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What do I lose by having a shorter boat?
Hi there!
I'm considering a Necky Manitou (12'10") for light weight, seat, looks and price, but I wonder, what would I lose in speed to, say, a Mainstream Biscayne (14'6")? I won't be going all out though, just keeping a medium pace for workout. Thanks! |
On 14-Jun-2005, "donquijote1954" wrote:
I'm considering a Necky Manitou (12'10") for light weight, seat, looks and price, but I wonder, what would I lose in speed to, say, a Mainstream Biscayne (14'6")? Impossible to say. There are many factors that affect speed and overall length isn't one of them. I won't be going all out though, just keeping a medium pace for workout. If all you want is a workout, it doesn't matter how fast the kayak is. One hour of paddling is one hour of paddling regardless of what you paddle. Mike |
"Michael Daly" wrote in message ... On 14-Jun-2005, "donquijote1954" wrote: I'm considering a Necky Manitou (12'10") for light weight, seat, looks and price, but I wonder, what would I lose in speed to, say, a Mainstream Biscayne (14'6")? Impossible to say. There are many factors that affect speed and overall length isn't one of them. ===================== That's not what I have always read. I've always thought that for boats with the same width and load, length is the determining factor on speed. http://gorp.away.com/gorp/publishers/ics/how_cano.htm http://www.evergreencanoe.com/canoe_design.html http://www.solarnavigator.net/hull_speed.htm I won't be going all out though, just keeping a medium pace for workout. If all you want is a workout, it doesn't matter how fast the kayak is. One hour of paddling is one hour of paddling regardless of what you paddle. Mike |
That's what I read too. The question is how a recreational boat would
be slower than a touring boat of the same lenght. I read a bottom that makes for more initial stability also produces less speed. For example the Biscayne at 14'6" was rated a mere 3 out of 5 in speed when it was a Dagger Savannah... http://www.dagger.com/product.asp?Bo...C&BoatI D=135 Yet it's rated as fast by several reviewers... "Just bought a Savannah Expedition model. Love it -- fast, stable, tracks beautifully. Great fit for me. Paddle some rivers, some lakes, some of Great Lakes. When I demo'd 5 other boats the Savannah was the hands-down winner." http://www.paddling.net/Reviews/show....html?prod=483 |
If it's a work out you want Mike is spot on.
As a rule of thumb , longer boats witgh the same displacement are generally faster. There are exceptions always. You may be swapping speed and tracking fonr initial stability. For scooting about a pond and a work out I am not sure it matters. Alex |
"Michael Daly" wrote in message ... Impossible to say. There are many factors that affect speed and _overall_length_ isn't one of them. On 14-Jun-2005, "rick" wrote: That's not what I have always read. I've always thought that for boats with the same width and load, length is the determining factor on speed. Better read more carefully. Overall length is not a determining factor. Waterline length is _one_ factor. In kayaks, there is _no_ correlation between overall length and waterline length. Mike |
On 14-Jun-2005, "donquijote1954" wrote: I read a bottom that makes for more initial stability also produces less speed. Take the book you read that in and toss it. There are a lot of misconceptions in canoeing and kayaking. Most seem to have to do with speed. You can't predict speed by looking at one geometric factor in a hull. Speed is a function of many factors. Mike |
Michael Daly wrote
[...] Take the book you read that in and toss it. There are a lot of misconceptions in canoeing and kayaking. If I did that with all my canoeing books, most of those should be thrown away :-) But I admit that it really amazes me how most modern canoe books still repeat the same nonsense over and over an again. While there is so much really good information available. I understand there is a need to simplify in books, but it could be done a lot better IMNHO. |
"Michael Daly" wrote in message ... "Michael Daly" wrote in message ... Impossible to say. There are many factors that affect speed and _overall_length_ isn't one of them. On 14-Jun-2005, "rick" wrote: That's not what I have always read. I've always thought that for boats with the same width and load, length is the determining factor on speed. Better read more carefully. Overall length is not a determining factor. Waterline length is _one_ factor. In kayaks, there is _no_ correlation between overall length and waterline length. ======================= Now you're just trying to over your statement. What kind of canoe do you have that the waterline length isn't inreased when the "overall" length is inceased? I responded only to your statemenet that length HAS NO effect on speed. That dosn't appear to be true. If length plays no factor, then explain all these other "many factors" that do. Mike |
