John Fereira ) writes:

Both CLC and Pygmy offer a line of designs that one can build either from
computer cut panels or from a set of plans and cut the panels according to

I didn't claim either company sold custom plans or kits. I only wrote that
it's possible to do cheaply becuase all that has to be done is to change a
few numbers in the design program and the computer cuts out the new boat
panels or station mould patterns. Plywood and stripper kayaks could be
custom made just like you buy a custom tailored business suit, but at
minimal extra cost.

Even for the standard models, while the plans + materials or a kit costs
less than a similarly designed composite boat, when one adds in the cost of
tools necessary to build it, extras like varnish, and the cost of labor, I'm
not sure that in the end one will save "a lot of money".

you save approx 1/3 off the cost of a stripper boat by building yourself.
that's why so many people do it. that's why Ted Moores is so popular.

For many, the most efficient hull for flat out forward speed performance
might not be desirable.

please show me where I claimed speed vs horsepower was the sole reason for
choosing a kayak. I do think speed is the principle reason people choose
kayaks over other boats like canoes and punts and for that reason I think
buyers should be presented with the information on how fast their kayak is
designed to go with different levels of effort.

If paddlers were only concerned about paddling at a high speed for long
distances you might have a point, but paddling is much more than that.

the point of this discussion about hull resistance and horsepower
requirement is how much more effort a person has to exert to keep up with
a group of paddlers. I don't know about paddling at high speed, just the
speed the gropup is paddling at. If you don't want to be exhausted at the
end of a day of paddling in a group then the power you have to put out to
maintain the group speed is the most important factor.

While there are some that will buy a kayak based on the stats or brochure
(and the appearance of the boat), pretty much every paddler with experience
will recommend that one actually sit in a paddle a boat before buying it.
It doesn't take a brochure to tell me that a boat is too small if the
cockpit is so tight that it cuts off circulation to my legs.

sadly, yes, that's how it is done now. but it doesn't have to be done that
way. last summer I was told by a couple of kayak fanatics in this very
newsgroup that it was wrong to choose a kayak based on how it felt and
that after one or two seasons such people are eager to buy the kayak they
should have bought in the first place. if sellers provided the design
range for paddler weight and dimensions potential buyers could quickly
narrow down the kayaks to the ones most suitable and they could choose
from among those kayaks. you may be aware of how igorant kayak sales staff
are. they are happy just to sell the kayak and cannot provide much in the
way of help to the buyer. buyers would be better off with relevant design
information.

That question is typically asked by people that have very little experience
in kayaks, and is often accompanied with little addtional data that would
help answer the question. I've answered the question many times, and
usually recommended several models with the suggestion to try as many as
possible and decide for themselves what kayak is right for them.

how many kayak buyers do you think are people with "very little experience
in kayks"? 80%? 90%? 95% people do generally know what they weigh and how
tall they are. people can take their own body measurements just like
people who buy skis and bicycles do. there are people who lurk in this
newsgroup who will say that telling people who have very littel expericne
to try kayaks for themselves in not good adivce. I tend to agree compared
to what they could do with more design information.

Kayaks and canoes cost more than bikes, skis,
and skateboards.


I don't know what a skateboard costs but it's certainly possible to spend
more a bicycle or snow skis than on a kayak.


if its possible it's out at the exteme end of the price range. compare
averages instead.

Here's an analogy. I chose my last two new automobiles by doing reasearch
at the public library and then went out and bought them. I've been driving
the most recent one for 15 years hope to keep driving it for years to
come. I understand that people buying automobiles today have even more
information available off the Interent than I had. However buying a new
automobile by going a dealership for a test drive is the worst possible
way of buyiung a new automobile that I can think of. Kayaks don't have the
volume and interest of automobiles but a better job can be done at no
extra cost providing relevant information for kayak buyers, information
which is paddler-oriented rather than boat oriented. Kayak sellers would
better serve their customers by concentrating more on the paddler and less
on the boat. that's why I suggest making power requriements, body weight,
and body size design information available to buyers. I'd certainly
provide horsepower rather than total hull resistance.


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On 1-Jun-2004, (William R. Watt) wrote:

The remaining kayak, Sonoma, is
the slowest. Its length is unknown. There is an error in the data
for the Sonoma at the fastest speed, revealed by a sudden change
in its graph.

The Sonoma is 13.5 ft long. It does appear that the data is suspect
at the top end.

Mike

On 1-Jun-2004, (William R. Watt) wrote:

wait just a darned minute, are you saying the data you presented is not
test data but is calculated from dimensions using Winter's KAPER model?
that's not data. sorry, it doesn't count as data.

No one does tank testing of kayaks. Too expensive. All data published
in Sea Kayaker is based on both KAPER and Taylor. Both produce similar
results. These calculations have been calibrated with real test data.

