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PostPosted: June 10th, 2009, 10:15 pm 
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pknoerr wrote:
While canoe efficiency can have an effect, I know that I've personally expended far more energy posting to this thread than I would paddling any canoe for 20 miles on a wilderness canoe trip regardless of design.


LOL, now that's funny, true, and funny, possibly a little bit sad, but funny.

Dave

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PostPosted: June 10th, 2009, 10:29 pm 
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Hey Moonman, I have looked at that canoe, and it does have beautiful lines. How do you find it handles? I suppose you like it as you're working on number two.

Another one I have thought of, partially due to the ease of construction, would be a stitch and glue canoe. At one time there were plans for John Winter's Osprey available as a stitch and glue design. The plans used to be available at Green Valley, but if I remember correctly, they were pulled to redraw the panels as they weren't lining up properly. If John is still around once in a while, is there any prognosis of when those plans will be released again?

Ah, to dream the dream...

Dave

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PostPosted: June 11th, 2009, 9:45 am 
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Hi Dave,

Actually my first canoe was a Winisk (similar to your Temagami, maybe a bit faster, maybe not as stable), the one I'm working on now is a modified Mattawa. The Winisk handles very well, I just recently came back from an Algonquin trip where it did wonderfully (Starting at Tim Lake, through Rosebary, down the Nip, up to Loughrin and Lawren Harris, down Loughrin Creek to Biggar, and across North Tea, with a shuttle back to Tim). I haven't built the Freedom Solo yet, so not totally sure how it handles. Its a Steve Killing design and I have paddled his Freedom tripper before and I like his boats. Also, during the design process, he got input from a bunch of us guys on the Bear Mountain forum - so I think it will handle well. At one time I wanted to build the strip Osprey, but I think the Freedom will have a bit more speed, yet still turn and handle waves well. Besides, I just love the look of that tuck-in! There used to be quite a few images on the Bear Mountain site of the Freedom Solo from various angles and it is a beauty. Everyone over on that site is waiting for someone to finish one and post pics...

Anyway, re the stitch and glue Osprey, I believe Martin Step has some new drawings available that correct a couple things that came up in the first set of plans.

Cheers,
Moonman.


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PostPosted: June 11th, 2009, 6:11 pm 
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Moonman, I'm glad you brought up the Freedom Solo here. I think it is very relevant to the topic at hand.

At first glance, the FS reminds of the DY designed Merlin II. Not just the shouldered tumblehome, but the same basic dimensions and a very similar body plan. Differential sheer and rocker. Elliptical bottom with soft bilges, moderate deadrise, constantly flaring sides right up to the tuck at the shoulder. But in the plan view it can be seen that the FS is very decidedly swede form (actually, this is quite apparent in the other two views if you look at these things a lot).

Despite the slightly longer length and a full 1" wider amidships, the FS only has a 220# capacity at the 3" waterline compared to the Merlin II, with a 240# capacity. This is the result of reduced buoyancy in the bow.

Let's introduce our paddler, a 240# man. As he slips into position in the boat, he is 20# heavier than the boat can carry at the 3" waterline. Therefore, the draft of the boat with him in it will be greater. This will increase both the size of the displacement waves and the wetted surface area. How much will this increase the wave making resistance? How much increase in frictional resistance? At what speeds will it be most significant? Will these increases be enough to offset the claimed increase in speed brought about by the swede form?

We decide to build another boat that will bring the displacement in line with the Merlin II. In order to do this, we increase the length of the boat. (we could increase the beam but that would have a slowing down effect on the hull). Since displacement in a given body shape varies (approximately) as the cube of the waterline length, this would take about an increase of 6". This will increase the frictional resistance because the wetted surface area will be increased slightly. This resistance will increase in a linear fashion as the boat is paddled at higher and higher speeds.

We now take our two boats (first making sure that we paint each one Fire Engine Red :wink: ) and our 240# paddler (a seasoned tripper in prime condition) out for a rigorously controlled series of time trials. After collecting all the data, we analyze it and discover that, sure enough, our paddler averaged 7.3 km/hr in the longer boat compared to 7.4 km/hr in the Merlin II (about a 2% difference). But do we really know why?

Was it the swede form shape or was it the greater length? The difference in length alone would account for a 2% increase (potentially, at any rate). We'll never know for sure since each modification effects other parameters. But the paddler is convinced and chooses the swede form boat because he definitely was faster in it as indicated by the clock.

Sure, I never actually did these time trials, and the actual results would be different (the Merlin II might smoke the lengthened FS), but it can't be denied that, at equivalent displacements, the only way to make the boat asymmetrical is to decrease the beam in one end and lengthen the boat (therefore masking it theoretically faster) or to increase the beam at one end (which will make the boat significantly slower). Either decision results in an entirely different hull, so comparisons are futile.

