Your #1 source for kayaking and canoeing information.               FREE Newsletter!
my Profile
Paddling Articles In the Same Boat

The Boat Who Couldn't Sink

Flotation Made Easy

By Tamia Nelson

March 9, 2004

Does your boat float? Sure it does — when it's upright, and when the water's where it's supposed to be. But what happens if you take a big wave over the gunwale? Or miss a brace on your way out of a hole? Or slice your hull open on a sharp rock? Will your boat still float? It ought to. Yet many canoes and kayaks don't.

Of course, no properly-built boat will sink outright, even when swamped. All new boats offered for sale should have enough flotation to insure they won't head straight for the bottom, even when they're filled with water. Despite this, there's a world of difference between "not sinking," on the one hand, and floating high and dry, on the other. Why is this important? A boat full of water is a boat on a trip to nowhere, enormously heavy and disturbingly unresponsive. And it's dangerous, too, particularly in a fast current. A swamped tandem canoe weighs about a ton. Imagine what happens when you find yourself pinned between that canoe and a midstream rock. Unless you're Arnold Schwarzenegger, it could be the last time you get to say, "Hasta la vista, Baby!"

Even if you never find yourself in this predicament, hauling a swamped boat to shore is a big job — and once you've got it there, your work has just begun. You now have to empty it of water, without damaging either the boat or yourself in the process. Bailing a canoe or kayak while standing in the gentle wash of kiddie surf on a warm beach is little more than an inconvenience. In fact, it can be downright fun. But trying to empty a canoe perched on a partially-submerged boulder in the middle of a Class III rapids is a whole 'nother scene. And bailing any boat while you're treading water off a lee shore in half a gale is no fun at all.

It's the old "ounce of prevention" number. Your boat needs more flotation than it had when it was sitting on the rack in the dealer's showroom. Most — but not all — whitewater boaters and sea kayakers realize this. Anyone who runs turbulent rivers, or who makes frequent open-water crossings on oceans or lakes, can expect to capsize sooner or later. Yet flotation is just as important to folks who never leave Golden Pond. Expedition paddlers and whitewater boaters almost always travel in groups. Help is usually close at hand. But what about the angler drifting a quarter of a mile from his camp dock on a blustery spring day, only to be caught by a gust of wind from an unexpected quarter? One minute he's rummaging in his tackle box. The next minute he's in the cold water, sputtering and gasping. All he can see of his canoe are the gunwales. Suddenly, that quarter-mile starts looking mighty far. No surprise, eh? When your world turns upside down in an instant, even the middle of a farm pond can be a mighty lonely place. That's why every paddler needs to give some thought to…

Packing Air

Canoes and kayaks require slightly different approaches, but the principle's the same for both. The key is displacement. Water is heavy. Air is light. Trapped air displaces water. The result? Your swamped boat floats higher. It's easier to control and simpler to empty. And just how do you trap air? Watertight compartments are one way. But watertight compartments can fail. Remember Titanic? Plastic foam is another. But plastic is heavy, vulnerable to attack by solvents and sunlight, and more or less rigid. Rigid is good for some things — whitewater boats use foam pillars to support their decks — but not so good for others. If you fill your boat with foam for a whitewater weekend, you've got a big removal job ahead of you when you want to go canoe-camping.

What's the answer? Float bags. They're not much to look at. Just big inflatable pillows made from urethane-coated nylon, vinyl, or some similar material, in a wide range of shapes and sizes designed to fit in every corner of both canoes and kayaks. A small valve permits easy inflation. (It's easy if you haven't eaten in the last hour, anyway. Just pucker your lips and blow.) Another, larger valve facilitates rapid emptying.

