Some of us have literally spent weeks worrying about low water. No sense worrying any more or complaining about it any longer because it sure looks like that’s what we’re going to get. The hoped for rain simply isn’t going to come in time for the race. The river is not just low; it’s dramatically and historically low. It’s lower than it was on race day two years ago, which itself was the lowest anyone could remember — and it’s lower than that by a lot.
Want numbers? The stream gauge at Six Mile Falls reports a depth of 3.8 feet and a flow of a 144 cubic feet per second. This time of year, the flow generally averages 1,000 cfs. Two years ago, the low year, when the Bangor Daily News headline following the race read “What a Slog,” the gauge read 4.4 feet and 300 cfs.
This year’s Kenduskeag Stream Canoe Race is sure to be unlike any other. And that is one reason to participate. Accept the low water. Embrace it even. The best strategy may be to stop thinking of it as a canoe race and think of it as one of those adventure races that have become all the rage.
Read about Tough Mudder, for example, and a low-water Kenduskeag suddenly seems a little more do-able. There will be more shallows than usual, no doubt — and some of it is likely to be REALLY shallow. More rocks to navigate around. Some of them you might have to haul your boat over. But it still won’t be the Tough Mudder. No one will have to run 12 miles (half of it up a mountain). There will be no fire rings to leap through. No belly-crawling, wall-climbing, ice-water dunking, monkey-bar traversing. or mud-slogging. Well, maybe some mud-slogging.
I’ve stayed up a few nights scouring the web for the secrets of paddling in shallow water. I’ve looked at kayaking, canoeing, rowing, and yachting sites. I even checked out some sites for pilots of large boats. Sorry to say, but there aren’t any secrets. Shallow water is shallow water — and, as is explained below, when you are trying to maintain the speed of your canoe or kayak in these areas, the shallow water literally sucks.
The technical term for this is shallow water drag. As one site states, referring to the work of David Burch, when your boat enters water that is 12 inches deep while paddling at a speed of 3 knots, the resistance increases 90%. That’s nine zero, ninety. Basically it doubles. Another source, also referring to Burch, states that hull speed is reduced by 50% when paddling a kayak or canoe in water that is 2 feet deep.
The loss of speed is due, at least in part, to the increased resistance of the bow wave. In shallow areas, the water can’t move away from the boat as easily and therefore piles up at the bow. For the paddler, this creates the unwelcome sensation that you are paddling uphill.
As if things aren’t bad enough already, shallows can cause your boat to actually sink lower in the water, thus creating even more drag. This is due to the Venturi effect, (told you I had been up late reading) which holds that differences in the speed that water moves creates differences in pressure. In shallow water, the water that passes under your hull has fewer places to go and thus must move at a higher speed, which in turn creates an area of relatively lower pressure, which results in your boat sinking deeper. The faster you go, the more your stern will sink or squat down into the water. Isn’t that just great!
Still another factor, one that you can actually do something about, is called bank suction. I’m not making this up. According to the article at Don Fleming Yacht Services, “Bank suction starts when a vessel strays too close to a bank, restricting the water flow on its bank side. The water-flow velocity increases, causing the water between the vessel and the bank to squeeze out of the area faster than it can flow back in. This causes the water level to drop between the vessel and the bank, and consequently the vessel is pulled sideways into the low-water area.” Unfortunately, it doesn’t just affect large vessels. Watch for this, especially when rounding a bend in shallows. I’ve felt the stern of my kayak being pulled toward the bank just as is described above.
A few suggestions for this year’s Kenduskeag Stream Canoe Race:
(1) Seek deeper water, even if you have to paddle out of your way to find it.
(2) Back off your pace a bit as you approach a portage or a shallow area that you plan to haul over. The time you will lose by doing this is generally less than what you would lose by arriving already out of breath at the portage.
(3) Don’t expend too much energy in shallow areas. The laws of physics will prevent your boat from gaining much speed there, no matter how hard you paddle.
(4) When approaching shallow areas that are followed by deep water, you may want to try increasing your speed enough to “pop” your hull ahead of your own bow wave. Experienced racers talk about this, but I’ve never yet seen it done.
(5) Attach a rope to your bow that can be used to pull your boat through areas that are too shallow to paddle through.
(6) Don’t try to pass another boat by going through the shallows on the the outside of a turn. See the description of bank suck above.– only imagine it being amplified by the effect of the other boat.
(7) Flip flops won’t make it. Wear something sturdy on your feet and consider something that will protect your legs as well. Shin guards (no joke) would probably work pretty well for reducing the rock-inflicted bruising you might get when walking or running through shallows.
(8) Leave your watch at home. No records will be set this year. Not the kind you want to set, anyway.
If you can’t paddle, run. If you can’t run, walk. Don’t stop until you get to the tent with the food in it. That appears to be a winning strategy for this year’s race. The 2012 Kenduskeag Stream Canoe Race: it will be an adventure.