Note that I didn't mention a scenario where the paddler takes both boats out for a ride on big water in waves and wind and gives his subjective impression at the end of the day. As trippers, I think that would sway us more than anything.


Dave, I'd wait until you actually paddle one of those Osprey's. A stitch-and-glue is a one trick pony, build-wise. No way to modify it like you can a stripper. Yes, a lot cheaper and easier to get to the bare hull stage, but only about 60-70% of the build is involved there. You still have to do all the trim work and varnishing - a lot more time than you think it will take to do a first rate job. Plus, a stripper will be worth a lot more money down the line if you tire of it.

You should check out the Soul-Mate plans at Carrying Place Canoe. It has those sweet DY influenced lines without all the asymmetry, plus, it has more rocker, which in my mind is a very desirable thing. His plans are slightly cheaper and are full sized CAD rendered drawings.

Gotta say, though, if looks alone was pushing the boat across the lake, that Freedom Solo is one sweet looking canoe - asymmetrical or not. If you or Moonman do actually build it, you should build two - one asymmetrical and one not. We'll get together and do the time trials and make up our minds then. :wink:

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PostPosted: June 11th, 2009, 6:48 pm 
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Hey BK,

You might be interested to note that the Freedom Solo comes in two lengths 15' 3" and 16' 2". This is because some heavier paddlers asked for it for total displacement purposes. I believe all the other dimensions are the same so we could try both of them out.

I do agree that sea worthiness - bow width and buoyancy especially - is an often overlooked factor in canoe design - one that often means the difference between being shore bound or paddling...or even worse...still you can have a nice swedeform shape with a buoyant bow...conversely, I have paddled a symetrical boat with a fine entry bow that was crazy dangerous in waves of any size.

Moonman.


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PostPosted: July 21st, 2009, 6:12 pm 
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For those of you that are pro-aysmmetry, y'all are going to love this boat. Yes it is supposed to look like that.

http://www.cboats.net/c_db/list.php?nam ... oat_id=153

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PostPosted: July 23rd, 2009, 6:34 am 
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Quote:
Another one I have thought of, partially due to the ease of construction, would be a stitch and glue canoe. At one time there were plans for John Winter's Osprey available as a stitch and glue design. The plans used to be available at Green Valley, but if I remember correctly, they were pulled to redraw the panels as they weren't lining up properly. If John is still around once in a while, is there any prognosis of when those plans will be released again?


I think we have the problems sorted out. I am not a great fan of S&G but can understand why people want them. Hard to get the same performance as a round bilge boat and that is what led to early problems as I tried to make S&G do what it didn't want to do.

The new version seems to work well according to the people who have built it. Knock on wood :-?

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PostPosted: July 23rd, 2009, 7:06 am 
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BK wrote:

Quote:
Was it the swede form shape or was it the greater length? .


How true. You won't. That , of course , is why we have designers :lol:

With boats it is never as simple as one characteristic versus another. This is why some designers try to supplement their gut feelings with performance prediction programs that can analyze many different factors as a system instead of individual factors in isolation.

The issue with top speed is a good example. In BK's example the test paddler paddles all out - something that is hardly relevant to the tripping paddler. In the all out case the boat should have a high prismatic coefficient and that would probably make more difference than the length alone because it would decrease wave making resistance while not necessarily increasing wetted surface.

Increasing the prismatic coefficient often has more effect when done by filling out the stern sections as it can increase effective waterline length while not increasing resistance since the flow velocity slows as you approach the stern. One need not change the bow at all if you feel you have a suitably designed bow to start with.

The performance (used in a broad sense) of a boat is the sum of many factor. Some are detrimental to resistance and good for something else and vice versa. The end result is a boat that will please some people and inspire derision in others. What matters is if the paddler likes the boat and it does what he/she wants doing. It seems counter productive for paddlers to argue over the merits of specific characteristics in isolation from others. Hopefully they understand the effect of all and have at least made an attempt to understand them all.

One hopes, of course, that the designer did that - after all, that is what he gets paid to do - one hopes :wink:

Unless one has good scientifically obtained proof that one characteristic is superlative in isolation and regardless of all others let me know. Otherwise it remains opinion and is of value to the opinion holder in isolation.

HMMM wish I had said that. :D

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PostPosted: July 24th, 2009, 10:07 am 
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Moonman, not to be picky, but the MR website shows only one Freedom Solo, at one length, 14' 6". Same as my old MR Guide.

I have heard the Freedom Solo described before as lacking enough fullness in the bow. It would not hurt to spread the bow a little with a thwart, and the small increase in bow rocker will not hurt. May try it on my Guide. Another trick is seen in downriver racing, where foam splash rails are glued along the front gunwales. These would not be in the way of my forward strokes, which enter farther from the hull.