I know where Mike is coming from and it is splitting hairs. The
Eddyline Night Hawk for example drops fron the bow to the water line very quickly and the stern is rather abrupt too. This makes it faster than the over all length would indicate . The Old Chinook is a little faster than most would think because of the same design feature. Most boats have however a gracefull drop into and exit from the water sometimes 2 feet from the tip if the bow. An old Seaward Quest is a case in point. That said the Quest is a rocket. Water line length has a large effect on speed, other design charictaristics do as well. Sealution from Teiken / Wildernes Systems for example is long but broad at the centre line. This boat enters the water at the bow cutting nicely then fattens up like a barge a few feet back giving in effect a second bow wave in stead of gently parting and uniformly pushing the water out of her way. The lines to the stern cause a drag that slows the boat down more as they are abrupt and don't allow a smooth flow . They are a great beginner boat but these are design realities.. The bow also overhang the water line by about 16 inches at least. The boats I preffer are not the fastest on the water but rather the more gracefull. NDK Explored and Capella. Not that fast but nice boats. Some boats break these simple rules because they can plane and get the known water lines right up out od the way. This you will se if you surf with WW boats. There is all kinds of cool math on this but most of it is common sense and theoretical math can be blown away because rules are narrow and often just accepted theorys. Normally an 18 foot long touring kayak will be much faster than a 14 foot boat. I have a friend in a 14' 6" boat that I van hardly keep up with in my Explorer: But she is a bit of a race horse. Allow another variable here. I cary 20 or 30 pounds of safety gear for out trips, She carries a bottle of water and weighs 125 lbs. The boat displaces less water and as it is short has little or no rocker. Again variables. Anything you put on the water will be fun. If you want to paddle with Linda though , best trade the Lendal for a Honda. Alex |
On 15-Jun-2005, "rick" wrote:
What kind of canoe do you have that the waterline length isn't inreased when the "overall" length is inceased? He's asking about kayaks. As I said, there is no correlation between overall length and waterline length in kayaks. I responded only to your statemenet that length HAS NO effect on speed. I never said it had no effect on speed. I said the effect cannot be determined by knowing overall length. If you have waterline length and you are comparing _very_similar_ hulls, you could make some estimation of expected speeds. Mike |
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Michael Daly wrote: I never said it had no effect on speed. I said the effect cannot be determined by knowing overall length. If you have waterline length and you are comparing _very_similar_ hulls, you could make some estimation of expected speeds. Mike They got similar overhang, but another question that intrigues me is how the depth of the V affects speed, ie. how a recreational boat would be slower than a touring boat of the same lenght. I read, for example, that the Old Town T-160 is "slow" at 16' because of a shallow V bottom. |
At the risk of getting too technical, can we list 5-10 key factors
effecting kayak speed? Then, can we go the next step, and ask, roughly, which of these factors have the greatest impact on speed (perhaps a rule-of-thumb weighted ranking)? I'm new to this, and thus far, the discussion has been interesting. |
On 15-Jun-2005, "donquijote1954" wrote: They got similar overhang, but another question that intrigues me is how the depth of the V affects speed, ie. how a recreational boat would be slower than a touring boat of the same lenght. I read, for example, that the Old Town T-160 is "slow" at 16' because of a shallow V bottom. Again, this can't be known based solely on a vague description of one property. As far as a shallow V bottom making a kayak slow - one of the sea kayaks with the least resistance (Superior Kayaks Hawk) has a shallow V hull and hard chines - both of which are claimed by various people to make kayaks slow. Mike |
