A First Look at the Stuff that Holds Us Up
By Farwell Forrest
As a group, we paddlers are oddly incurious about the stuff that holds us up. I know that I was. Until I moved into an unplumbed camp, that is. Then things changed. Although Tamia and I live on the margin of a reservoir, we have to haul in every drop of water that we drink, every drop that we use to wash our dishes and our bodiesevery drop of water, in short, that we use for any purpose except cleaning our clothes.
Once I took clean water for granted. Turn the tap and out it came. Nowadays, however, as I watch the level in our cistern fall hour by hour, I find that I'm thinking a lot more about water. No surprise there, really. It's remarkable stuff.
Just what makes water so special?
Let's start with the most obvious thing. Water's heavy. Two or three times a week, Tamia and I each lug two six-gallon plastic jerrycans of water in from the end of our road, down the steep concrete staircase that leads to our house, and finally into the kitchen, where our cistern stands. We're only carrying 12 gallons each, but our individual loads weigh more than 100 pounds. And it could be much worse. Between us, we use, on average, only a little more than 8 US gallons a day for drinking, cooking and washing. If we were a typical American couple, we'd need to make 60 trips a week with our jerrycans and haul nearly six tons of water down our staircase. Thank God we're not typical!
Most Americans don't have to haul drinking water to their homes, of course. And most paddlers don't realize how heavy water is until the first time they try to nurse a swamped boat into a shore eddy to bail it out. Their waterlogged boat, a lithe and lively craft only a minute ago, is now a sluggish and stubborn beast, hard to move, hard to turn, and perilously unstable. If the paddlers' braces aren't good, or if there's another set of big waves just ahead, a swamped boat is almost always a prelude to a swim.
But let's suppose that the paddlers finally make it into the eddy. There's still the problem of bailing. If their boat is an open canoe, the process is simple enough, but they'll know they've done a day's work when they're finished. Bailing out a swamped Old Town Tripper means shifting nearly a ton of water.
Even kayakers can't escape this drudgery forever. Olympic-class paddler or casual day-tripper, it makes no difference. If you spend enough time on the water, sooner or later you'll blow a roll or pop your spray skirt. When that day comes, don't just swim your boat into the shallows and then try to pick it up and dump it. A flooded kayak weighs a lot less than a swamped canoe, to be sure, but even if you can lift it up, you risk straining seams or doing other damage. Keep your boat in the water instead. First, tip it up on edge and let as much water run out of the cockpit as possible. Next, slowly turn it over, keeping the cockpit clear of the water until it's upside-down. (It's easier to do this if you have someone to help you.) Now it's safe to pick up the almost-empty boat and rock it back and forth to get rid of the last of its unwanted watery cargo.
There's more. Not only is water very heavy, but it's also almost incompressible. No matter how hard you try, you just can't squeeze a gallon of water into a smaller jug. As countless water-skiers, jet-ski jockeys, and high-divers can attest, hitting the surface of the water at speed can be almost as painful a hitting a brick wall. I've seen water-skiers stunned into momentary unconsciousness after a spill. You can't expect water to "give" on impact. You just have to allow it time to move out of your way.
That's why it's so much harder to paddle fast than to loaf alongand why the work you have to do increases faster than your speed. You can't compress the water you're passing through, so you have to shove it aside. Water's heavy, remember? It takes a lot of muscle to pick it up and move it out of your way. And once you've pushed the water aside you've got to put it somewhere while you move forward. That "somewhere" is your boat's bow wave. When you're really stroking, you'll notice that you're generating a big, white bow wave. Sailors say that a boat that's moving fast "has a bone in her teeth," and it's a hard image to improve on. The "bone" is a temporary pile of displaced water.
The faster you go, the more water you've got to move (and stack up in your bow wave) each and every second, and the harder you have to work. That's why canoes and kayaks can't go faster than a fixed speed limit, no matter how strong the paddler and how streamlined her boat. But this ultimate speed limit isn't universal. It's called a boat's "hull speed," and it's determined solely by the boat's waterline length. The longer your boat, the faster you can go before you hit the limit. How fast is that? Well, just take the square root of your boat's waterline length and multiply it by 1.34. The result is your maximum practical speed in knots, or nautical miles per hour. Multiply this by 1.15 and you'll have your speed in the same miles per hour you get from your car's speedometer. For a boat with a 10-foot waterline, that works out to a little less than 5 mph. Increase your waterline to 15 feet, though, and you up your top speed 20 percent, to 6 mph.
This is one reason why expedition boaters and informal racers like long boats. They not only look faster than their shorter cousinsthey are faster.
There are exceptions to this rule. The most important one has to do with the type of hull that a boat has. Most kayaks and canoes are "displacement" craft. They travel through the water, rather than on it. Boats designed to skim over the water's surfacehydrofoils, many power craft, even surf skishave to displace much less water. Since they do less heavy lifting, these "planing" boats are largely exempt from the speed limit that nature sets for displacement craft. Nor is this phenomenon always limited to boats designed to plane. As sea kayakers who find themselves rushing shoreward on the crest of a breaking wave sometimes discover, even deep displacement hulls can go airborne. It can be an exciting, if
OK. Water's heavy, and it's hard to push around. So water must be pretty tough stuff, right?
Unfortunately, no. It's not tough at all. Like a highly-trained and enormously strong power-lifter who's knocked out of competition by a head cold, water's surprisingly vulnerable. All life depends on clean water. Yet it's easy to get it so dirty that it's no good for anything, and once fouled it's very hard to clean it up. That's why two folks living on a reservoir in the northern Adirondack foothills are hauling water from a public tap two miles from their home. The water's there on our doorstep, all right, but, in the words of the old South Devon fishermen in Stephen Reynolds' Alongshore, "'Tisn't fit. 'Tisn't hardly fit."
But that's a story for another day.
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