If you want better data, you'll look long and hard.

Mike

On 2-Jun-2004, (William R. Watt) wrote:

BTW, the following figure shows what I explained in a previous post
but which you claimed was not correct.

http://www.greenval.com/fig3_1.gif

I've seen it. I'm familiar with it. It does not.

in your previous post you claimed minimal total hull resistance occurs

What I was referring to was my statement that friction resistance increases
with length and wave resistance decreases with length.

Mike

martins wrote:

Hi Brian
you forgot about the seat thing. After the sales talk ends, the final
purchase many times is determined (for the first time buyer) by the way the
seat fits. I see tons of boats bought and sold , not so much by the way they
handle, as by the way the seat fits. Seems like only a small amount of
people will plunk down their money, take the boat home, rip out an
uncomfortable seat and replace it with something that works for them (then
drill a hole for the bilge water exit fitting/ mount a foot pump or a C50 or
an electric of some sort such as a waterbuster)

best wishes
Roy

Sad but true. Even sadder is the fact that many people buy boats based
on the PERCEPTION of comfort of the seat. The more it looks and feels
like an easy chair, the better they like it, not knowing that it's going
to be uncomfortable when paddling.

Michael Daly wrote:

On 1-Jun-2004, (William R. Watt) wrote:


wait just a darned minute, are you saying the data you presented is not
test data but is calculated from dimensions using Winter's KAPER model?
that's not data. sorry, it doesn't count as data.


No one does tank testing of kayaks. Too expensive. All data published
in Sea Kayaker is based on both KAPER and Taylor. Both produce similar
results. These calculations have been calibrated with real test data.

If you want better data, you'll look long and hard.

Better yet, do it yourself if you think it's so important.

William R. Watt wrote:

Brian Nystrom ) writes:


It would cost no more to custom design a plywood kayak built with
computer cut panels than to design a mass produced plywood kayak
built with computer cut panels.

How do you figure that?

companies like Chesapeke(?) Light Craft and Pygmy Boats sell plywood boats
and kits make from computer cut panels. people buy the boats or they
can assemble the kits themselves and save a lot of money.

Compared to what? When you factor in all the tools and other supplies,
plus the time involved, there is no savings at all. Building boats is a
labor of love, not an economic expedient.

More importantly, what percentage of kayakers build their own boats? For
that matter, what percentage is even capable of it or has a place to do
it? You seem to forget that we live in a country where most people can't
even change the oil in their cars, let alone build kayaks.

While it's certainly possible to custom design and cut panels for stitch
and glue boats, no one does so. The closest thing to it is Newfound
Woodworks will take a customer's design and make the panels for them,
but there are even fewer people who can design a boat than there are
than can build them.

... The most efficient hulls (least wetted surface
for a given displacement) are rounded in shape, which cannot be built
from flat panels. The cost to produce a mold for a one-off design is
prohibitive. One could have a boat custom designed and strip built, but
how many people are going to pay in excess of $5000 for a kayak?

yes, avoiding moulds for building resin boats one off was my point.
you can custom design and build a plywood or a "stripper" boat cheaper.

No kidding, but it's even more complex and time consuming to build one
than it is to do a S&G. BTW, I do build skin-on-frame boats, so I have
an idea what's involved.

as for the preformance of flat panel (hard chine) hulls its actually the
turbulence at the chines which creates more drag at higher speeds compared
to smooth chined hulls. the wetted surface vs wave-making again.

While turbulence is certainly a possibility with a poor design, it's not
a given. The wetted surface area is what makes the difference. Why do
you think that EVERY racing boat made has a rounded hull? Read the
manufacturer's literatue and read basic information on boat design and
they all say the same thing: round hulls have less surface area for a
given displacement than hard chine hulls. A spherical hull would have
the absolute least wetted area, but obviously, it would no longer be a
kayak or canoe.

some places you read about wetted surface vs wave-making. other places
its wetted surface vs residual resistance, where residual resistance is
any kind of drag that's not surface friction and includes drag due to
wave-making, poor tracking, hard chines, etc.

That's not the point, you can have two boats with the same wavemaking
resistance and one with a rounded hull will have less drag than one with
a hard chine hull, due strictly to the difference in wetted surface area.

Such an approach to designing would answer the
buyer's perrenial question "which kayak is right for me?".

Not if they don't understand the information. Most won't and they're not
going to be willing to learn about hydrodynamics in order to do so.

all part of the education of the paddling public.

I agree with everything you wrote below about the motivation to
buy a kayak but when it comes to the actual purchase people do ask about
which kayak is best for them, likely because they will be spending so much
money on the boat and accessories.