"Michael Daly" wrote in message ... On 15-Jun-2005, "rick" wrote: What kind of canoe do you have that the waterline length isn't inreased when the "overall" length is inceased? He's asking about kayaks. As I said, there is no correlation between overall length and waterline length in kayaks. =============== So, you're saying a 12' kayak has a waterline length the same as a 16' kayak? I responded only to your statemenet that length HAS NO effect on speed. I never said it had no effect on speed. I said the effect cannot be determined by knowing overall length. If you have waterline length and you are comparing _very_similar_ hulls, you could make some estimation of expected speeds. ============== I saw a statement that said length has NO bearing on speed. I still see that as incorrect. Mike |
"BCITORGB" wrote in message oups.com... At the risk of getting too technical, can we list 5-10 key factors effecting kayak speed? Then, can we go the next step, and ask, roughly, which of these factors have the greatest impact on speed (perhaps a rule-of-thumb weighted ranking)? =============== I asked him that. He snipped out the question. I'm new to this, and thus far, the discussion has been interesting. ============== The speed thing has been discussed but nobody has ever explained it very well... The web sites I posted seemed ok, but they don't specifically talk about kayaks. Never paddled one, but I can't imagine that their design in the hull is that dis-similar from other boats. |
"Michael Daly" wrote in message ... On 15-Jun-2005, "rick" wrote: As I said, there is no correlation between overall length and waterline length in kayaks. Mike I am sorry this is just drivel dressed up as an authoritative opinion. Of course there is a correlation between overall length and waterline length in kayaks. If you took the overall length and the waterline length of all kayaks, say, reviewed in www.paddling.net these values would correlate highly significantly. You should precede your NG postings with a disclaimer 'I have no real appreciation of scientific concepts'. VD |
On 15-Jun-2005, "Van D" wrote: If you took the overall length and the waterline length of all kayaks, say, reviewed in www.paddling.net these values would correlate highly significantly. I looked at that web site and couldn't find any such data. Overall lengths were stated, but not waterline lengths. You should precede your NG postings with a disclaimer 'I have no real appreciation of scientific concepts'. So you are suggesting that all kayaks have the same shaped bow and stern? If you actually look at kayaks, you'll see that that is not true. Mike |
On 15-Jun-2005, "rick" wrote: He's asking about kayaks. As I said, there is no correlation between overall length and waterline length in kayaks. =============== So, you're saying a 12' kayak has a waterline length the same as a 16' kayak? ??? You can't read very well, can you? I never said it had no effect on speed. I said the effect cannot be determined by knowing overall length. If you have waterline length and you are comparing _very_similar_ hulls, you could make some estimation of expected speeds. ============== I saw a statement that said length has NO bearing on speed. I still see that as incorrect. I can't comment on what you think you see. I didn't write any such thing. Take a look at this graph: http://www.greatlakeskayaker.ca/LengthVsResistance.htm It shows the resistance a kayak generates at a speed of 4.5 knots versus the overall length for a range of lengths from 5.14m to 5.24m. This data is taken from Sea Kayaker magazine reviews. As you can see, the data is all over the place. The variation in length is less than 2% but the variation in resistance is over 13%. The line on the graph is a trendline (linear regression) and is showing that there is, according to this data, an _increase_ in resistance with length. You folks are claiming the opposite. While you may wave you hands in the air and make claims based on misconceptions, I am making statements based on what is found in real kayaks being sold to real people in the real world. Mike |
Michael Daly wrote:
On 15-Jun-2005, "Van D" wrote: If you took the overall length and the waterline length of all kayaks, say, reviewed in www.paddling.net these values would correlate highly significantly. I looked at that web site and couldn't find any such data. Overall lengths were stated, but not waterline lengths. You should precede your NG postings with a disclaimer 'I have no real appreciation of scientific concepts'. So you are suggesting that all kayaks have the same shaped bow and stern? If you actually look at kayaks, you'll see that that is not true. No, he's suggesting that you're using the term "correlation" incorrectly. When two variables are correlated it means that they have a tendency to vary in the same manner, not that there is a one-to-one correspondence in each particular case. So human height and weight are two variables with a highly positive correlation. In general people who are taller tend to be heavier although there are certainly many cases of a particular individual being taller than someone else who is heavier. Similarly kayaks with a long overall length have a tendency to also have a long waterline length. |
