"Michael Daly" wrote in message
...
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?
====================
Beause you've failed to make your case against the other sites I
have read.



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.
========================
No, you did not answer the question I asked. You snipped it out,
and ignored it. Why is that?



Mike

"rick" wrote in
ink.net:


"Michael Daly" wrote in message
...
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?
====================
Beause you've failed to make your case against the other sites I
have read.

Actually a very good case was made by posting information from a credible
source on sea kayak length.

Of the three sites you posted one was about Canoes from someone named Cliff
Jacobson. What are his credentials? The other two site specifically talk
about water line lenght, not overall length, a point that Mike has stressed
throughout this thread. The original poster asked for a speed comparison of
two kayaks of similar overall length, and Mike correctly pointed out that a
speed comparison can not be made based on overall length. In response you
post three sites, one about canoes and the other two which support Michaels
contentention that waterline length (not overall length) is an influencing
factor.




See also:
http://www.kayakforum.com/cgi-sys/cg...?The_Myth_Of_L
ength

No, I'm posting web sites that state the opposite of you, not
MY
opinion. Which of course you have snipped.

No, you posted two web sites which agreed with him.


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.
========================
No, you did not answer the question I asked. You snipped it out,
and ignored it. Why is that?

I read back through the thread and the only question you asked was related
to canoes, not sea kayaks, which is what the original poster was aksing
about. While Michael didn't answer the question directly (or maybe just
hasn't given the answer you want to hear) he did answer it by posting the
comparison of overall length vs water line length for 24 sea kayaks. I
don't think anyone is going to deny that a kayak with a 18' overall length
is going to have a longer waterline than a kayak with a 14' overal length
but the original poster was asking about two boats with that much of a
difference in overall length. The differences in overall length in the
boats that the OP was asking about was only about a foot and a half and it
is entirely possible that the boat with the longer overall length would have
a shorter waterline length, or at least be close enough that the water line
length would have a negligable impact in kayak speed. That's the point
that Michael has been making all along but you seem more interested in just
arguing by tossing out red herrings that are irrelevant to was the OP was
asking.

"John Fereira" wrote in message
.. .
"rick" wrote in
ink.net:


"Michael Daly" wrote in message
...
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?
====================
Beause you've failed to make your case against the other sites
I
have read.

Actually a very good case was made by posting information from
a credible
source on sea kayak length.

Of the three sites you posted one was about Canoes from someone
named Cliff
Jacobson. What are his credentials? The other two site
specifically talk
about water line lenght, not overall length, a point that Mike
has stressed
throughout this thread. The original poster asked for a speed
comparison of
two kayaks of similar overall length, and Mike correctly
pointed out that a
speed comparison can not be made based on overall length. In
response you
post three sites, one about canoes and the other two which
support Michaels
contentention that waterline length (not overall length) is an
influencing
factor.
=======================
I never claimed otherwise. He keeps asserting that overall
length is no indicator at all of waterline length. Most people
will recognise that typically the longer the boat, the longer the
waterline. In the discussion I was commenting on, he declared
length meant NOTHING to speed. He claimed 'many factors'
contribute to speed, but has yet to state what those are, even
after being asked. Again, I've never denied 'waterline' lenngth,
but going on about symantics doesn't prove anything.







See also:
http://www.kayakforum.com/cgi-sys/cg...?The_Myth_Of_L
ength

No, I'm posting web sites that state the opposite of you,
not
MY
opinion. Which of course you have snipped.

No, you posted two web sites which agreed with him.
=================
No, I don't think so. He claimed "many factors" affect speed,
but length wasn't one of them.





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.
========================
No, you did not answer the question I asked. You snipped it
out,
and ignored it. Why is that?

I read back through the thread and the only question you asked
was related
to canoes, not sea kayaks, which is what the original poster
was aksing
about.
==========================
Boats are boats. Being covered on top has no relation.



While Michael didn't answer the question directly (or maybe
just
hasn't given the answer you want to hear) he did answer it by
posting the
comparison of overall length vs water line length for 24 sea
kayaks.
=====================
No, he ignored, and snipped out the direct question I asked, and
repeating assertion about length does not answer the question I
asked, which was what are the 'many factors', since length plays
no part, in the speed of a boat.


I
don't think anyone is going to deny that a kayak with a 18'
overall length
is going to have a longer waterline than a kayak with a 14'
overal length
but the original poster was asking about two boats with that
much of a
difference in overall length.
=======================
Looks like Mike did. He claimed that overall length did not
correlate to waterline lenght.


