As with life in general, simple answers just don't apply.

The flat bottom will tend to remain parallel to the surface of the water, and just below it, (unless you are carrying a very large number of helium balloons).  If you are canoeing on calm, flat water, then the flat bottom will make for a much more stable ride.  You can shift your weight to greater extremes and not feel that the canoe will rotate under you and tip you out.
Another way to look at it, is that it is easier to keep your centre of gravity over the flatter boat whereas the rounder hull seems to slip out from under you, leaving your centre of gravity over the edge.

If you are in rougher water, the situation is more complex:
If you are on the side of a wave, the water surface, and thus the flat bottom of the boat, may be tipped at a considerable angle.  If you are sitting perpendicular to the bottom, then you might find it very difficult to keep your centre of gravity over the boat. (Depending on the severity of the wave and the height of your seat)
The round bottom boat will tend to rotate so that the water is higher on one side than the other, but it means that you will find it easier to remain vertical and keep your centre of gravity over the boat.

If the boat takes on water, the water will form a shallow layer across the entire bottom of the flat bottom boat, but it will tend to concentrate and be deeper, down the centre line of the rounder boat.
In flat water, this means you have a greater variety of depths of water to place your feet in, which may not be of much concern to you or your feet.

In rough water, the deeper water around the centre line will tend to pull the centre of the boat down, rotating the boat to keep the bottom down.  This will tend to keep the paddler above the centre line of the canoe and in a reasonably vertical position.

As the flat bottom boat tips with the surface of the wave, the shallow pool will suddenly rush to the lower side, and the weight and momentum of it will increase the tendancy to tip.  As the boat goes over the wave and tips the other way, the water will suddenly surge to the other side.
The momentum of the water will act to enhance the extremes of the boat motion which will force you into a position that continually places your centre of gravity beyond the edges of the boat.  This, of course, increases the likelyhood that you will get to use the PFD that you so-wisely are wearing.

The water in the round boat will also oscillate around the centre point, but due to the shape of the hull, the oscillations will not be as severe and the boat will have a greater tendancy to keep its occupants in stable positions.
In reality you will select a canoe that best suits how you will use it, and it will likely be a compromise shape, between the extremes.  If like me, you like to glide through the backwaters on a calm day and examine the flora and fauna beneath you, you will select a flatter canoe.  If you like more adventure, or perhaps you want more speed, then you will want a different style.

Each shape has its advantages and its disadvantages, there is no single best canoe shape or style.

To see some diagrams representing these ideas, click here.  For more information on shapes and Voyageur canoes click here.
 

Back to Canoe information.

Canoe Related Terms

Parts of a Canoe
Hull	The main body of the canoe which displaces and parts the water.  The displaced water provides the buoyant force
Gunwale	Also called gunnels or rails, these are the upper edges that surround the upper part of the hull.  The gunwale often consists of 2 parts; the inwale which runs alaong the inside of the hull and the outwale which runs along the outter edge.  They supply suport and rigidity to the hull.
Planking	These are the wooden strips which run the length of the hull and give it form.
Ribs	These are the narrow cross-members which follow the shape of the hull; hold its shape and give added rigidity to the bottom.
Cover	The cover is the waterproof layer stretched over the, usually wooden, frame.  Fibreglass and aluminum boatsdo not require a cover.
Keel	This is a narrow protrusion on the bottom of the hull, running the length of the canoe.  It helps prevent side slip and accepts most of the wear and abuse suffered by the bottom.
Bow	The front end of the canoe when moving forward.  Normally the end with the greater distance between the first seat and the pointed end is considered to be the bow.
Stern	The end of the boat opposite from the bow. (ie the back end)
Stem posts	These are the narrow strips of wood, at the bow and stern, to which the ends of the planking are attached.  They provide strength and curvature to the ends of the canoe.
Decks	These are basically horizontal triangles of wood that sit between the gunwales at either end.  They provide had grips  for carrying the canoe and a place to attach a rope.
Seats	These are wide cross members usually positioned just below the gunwales that paddlers can sit on or lean against.
Thwarts	These are one or more cross-members positioned approx. at gunwale level.  They provide support to the gunwales and sides of the hull.
Stem bands / strips	Usually brass or aluminum strips attached to and following the curvature of the stem posts.  They may extend the full length of the hull and they help preven wear to the hull.
Floatation	In fibreglass and aluminum canoes with no natural buoyancy, the ends usually contain a poured in place piece of foam to provided added buoyancy.
Floor  Racks	These are strips of wood that form a protective covering on the inside of the bottom of the hull in some wooden canoes
Yoke	This is a contoured form, designed to comfortably fit the shoulders, which supports the weight when carrying the canoe

Boating related terms

Access point	A location from which a boat may be launched or landed
Aft	Toward the stern or rear end of the boat.
Air lock	The suction within a canoe when it is overturned in the water that makes it difficult to right.
Bang plate	A metal strip on the leading edge of cutwater, bow & stern, that protects the hull, also called a bow plate.
Beam	Width of the craft at the widest point
Bilge	The interior of a canoe located below the waterline
Bilge keel	A extra keel, one on each side, located just inside the chine to protect the fabric on canvas canoes.
Blade	The flat section of a canoe paddle.
Buoyancy chambers	Air tight chambers in fibreglass and aluminum canoes to provide buoyancy.  Also called air tanks.
Carry	A portage, in which the boats are carried around some obstacle
Channel	A navigable route among obstructions in a waterway
Chine	The curving section of a canoe's sides where is bends or merges into the bottom.
Chute	A accelerated section of a stream where the current is compressed between obstructions which causes ti to accelerate
Depth	The depth of a canoe, measured vertically amidship.  Sometimes the depth is measured at the ends which can be misleading.
Displacement	The weight of water displaced by a watercraft and its cargo & crew.
Draft	The depth of water required to float a craft, or the vertical distance between the waterline and the keel.
Eddy	A section of current, downstream of an obstacle, where the water tends to move in circles.
Feather	To bring a paddle forward with one edge leading, thus reducing the resistance by water or air.
Ferry	Holding a canoe at an angle to the current and paddling so that the canoe sets over across the current
Fore	Toward the front end of the craft.
Freeboard	The height of a canoe's side above the waterline, measured amidship.
Gradient	The average rate of drop in a river usually in feet per mile
Grip	Top of a canoe paddle shaft, shaped roughly to fit the hand
Haystack / rollers	Standing waves at the foot of a powerful chute or sluice created when fast-flowing water strikes relatively still water
Ledge	A projecting stratum of rock which confines or partially dams a stream
Open gunwale	Gunwales in which there is a space between the inwale and the outwale to allow drainage of an inverted canoe
Painter	Length of rope attached to either or both ends
Port	The left side of a boat when facing forward.
Rapids	Swiftly flowing water, tumbling with some degree of force among obstacles.
Riffles	Swift, shallow water running over gravel or sand bottom to create small waves
Rips	Moderate rapids
Rocker	Upward sweep of keel line toward both ends of canoe, characteristic of river craft
Shaft	The handle of a canoe paddle between the blade and the grip
Shoe keel	A shallow, wide keel for use on river canoes which may also may be used on lakes. It has a minimum interference while making broadside moves in current
Spray cover	Temporary fabric deck used on open canoes during white water running to keep the craft from taking on water
Starboard	The right-hand side of the craft when facing forward
Stern	Rear or back of a watercraft
Throat	The flaring of the paddle shaft where it starts to form the blade.
Trim	The manner in which the canoe rides on the water
Tumblehome	The inboard curvature of a canoe's sides from the bilge to the gunwales
Windward	The direction from which the wind is coming

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