Speed and waterline and blah, blah ,blah is whats in the catalog, period. I
started paddling a Necky Santa Cruz 12" boat 3 years ago. Now at 53 I have switched to a lightening fast Necky Zoar. Is it as fast as a 17' 21 wide kevlar boat? On paper NO. I my hands its faster because I'd spend most of the time upsidedown in the kevlar boat. Speed is relative to the person paddling and what they like and are comfortable with. If you want a 13 or 14' boat and it suits your needs, who cares how *fast* it is. One of you young sprouts got probably paddle a Pungo faster then I can paddle anything. But I like my boat best. I think you should get the Necky mainly because we have 5 of them and we like them a lot, personal preference. Works for me. Bub "donquijote1954" wrote in message ups.com... Hi there! I'm considering a Necky Manitou (12'10") for light weight, seat, looks and price, but I wonder, what would I lose in speed to, say, a Mainstream Biscayne (14'6")? I won't be going all out though, just keeping a medium pace for workout. Thanks! |
"Michael Daly" wrote in message ... On 15-Jun-2005, "rick" wrote: He's asking about kayaks. As I said, there is no correlation between overall length and waterline length in kayaks. =============== So, you're saying a 12' kayak has a waterline length the same as a 16' kayak? ??? You can't read very well, can you? =============== Very well. You seem to snip what you can't answer. I never said it had no effect on speed. I said the effect cannot be determined by knowing overall length. If you have waterline length and you are comparing _very_similar_ hulls, you could make some estimation of expected speeds. ============== I saw a statement that said length has NO bearing on speed. I still see that as incorrect. I can't comment on what you think you see. I didn't write any such thing. ================= Only with wiggling about the definition of is, eh? Again, how does a longer kayak "overall" not have a longer waterline for the same type hull? Take a look at this graph: http://www.greatlakeskayaker.ca/LengthVsResistance.htm ================== Your own web site? It shows the resistance a kayak generates at a speed of 4.5 knots versus the overall length for a range of lengths from 5.14m to 5.24m. This data is taken from Sea Kayaker magazine reviews. As you can see, the data is all over the place. The variation in length is less than 2% but the variation in resistance is over 13%. The line on the graph is a trendline (linear regression) and is showing that there is, according to this data, an _increase_ in resistance with length. You folks are claiming the opposite. ================= And you have yet to provide those many other factors. No one claimed that nothing but length affected speed. But for a given hull design, it still looks to me that that will be the major factor according to the sites I posted. While you may wave you hands in the air and make claims based on misconceptions, I am making statements based on what is found in real kayaks being sold to real people in the real world. =============== No, I'm posting web sites that state the opposite of you, not MY opinion. Which of course you have snipped. Guess you didn't read them. I was seriously asking for data. You have yet to provide that, or answer the questions I asked. Mike |
Bub wrote: Speed and waterline and blah, blah ,blah is whats in the catalog, period. I started paddling a Necky Santa Cruz 12" boat 3 years ago. Now at 53 I have switched to a lightening fast Necky Zoar. Is it as fast as a 17' 21 wide kevlar boat? On paper NO. I my hands its faster because I'd spend most of the time upsidedown in the kevlar boat. Speed is relative to the person paddling and what they like and are comfortable with. If you want a 13 or 14' boat and it suits your needs, who cares how *fast* it is. One of you young sprouts got probably paddle a Pungo faster then I can paddle anything. But I like my boat best. I think you should get the Necky mainly because we have 5 of them and we like them a lot, personal preference. Works for me. Bub Thanks! The Necky Zoar is another option... |
OK, here I found some interesting comparison regarding speed...