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PostPosted: July 24th, 2009, 10:37 am 
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ezwater wrote:
Moonman, not to be picky, but the MR website shows only one Freedom Solo, at one length, 14' 6". Same as my old MR Guide.


Not MR. Moonman is referring to another design with the same name, a Steve Killing boat that was designed for wood strip construction. Plans are available from Bear Mountain.

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PostPosted: July 24th, 2009, 11:10 am 
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:-? Thank you, sir. May I have another?


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PostPosted: July 24th, 2009, 5:32 pm 
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Jwinters wrote:

With boats it is never as simple as one characteristic versus another. This is why some designers try to supplement their gut feelings with performance prediction programs that can analyze many different factors as a system instead of individual factors in isolation.


:tsk: :tsk:

Gut feelings combined with paddler subjectivity? Sounds like a recipe for disaster to me.


Uh... just kiddin'. :wink:


Quote:
The issue with top speed is a good example. In BK's example the test paddler paddles all out - something that is hardly relevant to the tripping paddler. In the all out case the boat should have a high prismatic coefficient and that would probably make more difference than the length alone because it would decrease wave making resistance while not necessarily increasing wetted surface.


Minor quibble here. I said rigorously controlled time trials (as in good experimental design), not rigorous paddling. Note that the speeds I gave are significantly lower than theoretical "hull speed" for the canoes mentioned. The figures I used were plucked from thin air (I can't maintain that pace all day) as estimates of the average speed a prime conditioned tripper (not a marathon athlete) might expect to achieve over the course of a day. All out in total energy expended, maybe, but not even close to top speed (9.6 kmph for a canoe with a 15' waterline).

Quote:
Increasing the prismatic coefficient often has more effect when done by filling out the stern sections as it can increase effective waterline length while not increasing resistance since the flow velocity slows as you approach the stern. One need not change the bow at all if you feel you have a suitably designed bow to start with.


All well and good. That means we can improve the capacity of a symmetrical design by adding buoyancy aft and not affect the efficiency/speed of the hull at all? I can see nothing wrong with doing that, although I suspect that this will affect the water returning at the stern and, perhaps, increase turbulence? If not, maybe we should look at all symmetrical designs with a mind to increase capacity for tripping considerations. This would add a wee bit of weight and decrease the draft (making the boat sail better in the wind when unladen), but a slight adjustment in the depth would compensate for both of these problems. A down side? Wider paddling station at the stern end for one.

The way I see it, you can make the boat asymmetrical by blowing up one end or deflating it. Either way you do it, it is no longer the same hull, so comparisons are useless.


Quote:
The performance (used in a broad sense) of a boat is the sum of many factor. Some are detrimental to resistance and good for something else and vice versa. The end result is a boat that will please some people and inspire derision in others. What matters is if the paddler likes the boat and it does what he/she wants doing.


Amen to that, my friend. :wink:

Which reminds me....


After spending several days in the Adirondacks learning to spin short, tippy, well rockered, symmetrical canoes in circles, and just tooling around the water in general, I have come to the conclusion that I like these little boats a whole lot. They track fine once up to speed, needing just a hint of a J or a pitch or Canadian stroke, and they turn on a dime. If the wind blows you off course, a simple correction (if done in time) pops you right back where you belong. They will flat spin nicely or spin wildly when heeled to the rails.

Once under way, you can do a couple of cross forward strokes (very easy due to their narrow width) to get the stern to skid and then keep it skidding with just hard forward strokes on the onside to paddle an inside circle. A quick stern pry followed by a static bow draw and they turn well past 90º, even more if you carve the turn, so I guess they'd be great WW boats (that is if you want to take one of Tom's $5000 wood and canvas masterpieces down Class II) And yet, they are efficient feeling and fast paddling (sorry, I left the GPS in the car) boats for their length... fast enough for me, anyway.

The event came on the heels of the WCHA annual assembly, with many folks attending both, so there were several canoes there that were completely inappropriate for FreeStyle use (like Lady BK's "Nymph" and my "Scherzo"). Charlie Wilson and Tom MacKenzie gave us all a wonderful lecture on modern canoe design and history (and all the dirt as well), using the various "Boats on the Beach" to illustrate their points. Included in this menagerie was an Osprey.

Being a FreeStyle symposium, and the Osprey having its rocker primarily in the bow, it sat on the beach most of the time. But occasionally, one of the better paddlers took it out for a paddle. To my eyes, there was very little difference in what they were able to do with it compared with the specialized styling canoes. As always, paddler skill is 90% of the equation.

I wish I had tried the Osprey to give a duffer's point of view, but alas, it was time to leave before I knew it. But since we all know that JW designed this very well thought of solo boat, I'll leave you with this link to one of his articles to digest over several cups of coffee this weekend:

John Winters on Boat Design

:D

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PostPosted: July 24th, 2009, 7:52 pm 
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BK that is a real good article.