Outfitting a canoe with float bags is pretty straightforward. Simply add bags anywhere there's open space. Small, triangular bow and stern bags are probably enough on Golden Pond. Whitewater boaters will want to substitute larger end bags, adding another big float bag amidships to fill the yawning gap between paddlers in tandem boats. (The foam saddle used by many solo canoeists also adds flotation.) There are narrower bags for boats with central braces. Kayaks aren't that much different, though they require more careful fitting. What works for a 17-foot Greenland-style sea kayak won't work for an 8-foot creek boat. Many touring boats also have watertight compartments. If these are filled with gear packed in waterproof bags — test any waterproof bag regularly, just to be on the safe side — there's no problem. If the compartment is empty, however, it's best to add flotation. No waterproof hatch is completely bomb-proof, and even conscientious boaters have been known to leave them loose. (Who, me? Certainly not. Well, not very often, anyway. But once is enough.)

A word of warning: Balance and symmetry are important considerations when adding flotation, particularly in kayaks. If a kayak has just one end bag, and if the boat capsizes and fills, the only part you'll see above water is the end containing the bag. Your kayak is now a nun buoy. This rather unsettling phenomenon has been dubbed "Cleopatra's Needle." Frankly, I'd rather be bitten by an asp. Smart paddlers test their flotation before they need it, deliberately swamping their boats in friendly conditions, with a couple of buddies standing by in case things don't go according to plan. Sound like a nuisance? It is. But it's a lot less trouble than a funeral.

Here are some examples of balanced flotation:

Air Freight

Is it really this simple? No. In addition to packing air, you'll need to…

Get a Grip

All the float bags in the world won't keep you afloat if the bags themselves don't stay put. They're float bags, after all. If they're not tied down — or otherwise secured — the first wave to come over the gunwale or cockpit coaming will float them away. Canoes are especially vulnerable. It's just not enough to wedge bags under a deck or thwart. Nor can you rely on the corner grommets that some manufacturers provide. Truth to tell, such fittings are best ignored. Grommets tear out easily, often tearing the float bag into the bargain. Lashing does a better job. Crisscross nylon cord over your bags, then tie the ends off to D-rings located on or near the gunwales. Longitudinal webbing straps secured to floor anchors also work well. You'll find "tie-down" kits in most outfitter's catalogs, right alongside the float bags.

If you've mastered the bowline, tautline hitch, and round turn with two half hitches, however, and if you're the do-it-yourself type, you don't need to buy a kit. You'll manage just fine with materials from your local hardware store. The anchors are the biggest problem. Owners of "tin tanks," fiberglass boats, and wood-canvas canoes will have an easy time of it. Others will have to proceed more carefully. Before you attach screw fittings to extruded vinyl gunwales, for example, check to see that they have a metal reinforcing rail. Not all plastic gunwales do, and if yours don't, you'll need to add backing plates to keep your anchors from pulling out.

Whatever tie-down method you decide on, it's a good idea to make sure that no fittings will chafe your hands as you paddle. You should also give some serious thought to the danger of entanglement. All lashings present some risk. That's one reason why no prudent boater ventures out on the water without a good knife.

Kayakers needn't worry quite so much about their float bags floating away, of course. The lids on their boats keep properly-inflated bags in place in all but the most extreme conditions. You're not satisfied with that? Neither am I. Longitudinal webbing straps add an extra measure of security.

And speaking of proper inflation, don't ignore temperature shifts. When you go into the garage at zero-dark-thirty to get ready for a day on the water, it's likely to be chillier than it will be at noon, and air expands when heated. Check your float bags from time to time throughout the run, letting air out or topping up if necessary. You've got it right if the bags feel firm. Rock hard is too hard. You should be able to make the surface "dimple" with light finger pressure.

What do you do if a bag is losing air? First, make sure the valves are closed. Then start hunting for punctures or tears. You should always bring a patch kit with you. (The instant "glueless" patches used by cyclists will stop most pinhole leaks, though you'll have to dry the surface before applying the patch.) If your destination lies at a different altitude than your garage, you should keep that in mind, too. Reduce pressure if necessary as you go higher; add air when you descend.