"The speed I get from the Manitou is also good. Since I can't accurately factor for wind, current and waves, all I can do is give my honest opinion/comparison which is that at my average cruising/daypaddling speed of 3.2-3.8 mph, the effort is no different between the Manitou and the QCC. The manitou starts to need a bit more effort at my workout pace which is around 3.8-4.5. After around 4.5 mph the bow seems to plunge a bit. I never could quite get 5 mph to show on the GPS, but then I don't plan to race it, I just wanted to see if the manitou could keep up, and I think it does. For day paddling purposes, the Manitou performance, stability, and comfort is a 10." The QCC I believe are full size kayaks so go and figure. |
Take a long look at the necky Zoar Sport. 14 foot boat w/rudder well made
and stable. A little more boat then the Manitou. At $999 w/rudder, its not bad. Bub "donquijote1954" wrote in message oups.com... Bub wrote: Speed and waterline and blah, blah ,blah is whats in the catalog, period. I started paddling a Necky Santa Cruz 12" boat 3 years ago. Now at 53 I have switched to a lightening fast Necky Zoar. Is it as fast as a 17' 21 wide kevlar boat? On paper NO. I my hands its faster because I'd spend most of the time upsidedown in the kevlar boat. Speed is relative to the person paddling and what they like and are comfortable with. If you want a 13 or 14' boat and it suits your needs, who cares how *fast* it is. One of you young sprouts got probably paddle a Pungo faster then I can paddle anything. But I like my boat best. I think you should get the Necky mainly because we have 5 of them and we like them a lot, personal preference. Works for me. Bub Thanks! The Necky Zoar is another option... |
Whatever you decide on read the reveiws at www.paddling.net and see what
owners have to say. Bub "donquijote1954" wrote in message oups.com... Bub wrote: Speed and waterline and blah, blah ,blah is whats in the catalog, period. I started paddling a Necky Santa Cruz 12" boat 3 years ago. Now at 53 I have switched to a lightening fast Necky Zoar. Is it as fast as a 17' 21 wide kevlar boat? On paper NO. I my hands its faster because I'd spend most of the time upsidedown in the kevlar boat. Speed is relative to the person paddling and what they like and are comfortable with. If you want a 13 or 14' boat and it suits your needs, who cares how *fast* it is. One of you young sprouts got probably paddle a Pungo faster then I can paddle anything. But I like my boat best. I think you should get the Necky mainly because we have 5 of them and we like them a lot, personal preference. Works for me. Bub Thanks! The Necky Zoar is another option... |
And let's not forget these two pages...
http://www.unold.dk/paddling/article...kvelocity.html http://www.unold.dk/paddling/article...tatistics.html Mike Soja |
"Bub" wrote in message news:LUdse.19405$gL4.18313@trnddc07... Take a long look at the necky Zoar Sport. 14 foot boat w/rudder well made and stable. A little more boat then the Manitou. At $999 w/rudder, its not bad. Bub It is a bit of a bathtub though :-) "donquijote1954" wrote in message oups.com... Bub wrote: Speed and waterline and blah, blah ,blah is whats in the catalog, period. I started paddling a Necky Santa Cruz 12" boat 3 years ago. Now at 53 I have switched to a lightening fast Necky Zoar. Is it as fast as a 17' 21 wide kevlar boat? On paper NO. I my hands its faster because I'd spend most of the time upsidedown in the kevlar boat. Speed is relative to the person paddling and what they like and are comfortable with. If you want a 13 or 14' boat and it suits your needs, who cares how *fast* it is. One of you young sprouts got probably paddle a Pungo faster then I can paddle anything. But I like my boat best. I think you should get the Necky mainly because we have 5 of them and we like them a lot, personal preference. Works for me. Bub Thanks! The Necky Zoar is another option... |
On 15-Jun-2005, Peter wrote:
When two variables are correlated it means that they have a tendency to vary in the same manner, not that there is a one-to-one correspondence in each particular case. Fine - I'm using the term correctly. When you compare kayaks, you will see that some have overhanging stem and/or stern, others have plumb stem and/or stern while others still have raked ends. Thus, you can find kayaks of the same overall length with very different waterline lengths. It is not automatically true that if a kayak has a longer overall length it necessarily has a longer waterline length. This is especially true when comparing kayaks of roughly the same length. That is why you cannot use overall length as a determining factor in estimating speed or resistance - only waterline length plays any role. What is so hard to understand in that? Mike |
