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 Post subject: hull weight vs. design
PostPosted: October 20th, 2007, 7:44 am 
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Joined: April 22nd, 2003, 8:26 pm
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Location: London, Ontario, Canada
Curious, with the ever lightening of canoes, will there be a future correction in hull design?

-I have heard of (ultra light) canoes hitting the under 30 lbs weights.

-this would be great on the portage, but what would it be like on the water?

-how would an ultra light canoe track ? in a wind? empty of gear?

-would there be a need for the possibly of a deeper (tracking) hull?
(setting a side the keel debate)


Doug


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 Post subject: canoe weight
PostPosted: October 20th, 2007, 9:50 am 
Displacement of a canoe includes the weight of the canoe, so I suppose there will be a (small) correction necessary to get the same course stability as the heavier version.

Dirk Barends


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PostPosted: October 20th, 2007, 2:25 pm 
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Location: Grand Haven, Michigan U.S.A.
We've had this discussion before. Personally, the boat accounts for less than 1/3 the total displacement weight even with the lightest paddler and the heaviest canoe. So the 10 pounds the paddler puts on in the winter has as much an effect as the 10 pounds in the canoe, or the 10 pounds of day pack you place in the canoe. Can you feel a difference with a light day pack in the canoe over when it's not there? There are times where it does affect trim, but I think that the weight of the canoe has less impact.

I do think that you can feel the momentum of a heavier canoe in a spin, but I I don't personally think it matters.

PK


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 Post subject:
PostPosted: October 20th, 2007, 6:41 pm 
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Joined: September 28th, 2004, 6:52 am
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Most designers do not design around the displacement so it is unlikely there will be any change in designs. As PK says, the boat is but a small part of the total displacement.

In my studies I have found that, for most people, a displacement difference of +10% /-20% is not noticed. So even a 20 pound difference in hull weight is unlikely to be sensed with two possible exceptions - that of inertia in turns and pitching moment in waves. If the lighter displacement is uniform over the entire boat or greatest in the ends it will have less inertia and the boat will feel more responsive and wil pitch less in waves.

If anyone says they designed a boat around its lighter weight they are probably blowing smoke. The key question is, "What is the designed displacement because a properly designed boat is designed around that not just the hull weight.

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