OK. Extra flotation is a good thing. But what if your budget is tight? Commercial float bags aren't exactly cheap. Don't give up the ship, though. You can still…

Float Alone

Inner tubes were once the cash-strapped canoeist's flotation of last resort. But big inner tubes aren't as easy to find as they used to be. You may want to look closer to home, instead. A rucksack or other pack filled with milk jugs is a pretty good substitute for a float bag. You don't have enough packs? Then use old pillow cases or heavy-duty plastic trash bags. Not enough milk jugs? The plastic liners from boxed plonk also make good flotation modules, though they'll need to be inflated first. This can be a bit tricky, but it's not really too much trouble. There's a bonus, too. How many float bags come filled with something you'd want to drink, after all? And we've only just touched on the possibilities. Any watertight plastic container is potential flotation. Even the soap-bar-sized, air-filled bladders that some shippers use to protect delicate merchandise will work. They're certainly strong enough. I just tried one to see if it would support my weight without breaking. It did.

In any case, whether you fill your packs with milk jugs, wine bladders, packaging material, or ping-pong balls, you'll still need to lash them in place. Apart from the fact that any flotation that floats away is no good to you or your boat, you'll want to make certain that your recycled plastics don't add to the world's burden of floating trash. Sea turtles and other marine animals often mistake plastic for food, with deadly consequences.

You'll also want to keep your float bags out of the landfill as long as possible, especially if you've paid good money for them. It only takes a little…

Tender Loving Care

Sunlight kills plastic, so protect your bags from the sun whenever possible. And guard against overinflation. (There's no need to let all the air out between trips, however.) It's also a good idea to inspect the bags carefully several times during the season — pay especial attention to seams and areas subject to chafe — and to clean them before putting them away. Mild detergent works fine. Dry the bags thoroughly, then store them flat or loosely rolled. Don't fold them unless you have to. If your bags spend the winter in an outbuilding, it's best to keep them in mouse-proof containers. Do you live north of the Mason-Dixon line? No problem. Even when winter temperatures dip down to -40, I've seen no evidence of cold cracking during storage. I always allow bags to warm up before unrolling or inflating them, though.

That takes care of looking after your bags between trips (and between seasons). But what about all those times when you'll be…

Carrying Gear?

Flotation is one thing. Gear is another. And never the twain shall meet, right? Wrong. The catalogs are full of packs and gear bags advertised as "waterproof." Luckily, many of them really are. (A quick dunk in the pond will tell you if you've made a good choice.) These bags work fine as flotation. Yes, your gear weighs more than air, but unless you're hauling gold dust, it weighs a lot less than water. One of my 3.5-cubic-foot waterproof packs — that's about 6,000 cubic inches, or around 100 liters — would weigh over 200 pounds if filled with water. Stuffed with gear it usually weighs only half as much. The difference between the two weights is a measure of the buoyancy of the loaded pack when immersed.

The upshot? You can freely substitute waterproof gear bags for float bags. You still have to lash them down, though. And if you want your boat to rise to the waves, it's a good idea to keep your heaviest gear out of the ends. But that's just common sense, isn't it? Canoeists can simply mix and match float bags and waterproof packs to meet their needs. Kayakers have a slightly harder time, but they can make room for gear bags by partially-deflating their end floats. Or they can go the whole hog, substituting "storage-flotation" bags for their regular float bags. Many of these stow-float bags depend on zip fasteners, however, and sand and zippers don't mix. A little care goes a long way here.

High and dry. That's something no boater wants to be. Until he's shipped a big wave over the bow, that is, or capsized in a turbulent river. Then "high and dry" starts sounding mighty good indeed. Extra flotation makes all the difference. Don't leave home without it.

Copyright 2004 by Verloren Hoop Productions. All rights reserved.

Sponsored Ad:
Follow us on:
Free Newsletter | About Us | Site Map | Advertising Info | Contact Us


©2015 Inc.