Sakaana style canoes are a very stable, small vessels created by a group of native
Indians near a fishing village in the Alaskan Yukon.
This vessel was rediscovered in the 1800's and the design has been passed
down . No longer is the prized fishing boat constructed of birch slats
and seal skins, today it is made of hand-laid fiberglass. However, the concaved bottom that created the incredible stability of the original Sakaanas is still the most important asset of its design today. The concaved cavity that runs along the bottom of the boat from just after the bow to just before the stern is the secret of its unbelievable stability. The cavity causes three important design functions to happen at the same time. First, the boat carries the weight of the passengers and gear on the outside edges of the vessel instead of the center line keel. This causes the boat to react more like a pontoon, catamaran, or tunnel hulled vessel rather than a canoe or kayak. Second, the concaved bottom provides a larger surface area to support the weight of the boat, passengers, and gear than a flat or round bottom boat. This lets the Sakååna float in the water but does not decrease the width or length of the area of the bottom that is in contact This is not true of other small boats, canoes, or kayak style vessels. The shallower the round bottom style of vessel rides, the more unstable it becomes because the vessel is riding on its center keel instead of its outside edges. Third, the cavity fills with water and creates a vacuum that literally keeps the boat from tipping over in calmer waters. A good comparison of this effect is lifting of an upside-down glass that is filled or partially filled with water out of the kitchen sink. As the glass is being lifted the water contained in the glass is being lifted with it, increasing the weight of the glass being lifted. When the edge of the glass is at the surface of the water, a vacuum is created that increases the amount of force that is needed to lift the glass out of the water. This is the same effect the water-filled cavity under the Sakååna style boat creates to help keep the vessel from overturning. As side note, canoes have been found that date back to the Neolithic period which dates to roughly 6000 B.C. |