But I am pooped from AFS...so much paddling and yakking..God should have made 30 hour days to allow for sleep.

Your homework is that outer gimbal.. :wink: Mine is reading the link you supplied.


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PostPosted: July 25th, 2009, 7:01 am 
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BK wrote:


Quote:
Gut feelings combined with paddler subjectivity? Sounds like a recipe for disaster to me.


Uh... just kiddin'. :wink:


That's why I like to sneak that objectively derived performance prediction stuff in :D

Quote:
Minor quibble here. etc.


Actually a major quibble as I misread "knots" instead of "km/p/hr". :doh:

Mea Culpa and many apologies. Need to read more carefully or is the Alzheimers finally taking hold? Or should I sue the speed reading course people? :lol:

Quote:
That means we can improve the capacity of a symmetrical design by adding buoyancy aft and not affect the efficiency/speed of the hull at all? I can see nothing wrong with doing that, although I suspect that this will affect the water returning at the stern and, perhaps, increase turbulence?


That is what some have done on their versions of the Prospector (although I suspect that they did it more to make thermoforming easier for Royalex versions) Of course, you can also do it by filling out the waterlines just aft of the midpoint. Neither need increase the beam at the paddling station and, unless carried to extremes can reduce turbulence, reduce wetted surface and increase effective waterline length. Not sure "all" symmetrical boats would benefit from this treatment but many would. I am thinking of the wood/canvas boats that seem to develop hollow waterlines in the ends where the frames make an abrupt change from "U" to "V" sections. One has to treat all as individual cases trying to achieve a net improvement.

Quote:
The way I see it, you can make the boat asymmetrical by blowing up one end or deflating it. Either way you do it, it is no longer the same hull, so comparisons are useless.


Exactly. One hopes that you will get a different (improved?) boat when you change something. Otherwise, what's the point? The comparison that works is the comparison between the starting shape and the resulting shape. Designers have been doing this for years hopefully to the benefit of paddlers. For a good discussion on this methodical development of a hull shape see "Taylor's Speed and Power of Ships". One might even find Lackenby's original paper. He developed a neat program for altering prismatic coefficients and LCB's based on a generic hull shape. Wish I could tell you where to find them. Don't ask to borrow mine. I have had bad luck loaning out things

Quote:
Being a FreeStyle symposium, and the Osprey having its rocker primarily in the bow, it sat on the beach most of the time. But occasionally, one of the better paddlers took it out for a paddle. To my eyes, there was very little difference in what they were able to do with it compared with the specialized styling canoes. As always, paddler skill is 90% of the equation.


I will repeat for the umpteenth time. The Osprey is not nor was it ever intended to be a freestyle boat. BK is dead on when he talks about paddler skills. I used to have a video (loaned it and never got it back) of Pat Moore doing freestyle in a 17' Grumman using a shovel as a paddle. He did just fine to my eyes and I bet a lot of people could do as well.

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PostPosted: July 25th, 2009, 7:53 pm 
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Jwinters wrote:
That is what some have done on their versions of the Prospector (although I suspect that they did it more to make thermoforming easier for Royalex versions)


I've been told that the shape of the Swift Osprey is somewhat defined by Bill Swift's decision not to use a two piece mold. The design allows the boat to be "squirted" out of the end of the mold and thereby avoid mold separation artifact. Makes me wonder which is more accurate to your original drawings, the Swift version or the plans sold by Greenval. How much do they vary (if at all), or can't you can say without divulging too much proprietary info?

Quote:
Of course, you can also do it by filling out the waterlines just aft of the midpoint. Neither need increase the beam at the paddling station and, unless carried to extremes can reduce turbulence, reduce wetted surface and increase effective waterline length. Not sure "all" symmetrical boats would benefit from this treatment but many would. I am thinking of the wood/canvas boats that seem to develop hollow waterlines in the ends where the frames make an abrupt change from "U" to "V" sections. One has to treat all as individual cases trying to achieve a net improvement.


As always, John, you provide food for further thought. These are the very same types of changes I just mentioned on another thread:

Fastest Solo Canoe

Definitely an improvement for several reasons IMHO, but after staring at the church-like arches inside one of Tom MacKenzies' solo canoes for three days, I have to say I wish it weren't so.

Quote:
One might even find Lackenby's original paper. He developed a neat program for altering prismatic coefficients and LCB's based on a generic hull shape.


Isn't that what the computer design programs like BearBoatPro do as well?

Quote:
I used to have a video (loaned it and never got it back) of Pat Moore doing freestyle in a 17' Grumman using a shovel as a paddle. He did just fine to my eyes and I bet a lot of people could do as well.


At the AFS, Charlie Wilson said that was just a cheap trick, made possible by the use of a big, beamy canoe laid to the rails and a real long lever provided by a grave digger's shovel handle. He said that anyone can do it.

Anyone but me, that is. :doh: :lol:

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