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 Post subject: symmetrical vs. asymmetrical !!
PostPosted: October 21st, 2004, 7:58 pm 
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Joined: September 26th, 2004, 7:13 pm
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Location: Southern Ontario
Hello guys and gals. I've never paddled an asymetrical canoe since I own and love prospectors. Some of you must have views on the advantage/disadvantage of such canoes. Can they be used for tripping? Stormy.


Last edited by stormy on October 22nd, 2004, 6:46 pm, edited 1 time in total.

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PostPosted: October 21st, 2004, 8:16 pm 
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Stormy,
It is more than theory that the angle of entry (front of your canoe) makes a difference to the amount of energy needed to propel it.
Proof: Take the asymetrical canoe and paddle it with the fat end forward and you find the difference in the dull way it cuts through the water.
The symetrical canoe is versatile, and the price paid for versatility is the compromise that the angle of entry is equal on both ends, I think.
Jan

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PostPosted: October 21st, 2004, 8:40 pm 
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I think we sorta have been here before but I dont think the librarian is in..

Are you in Barbara?

Of course you can use an asymmetrical canoe for tripping but there is quite a variation in "asymmetric canoes". Basically the widest part of the boat is not in the middle..Typically its a little back, but it can be a little forward too. End shapes can be anything. The stern may be skegged a little for tracking and there may be less sheer in the stern. There are a host of other differences possible.

In my experience I find that the "symmetrical" canoe (and I wonder if there really is a TRULY symmetrical boat) is the one that paddles the same whether you are facing forward or occasionally have to face backward as in soloing from the bow seat (which I personally dont care for as it often leaves me with a really long reach to get in front of the pivot point).

My Dumoine is asymmetrical. It is a poor choice to paddle solo from the bow seat as the stern height is low and the fuller end is now at the wrong end, amongst other things. Thats why it has a kneeling thwart, so I can solo it facing the same way as when going tandem.


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PostPosted: October 21st, 2004, 9:06 pm 
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Kim Gass wrote:
I think we sorta have been here before but I dont think the librarian is in..

Are you in Barbara?

Yar, here I am............bored, so did a search for y'all

Title of thread: symetrical vs. asymetrical

If you're dedicated and determined, go to the "search" and type in either "symetrical" or "asymetrical" (correct spelling optional) and go nuts.....or blurry eyed.

Barbara

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PostPosted: October 21st, 2004, 9:20 pm 
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Yeah, I think that the difference between a symmetrical or asymmetrical canoes is much less than one might expect. I agree with Kim that a symmetrical canoe is one that theoretically could be paddled backwards as efficiently as forwards. But as one heads toward more performance oriented flatwater boats they are often asymmetrical. I own boats that fit into both categories, and though the asymmetrical boats are faster, the speed is more related to the length/width ratio, and that the boats design was tailored towards forward speed than to the fact that the canoe is asymmetrical

PK


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 Post subject: symmetrical vs. aymmetrical
PostPosted: October 22nd, 2004, 1:46 am 
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Although I am convinced that asymmetrical so called 'Swede' designs
can be better for easier and relative dryer paddling (forward), the
big problem is perhaps that it is very difficult to design a truly
good asymmetrical canoe. You really have to know what you are doing
when you are designing an asymmetrical canoe. And I am afraid with a
lot of designs most of the test paddling is left to the satisfaction
of the customer... With probably as a big handicap that when you
instantly notice a real performance advantage, the design may be
extreme and not a good performer at some other points, as I have
experienced with some asymmetrical designs that I have owned. Good
asymmetrical designs have perhaps too subtle performance advantages,
only to be noticed when you have paddled them for several days in
all kind of circumstances?

What I do have found to be a real 'disadvantage' of extreme
asymmetrical canoes though, is when portaging one in a very hard
wind: there they seem harder to control than symmetrical canoes. Or
is this my imagination? I wonder if other people have experienced this.


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PostPosted: October 22nd, 2004, 10:03 am 
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I'm not sure about the portaging comfort being worse in windy weather, but the portaging yoke that's in asymmetricals is often very close to the solo kneeling thwart, resulting in a tight fit when getting in and out, and not being able to sit down comfortably and stretch out to relax every once in awhile. Some have even built removeable yokes so they can alternate between kneeling and sitting which seems to be added work on each portage.

