hearts and minds

November 8, 2006

Paddlesports Quick Physics – by Clyde Winter

Filed under: Paddlesports,Recreation — Hearts & Minds @ 11:00 am

A series of short articles discussing helpful technical concepts and dispelling common misconceptions. They’re applicable to whatever and wherever you’re paddling, and intended to increase your fun and proficiency.

In sorrow for and memory of those watersheds that have been and are being violated …
In gratitude to those who are helping us leave a cleaner wake …
In hopes that we will learn and act before it’s too late …
These notes are for all who love and respect the water.

The articles in this series are written, published, and copyright by Clyde Winter, canoeist, kayaker, and U.S. merchant mariner (Master and Chief Engineer of inspected motor vessels up to 1600 gross tons on any waters).

The Table of Contents that follows has direct hyperlinks to each article.
Click on the chapter title, and the article will appear in front of you.
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August 6, 2006

I. The Peripatetic Pivot Point – by clyde winter

Filed under: Paddlesports — Hearts & Minds @ 1:43 pm

A force applied to a free-floating boat tends to change the linear (that means straight line) velocity (that means speed and/or direction) of the boat.  And such a force also usually tends to change the angular momentum of the boat (that means rotation of the boat around a pivot point).  In this article we are focusing on that pivot point.  Knowing where a boat’s pivot point is at any given moment helps to dispel much of the mystery and prevent the disconcerting or unpleasant surprises inherent in self-directed boat travel.  The tricky thing about the pivot point is that the location of the pivot point changes from moment to moment because the location of the pivot point of a boat that is underway depends on how or even whether the boat is already moving relative to the water that it is in contact with at that moment. (more…)

II. Momentum and Energy – by clyde winter

Filed under: Paddlesports — Hearts & Minds @ 1:42 pm

Use it or lose it, prn. (Ask your nurse what prn means, bunky, and thank him or her for their service.)

Momentum used well helps you to eddy hop upstream, punch out through surf, catch waves, cross eddy lines and boof drops. Out of control momentum can cause you to miss that very last takeout or scouting eddy, wrap a bridge abutment, snag a log jam, or broach and capsize while surfing. Momentum can make life easy and save you trouble, but it can get you into trouble too. Kinetic energy imparts zest but it can also mess up your boat and your trip.
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III. Everything Floats – by clyde winter

Filed under: Paddlesports — Hearts & Minds @ 1:41 pm

Anything that you carry in your boat that remains less dense than water when immersed and that is secured properly is flotation. It can be air bags, gear bags, packs, boxes, or structural foam. It can be a load of firewood if properly lashed in place. It’s not flotation if it can float free, deflate, flood, or shift position. That stuff is called flotsam and lost outfit. You don’t need flotation if the boat doesn’t swamp or capsize. If it does, wherever you are and no matter what kind of water you’re in, the more flotation you have the better off you’ll be. In all cases it’ll make recovering the boat and gear easier and quicker. In some cases it could mean survival.
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IV. Buoyancy and Uprightness – by clyde winter

Filed under: Paddlesports — Hearts & Minds @ 1:40 pm

The cumulative weight of boat and everything in it, including you, can be considered as a force acting at a point called the center of gravity, directed vertically downward towards the center of the earth. If things move around inside the boat, the center of gravity also moves. If everything inside stays in the same place relative to the hull, then the center of gravity stays at the same point, regardless of whether the boat heels left or right, or stays on an even keel. You can control the center of gravity by keeping weight as low as feasible in the boat, and by keeping it from shifting and lurching about. The worst kind of weight to carry in your boat is anything that is free to uncontrollably shift or slosh around. It’s bad because when the boat heels to one side, this kind of weight moves, thus shifting the center of gravity to the low side. From the standpoint of stability and seaworthiness, the best way to carry your outfit is as secured ballast that doubles as secured flotation.
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V. Kayak Capsize Recovery and Survival – by clyde winter

Filed under: Paddlesports,Recreation — Hearts & Minds @ 1:39 pm

Twenty five years ago this spring I was preparing for a solo sea kayak voyage that departed from the Fraser River (near the border of British Columbia and Washington State) and over four months later arrived 1200 miles north, at the mouth of the Chilkat River near Haines, Alaska. It was a truly wonderful, beautiful, gratifying experience. Ralph Frese, canoe builder/blacksmith, and friends I met in the Vancouver area (Steve Schleicher, kayak designer, and Joe Matuska, paddle builder) helped with very valuable resources and advice before departure. I think every bit of their help proved to be sound and credible. And I’m going to pass an important part of that help on to you in this article. (more…)

The Appearance of A Rock

Filed under: Environment,Paddlesports,Recreation — Hearts & Minds @ 1:39 pm

We drifted around the corner into a quiet swamp, looking at and listening to this new neighborhood we were invading. My attention was drawn to a large wetted rock protruding slightly above the water’s surface. It didn’t quite fit with the surroundings. Everything else was water in near flood stage, the expansive swamp all around, and luxurious wetland vegetation. Not another inorganic solid was in sight.

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