufficient power, however, a speed-boat can ride up upon its bow wave and effectively hydroplane.

Although the maximum speed of a typical yacht is less than the wind speed, high-tech catamaran yachts have reached speeds about twice that of the wind. A windsurfer narrowly beat the yachting record this year with a speed of 49 knots (56 mph). The land yacht record is 117 m.p.h. in 30 m.p.h. winds!

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