Asymmetricals are also said be more sensitive to fore and aft trim due to the narrower bow section and it seems that level trim is needed to maintain the efficiency the hull was designed for. I don't know whether any difference would be noticed in water resistance, maybe more with the ability to cope with changing wave and wind conditions... and on a long trip maintaining proper trim might be forgotten at times, so the hull isn't being used as efficiently as it could be.

I agree that coming to know the finer points of paddling a particular design only comes with repeated use over time and one test paddle will only be a rough introduction to how the boat will perform overall, and how comfortable one will be with it.

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PostPosted: October 22nd, 2004, 6:17 pm 
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Thanks Kim, Barbara.I suppose I should do a search before I post a question. I'm sure it will save everyones time and I'll find most of what I'll be looking for. Now I'll check out that thread Barbara found. Stormy.


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PostPosted: October 22nd, 2004, 7:02 pm 
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Dang, stormy, don't stop asking questions! Even if someone says "do a search" or if someone like me gives you links to previous similar threads, we need questions being asked. You see the answers people gave you already? They may have already contributed to just such a question before, but that doesn't mean they aren't ready, willing and able to answer again.

Sometimes the search can be a difficult thing, due to the way you enter your criteria. For example, the spelling of asymetrical......spelled correctly brings up one set of threads, spelled incorrectly will bring up a whole different ball of wax.

This is cabin fever season......for us folks who live in hard water country or who are too chicken or ill-equipped to go out into the cold. We need new diversions (topics of discussion). Just look at our silly fussing and feuding over the "newest topics" hullabaloo. :doh:

For your viewing pleasure, I give you this link:
Canoe Physics

He, he, he. (evil laughter) Hope you have plenty of endurance to get through that one! :lol:

Barbara

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PostPosted: October 22nd, 2004, 8:37 pm 
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Asymmetrical or symmetrical refers to the waterline profile. Sometimes its really hard to figure out whats going on from topsides... The thwart/seat arrangement in my "symmetrical" boats is decidedly not asymmetric...as for you folks with portaging problems, its most likely because your yoke isnt at the pivot point, or maybe you like to dangle six PFD' s from one end!
I can relate to frozentrippers scenario. In the Dumoine there isnt alot of space between the kneeling thwart and the yoke, but I have yet to get stuck. I really do appreciate the support that that thwart gives me. It really hurts after a time to sit on your ankles. You really should be cozied up to the pivot point, hence the relative closeness of that kneeling thwart. Even then I think its too far back..Its hard to keep the boat within the hula hoop for pivots.
Someone at the CRCA must have had a long winter to think of that maneuver. Three times one way and three times the other?


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PostPosted: October 25th, 2004, 7:08 pm 
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No matter how a boat is designed or built it rarely, if ever, is symmetrical.

Why? Because it rarely is ever trimmed dead level fore and aft.

There are some simplistic ways of looking at the problem. First, the bow and stern do entirely different things. The bow displaces water and the stern allows it to flow back to the normal level. If both ends do their job properly you have something special. Only in very unusual circumstances will the best shape for both be the same.

The other simplistic view is that it really may not matter that much to you. A really well designed symmetrical boat is a joy to paddle just as a well designed assymetrical boat is a joy to paddle. Most people are not sensitive enough to detect the difference.

If squeezing the absolute most efficiency out of a canoe is your goal (particularly for tripping) then the assymetrical hulls usually make sense. I say usually because not every boat suits every paddler.

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PostPosted: October 26th, 2004, 3:02 pm 
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Jwinters wrote:
No matter how a boat is designed or built it rarely, if ever, is symmetrical.

Why? Because it rarely is ever trimmed dead level fore and aft.


I fully agree. I work hard to paddle a symmetrical canoe as effectively in reverse as forward, and regardless of how much you do it.... the boat does not paddle the same. But the boat is still a joy to paddle and I can't think of any asymmetrical canoe that I would enjoy to paddle as much in reverse.

Jwinters wrote:
If squeezing the absolute most efficiency out of a canoe is your goal (particularly for tripping) then the assymetrical hulls usually make sense. I say usually because not every boat suits every paddler.


Again, I agree with both of these statements. There are people who demand the utmost in performance from a hull. One sees the application of asymmetry to canoes mainly in solo canoes, and in tandem canoes designed primarily for flatwater tripping. But a good paddler (or team in the case of a tandem) in a symmetrical canoe could easily overcome less talented paddlers in an asymmetrical canoe.

Thanks once again John for adding your expertise to this discussion. I always enjoy reading your discussions on the hydraulics of the canoe.

PK


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