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2006


BUYER’S GUIDE


E L EME N T S O F C A N O E D E S I G N :


THE DIMENSIONS AND SHAPE of a canoe define its performance. Every canoe design blends innumerable variables to produce a ca- noe with specific characteristics such as stabil- ity for birding, manoeuvrability for whitewater or speed for marathon racing. Complicated? On a designer’s drafting table, yes. The basics, how- ever, are not.


DIMENSIONS


Length, width and depth are the rough indica- tors of a canoe’s speed, stability, capacity and seaworthiness. Changing any of these dimen- sions will have a corresponding effect on per- formance.


LENGTH = SPEED Length is the primary factor in determining speed. Given two canoes of different lengths, with all other specifications being the same, the longer canoe will be faster. It will also track better (tracking means going in a straight line) and carry more gear. Shorter canoes will be lighter and more manoeuvrable. The longer-equals-faster equation is only


helpful up to a point, beyond which a hull’s optimal cruising speed gets faster than most people can paddle. Lengths of 16 to 17 feet are standard because this is the hull length that cruises most efficiently at tandem paddling speed.


WIDTH = STABILITY The boat’s width and cross-sectional shape are the primary determinants of stability. A wider canoe will generally be more stable. Width, also called beam, is given in two measurements: gunwale width and waterline width. The water- line width has the greatest influence on perfor- mance because this area forms the footprint of the boat—the width of the boat actually in the water. Wide-beamed canoes offer great stabil- ity but also present greater resistance to the water. Narrow canoes may be less stable, but are more efficient and faster.


1 8 n C A NOE ROOT S early summer 2006


DEPTH = CAPACITY AND DRYNESS Depth refers to the distance between the bot- tom of the hull and the top of the gunwale. Depth is typically measured at the bow, centre and stern of the boat. The amount of depth in- fluences the freeboard—the distance between the waterline and the gunwales. Greater depth allows for increased carrying capacity and bet- ter water-shedding ability. Deeper canoes, however, can be harder to handle in windy conditions and will be heavier.


LxWxD = CARRYING CAPACITY Taken together, the basic dimensions add up to a canoe’s volume—the total amount of internal space. Carrying capacity is measured in different ways, but typically refers to how much weight the boat is able to displace while maintaining at least six inches of freeboard. Carrying capac- ity can be increased by making the boat wider, longer or deeper. Widening without adjusting the length increases drag, reducing efficiency. Increasing the length is usually the best overall solution, while increasing the depth can help as well. This is why cargo-hauling tripping boats are long and deep but not excessively wide.


SHAPE After the raw dimensions of length, width and depth, canoe performance is determined by hull shape. Front, side and overhead views of the boat give you cross-section, rocker, hull symmetry and taper.


CROSS-SECTION: INITIAL AND SECONDARY STABILITY The cross-sectional shape of the bottom and sides of the canoe will influence its perfor- mance, especially its stability. Stability is divid- ed into initial (primary) and final (secondary). Initial stability is what you feel when you first


get into the boat. In a boat with great initial stability, you can stand up and walk around. It takes a lot of effort to flip this boat on flatwater. It resists leaning until it reaches a point of no return, beyond which it quickly upsets with-


The secret to unde


out much warning. That’s because secondary stability was sacrificed for the stable platform providing initial stability. Secondary stability refers to how the boat


behaves as it tilts. A boat with great secondary stability feels stable and predictable when on a lean. This is a useful characteristic for whitewa- ter moves, rough-water paddling and soloing. Flat-bottomed canoes offer great initial sta-


bility at the expense of speed and rough-water performance. Very secure on calm water, they’re great for sportsmen and recreational paddlers. Round-bottomed boats are the other end of


the spectrum. Perfectly rounded bottoms allow for clean entry and exit lines and minimal sur- face area in the water. They have great speed and efficiency but virtually no initial stability. This is why rowing shells are round-bottomed but canoes, except for a few fast, specialized designs, usually are not. Most canoe designs are a compromise be-


tween flat and round, with shallow-arch or shal- low-V bottoms. These designs sacrifice varying degrees of initial stability for good secondary stability and all-around performance. The cross-section of some canoes is modified


by the addition of a keel. A keel is a moulded ridge or attached piece of material that runs the length of the canoe on the bottom outside of the boat to help the canoe track and resist the influence of crosswinds. Keels are most often found on short, wide canoes used for recreation and sporting. They are undesirable in whitewater because they reduce manoeu- vrability and are vulnerable to rocks. The sides of the canoe are either flared, turned-


in or straight. Flared sides shed water. Tumblehome describes the shape of a canoe with turned-in sides. Tumblehome results in a narrower beam at the gunwales making it easier for the paddler to reach over the side of the canoe when paddling. Straight- sided canoes are a balance between the paddling efficiency of tumblehome and the dryness of flare. Canoe designs will incorporate one, two, or all three of these in different areas of the hull.


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