Bub wrote: Take a long look at the necky Zoar Sport. 14 foot boat w/rudder well made and stable. A little more boat then the Manitou. At $999 w/rudder, its not bad. Bub Thanks! Two questions: Can the padding be removed from the seat? and, Do you get to use the rudder/keg or is it a nuisance? I'll quote something... 'The Zoar Sport is a brilliant little boat. At 14' it is a touring boat rather than a true sea kayak but I have found with mine that: 1) it handles very well on fla****er, keeping close to the longer, "faster" boats; 2) it handles extremely well in surf (force five conditions); 3) it is solid and durable; and above all 4) it is a comfortable fit (I am 6'4" 240 lbs). Great boat.' |
On 15-Jun-2005, "rick" wrote:
Again, how does a longer kayak "overall" not have a longer waterline for the same type hull The original poster said nothing about "same type hulls." He provided two overall lengths and asked for an assessment of how the speed would compare. I correctly stated that one cannot determine that from the information on overall length. But for a given hull design, it still looks to me that that will be the major factor according to the sites I posted. You're ignoring the data on the graph. The data comes from Sea Kayaker magazine and clearly shows that there is no correlation between overall length and resistance. Why do you keep insisting that there is? See also: http://www.kayakforum.com/cgi-sys/cgiwrap/guille/wiki.pl?The_Myth_Of_Length No, I'm posting web sites that state the opposite of you, not MY opinion. Which of course you have snipped. Try reading a book on the hydrodynamics of hulls. C.A. Marchaj's "Sailing Theory and Practice" is a good one. You can also stop assuming that overall length and waterline length are interchangable. I was seriously asking for data. I gave you some. It shows that there is no correlation between resistance and length for 24 common sea kayaks that have been reviewed in Sea Kayaker magazine. Mike |
Michael Daly wrote:
On 15-Jun-2005, Peter wrote: When two variables are correlated it means that they have a tendency to vary in the same manner, not that there is a one-to-one correspondence in each particular case. Fine - I'm using the term correctly. No, you're not. What you said before was "there is no correlation between overall length and waterline length in kayaks." If that were true it would mean that knowing the overall length would not give us any hint about the waterline length - that is it would be similar to my telling you my astrological sign and asking you to guess my weight. But in fact the overall and waterline lengths of boats are quite highly correlated and boats that are 18' long overall will almost always have waterline lengths greater than boats that are 14' long. The correlation isn't perfect (correlation coefficient of 1.0), but it is very high (correlation coefficient is probably around 0.95). An example graph of skin fold thickness vs. body fat, two highly correlated variables, is shown at: http://www.sportsci.org/resource/stats/correl.html In this case the correlation coefficient is 0.9 indicating a high degree of correlation, but you'll notice that there's quite a bit of scatter; i.e. there are many examples of specific individuals who may have a greater skin fold thickness than someone else while having a lower body fat percentage. In the same way, there would be some scatter if we plotted kayak overall lengths vs. their waterline lengths, but we'd clearly see that the *tendency* is for the longer boats overall to also have long waterline lengths. When you compare kayaks, you will see that some have overhanging stem and/or stern, others have plumb stem and/or stern while others still have raked ends. Thus, you can find kayaks of the same overall length with very different waterline lengths. It is not automatically true that if a kayak has a longer overall length it necessarily has a longer waterline length. And of course no one has ever argued otherwise - you're just rambling on debating strawmen. If you're going to use the term "correlation" then it would be good if you knew what it meant. |
On 15-Jun-2005, "Van D" wrote:
As I said, there is no correlation between overall length and waterline length in kayaks. Mike I am sorry this is just drivel dressed up as an authoritative opinion. Further info from the Sea Kayaker reviews. This shows the how much shorter the waterline length is than the overall length for bunch of real sea kayaks. Bergans Ally Folding 3.1% Nelo*FW*2000 3.2% Epic*Endurance*18 3.3% Prijon*Barracuda 5.3% KajakSport*Viviane 8.3% Prijon*Calabria 9.3% KajakSport*Viking*Ex. 9.4% Point65N*K1 VR 9.4% Seda*Glider 9.6% Feathercraft K-1 Exp. 9.8% Point65N*K1 R 12.2% VCP Aquanaut 13.6% VCP Avocet 14.2% KajakSport*Artisan Mill. 14.9% PH Quest 16.2% PH Bahiya 16.5% Nordkapp*H2O 17.2% Current*Design*Andromeda 19.0% That's a pretty wide spectrum - from 3% to 19%. Correlation? I don't think so. Mike |
Waterline in fla****er, because in rough water the picture changes...