The differences in overall length in the
boats that the OP was asking about was only about a foot and a
half and it
is entirely possible that the boat with the longer overall
length would have
a shorter waterline length, or at least be close enough that
the water line
length would have a negligable impact in kayak speed. That's
the point
that Michael has been making all along but you seem more
interested in just
arguing by tossing out red herrings that are irrelevant to was
the OP was
asking.
==========================
No, you seem to be selectivly reading what you want. I have
asked him what other factors are involved, he has refused to
answer, and continues his symantics about 'length'.

OK, I'll toss another question...

How much faster would be the Manitou (12'10" by 25") than the Drifter
(12'7" by 32.5")?

Tell me in percentage...

On 16-Jun-2005, "rick" wrote:

Beause you've failed to make your case against the other sites I
have read.

How about - the sites you identified are irrelevant to the discussion.
Just because they talk about waterline length means nothing in the
context of comparing waterline length and overall length.

No, you did not answer the question I asked. You snipped it out,
and ignored it. Why is that?

Probably because your line of questions is not contributing to the
discussion. You just want to nit-pik on trivia.

The _fact_ is that overall length is not a reasonable indicator
of kayak performance. Waterline length may be, other factors
being equal. If you can't deal with that, there's nothing I can
do about it.

Mike

On 16-Jun-2005, Peter wrote:

No, it clearly was never true. Even taking the subset of kayaks you
chose, you calculated a correlation coefficient of 0.79 indicating a
very high level of correlation.

Not high enough and nowhere near the level you claimed without any
proof.

The _fact_ is that at that level, the differences in overall length
between two kayaks are comparable to the differences in overall
length and waterline length in one kayak. Clearly a much higher
level of correlation is required than 0.79. In this case, the
mathematic definition of correlation has to take a back seat
to the more pragmatic need to produce information that is of
some value.


If all kayak types were included the
correlation would be even higher.

Your claim - how about something resembling proof? Your last
guess of 0.95 was based on nothing.

In the particular case of the two kayaks considered by the OP, their
lengths only differed by about 2' but the hull shapes appear to be quite
similar with no obvious difference in overhang. Therefore it's highly
likely that the Biscyne which is longer overall will also have a longer
waterline length.

Even if it does have a longer waterline length, that still does not
guarantee that the speed is higher. Hydrodynamics trumps simple
geometric parameters.

How about offering something of value instead of simply trying
to not-pick? Like offering some data that actually backs up you
ludicrous claim that what I am saying is false.

Mike

On 16-Jun-2005, "rick" wrote:

He claimed "many factors" affect speed,
but length wasn't one of them.

Where exactly have I ever said that waterline length doesn't
affect speed? I said that overall length is not a usable
indicator because of the great variation between overall
length and waterline length. I demonstrated that with
a scatter graph of the two parameters for _real_ sea kayaks.

Mike

Michael Daly wrote:
Like offering some data that actually backs up you
ludicrous claim that what I am saying is false.

You already provided it yourself. After first making the claim that
there was "no correlation" between LOA and LWL, you later provided data
indicating that the correlation was 0.79 which clearly showed your
initial statement to be false. QED.

On 16-Jun-2005, "rick" wrote:

I
don't think anyone is going to deny that a kayak with a 18'
overall length
is going to have a longer waterline than a kayak with a 14'
overal length
=======================
Looks like Mike did. He claimed that overall length did not
correlate to waterline lenght.

Lookee, Lookee what I found on the web site that someone posted
with Sea Kayaker magazine data:

Prijon*Calabria Current Design Andromeda
LOA 4.42m (14.5ft) 5.26m (17.25ft)
LWL 3.96m (13 ft) 4.19m (13.75ft)
Drag 16.7 lb 18.0 lb

So here we have two _real_ sea kayaks, one that is more than 17 foot
long and another that is over 14 feet long (one 19% longer) yet
their waterline lengths are 13 and 13.75 feet respectively (one
only 6% longer).

Note in particular that the _shorter_ kayak has less resistance
at 4.5 knots.

Is this what you call a high correlation between LOA and LWL? Does
this prove that long kayaks are faster?

Mike

"Michael Daly" wrote in message
...

On 16-Jun-2005, "rick" wrote:

He claimed "many factors" affect speed,
but length wasn't one of them.

Where exactly have I ever said that waterline length doesn't
affect speed? I said that overall length is not a usable
indicator because of the great variation between overall
length and waterline length. I demonstrated that with
a scatter graph of the two parameters for _real_ sea kayaks.

Mike
======================
OK Not getting anywhere I see. You still won't/can't answer the
question I asked. Thanks anyway. I'll just wait or somebody
else, someday...