Michael Daly wrote: On 15-Jun-2005, "Van D" wrote: As I said, there is no correlation between overall length and waterline length in kayaks. Mike I am sorry this is just drivel dressed up as an authoritative opinion. Further info from the Sea Kayaker reviews. This shows the how much shorter the waterline length is than the overall length for bunch of real sea kayaks. Bergans Ally Folding 3.1% Nelo FW 2000 3.2% Epic Endurance 18 3.3% Prijon Barracuda 5.3% KajakSport Viviane 8.3% Prijon Calabria 9.3% KajakSport Viking Ex. 9.4% Point65N K1 VR 9.4% Seda Glider 9.6% Feathercraft K-1 Exp. 9.8% Point65N K1 R 12.2% VCP Aquanaut 13.6% VCP Avocet 14.2% KajakSport Artisan Mill. 14.9% PH Quest 16.2% PH Bahiya 16.5% Nordkapp H2O 17.2% Current Design Andromeda 19.0% That's a pretty wide spectrum - from 3% to 19%. Correlation? I don't think so. Mike |
Keenan & Julie wrote: "Bub" wrote in message news:LUdse.19405$gL4.18313@trnddc07... Take a long look at the necky Zoar Sport. 14 foot boat w/rudder well made and stable. A little more boat then the Manitou. At $999 w/rudder, its not bad. Bub It is a bit of a bathtub though :-) Don't pay attention. It's only envy... ;) |
On 16-Jun-2005, Peter wrote: boats that are 18' long overall will almost always have waterline lengths greater than boats that are 14' Fine, but we were comparing kayaks that were only a foot and a half or so different in length. Of the 105 kayaks on the web page of Sea Kayaker data, the average length is 5.2m (17 ft) with a standard deviation of 41cm (16 in). 78% of the kayaks fall within one standard deviation of the mean length. We're not talking about huge differences in length typically, especially since the standard deviation is comparable to the differences in LOA and LWL. but it is very high (correlation coefficient is probably around 0.95). Instead of pulling these numbers out of your ass, how about some facts? Based on the data I posted on 18 kayaks (showing percent differences in LWL and LOA), the actual correlation coefficient is 0.79. Not exactly tight. In terms of performance, that is a significant difference. Thus it is not reasonable to make sweeping statements that one can predict performance based on LOA instead of LWL. You guys are pulling out extreme examples based on hand-waving about theories that few of you actually understand. I'm talking about real kayaks in the real world. In the real world, we can't reduce performance estimates on vague physical characteristics. Mike |
On 16-Jun-2005, "donquijote1954" wrote:
Waterline in fla****er, because in rough water the picture changes... I'm talking about defined LWL. Mike |
Michael Daly wrote:
On 16-Jun-2005, Peter wrote: boats that are 18' long overall will almost always have waterline lengths greater than boats that are 14' Fine, but we were comparing kayaks that were only a foot and a half or so different in length. Your previous statement: "there is no correlation between overall length and waterline length in kayaks" made no such distinction that it only applied to some set of kayaks that all had about the same length, nor was it limited to sea kayaks. Of the 105 kayaks on the web page of Sea Kayaker data, the average length is 5.2m (17 ft) with a standard deviation of 41cm (16 in). 78% of the kayaks fall within one standard deviation of the mean length. We're not talking about huge differences in length typically, especially since the standard deviation is comparable to the differences in LOA and LWL. but it is very high (correlation coefficient is probably around 0.95). Instead of pulling these numbers out of your ass, how about some facts? Based on the data I posted on 18 kayaks (showing percent differences in LWL and LOA), the actual correlation coefficient is 0.79. Naturally the correlation coefficient will be less if you restrict the kayaks under consideration to ones with fairly similar lengths (all but one in the range from 16' to 19'). In a more complete list with play boats, WW boats, surfskis, etc. also included the coefficient would be much higher. Since your original statement just referred to the general category "kayaks" my estimate was based on this broader selection. However, a correlation coefficient of 0.79 is a far cry from your original claim that there is "no correlation" which would imply a correlation coefficient of 0. The numbers in this case are much closer to perfect correlation than they are to no correlation. In the reference to statistical terms I cited earlier, any correlation coefficient of 0.5 or higher is regarded as "high" (0.1 - 0.3 is small, 0.3 - 0.5 is moderate) and greater than 0.7 is "very high." Not exactly tight. Even taking your specified subset of kayaks, the correlation is "very high" rather than your original statement that it is nonexistent. |
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So, like, shorter boats are slower eh? Sheesh, how do you guys decide what to order for lunch? Must take hours. |
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