I think people can relate to how much power it should take a person of a
given weight to get the boat to go a certain speed than to how many pounds
of resitance the boat should have at a that speed, especially when you
tell them how much power an average person can sustain paddling. I also
think people could relate better to how tall they should be or how much
they should weigh for a given kayak than just to say "for light people" as
the brochures usually do. The data could be on a website rather than print
a more costly booklet to replace the brochure. All of thse numbers should
be avialable from desingers now, just restate and pass along to buyers.

It's very obvious that you've never worked in retail. I have
extensively, including owning a retail business. Your perceptions about
the buying public couldn't be farther off the mark. Most people,
especially first time buyers of a product, are CLUELESS. Most simply
want someone to guide them to a suitable product quickly and not screw
them over. It really IS that simple! If you were to start talking about
horsepower and other technicalities, their eyes would quickly glaze over
and they'll find a reason to leave, after which they'll go buy elsewhere
from someone who doesn't bore or intimidate them. I know this because
I've worked in businesses where technical data was widely available and
we always took the approach of educating people as much as possible and
helping them make the right decision for themselves (consultative
selling). In doing so, you learn that there is a VERY fine line between
enough information and "information overload" and that it's different
for every customer. If someone comes in looking for "a yellow kayak",
they're not going to hang around while you explain advanced
hydrodynamics to them. You set them up the best you can, offer as much
information as they'll tolerate, take their money and let them be on
their way. I didn't like the way I was forced to do business in some
cases, but I figured that they were better off if they came to me and I
at least had the opportunity to offer them useful information, than if
they went and bought at one of the "Marts" from some bored high school
kid who couldn't care less.

While you and I and some others here may care about performance data,
it's pretty obvious that most kayak owners don't and never will.

I've actually seen a lot of queries about "what kayak is right for me" and
I suspect its because of the high cost of the boats which makes people stop
and think. Kayaks and canoes cost more than bikes, skis, and skateboards.

No, it's because most people have no clue what they need and they're
looking for someone to hold their hand through the buying process. It's
also because most are either too lazy or too disinterested to do any
research for themselves. Many simply aren't capable of understanding
technical data (or at least they're convinced that they're not). You may
not like it, but those are the hard facts of retail. People like you and
I and some others here are but a tiny minority of the buying public.
Only the niche market companies will bother to cater to us, because
that's what separates them from the mainstream.

Brian Nystrom ) writes:
Michael Daly wrote:

On 1-Jun-2004, (William R. Watt) wrote:


wait just a darned minute, are you saying the data you presented is not
test data but is calculated from dimensions using Winter's KAPER model?
that's not data. sorry, it doesn't count as data.


No one does tank testing of kayaks. Too expensive. All data published
in Sea Kayaker is based on both KAPER and Taylor. Both produce similar
results. These calculations have been calibrated with real test data.

If you want better data, you'll look long and hard.

Better yet, do it yourself if you think it's so important.


Do you think I could get a research grant from the Defence Department?
Don't commandos, or whatever they are calling them now, use kayaks? Half a
knot could mean the difference between victory and defeat for an enire
invasion force. How do military policy makers measure the cost of kayak
research in body bags?

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Brian Nystrom ) writes:
William R. Watt wrote:

companies like Chesapeke(?) Light Craft and Pygmy Boats sell plywood boats
and kits make from computer cut panels. people buy the boats or they
can assemble the kits themselves and save a lot of money.

Compared to what? When you factor in all the tools and other supplies,
plus the time involved, there is no savings at all. Building boats is a
labor of love, not an economic expedient.

I've already mentioned the 1/3 cost savig nin building "stripper" boats from
a kit. That includes all the materials and assumes you have a few basic
tools on hand. Buildign boats is not a labour of love, it is mostly a way
of being able to afford the cost of the boat. I don't know where you get
this "labour of love" business. The same place you got the 2% hull
scratches friction, somewhere in the deep dark obscure recesses of your
imagination?


More importantly, what percentage of kayakers build their own boats? For
that matter, what percentage is even capable of it or has a place to do
it? You seem to forget that we live in a country where most people can't
even change the oil in their cars, let alone build kayaks.

enough people build their own canoeos and kayaks to make the selling of
plans and kits profitable. belive it or not there are even people out there
building birch bark canoes and teaching the building of birch bark canoes,
and canoe camping in the birch bark canoes they built.
building a small boat is not rocket science. I've lost count of the number
of webistes full of photos of novices building their own canoes and kayaks
every one starting with a comment to the effect, "Before starting to build
my own canoe (or kayak) I'd never so much as changed a light bulb. I was a
complet kutz with two left thumbs." and so on ad infinitum. I've read
somewhere some Brian Nystrom guy built his own first boat at one time.


While it's certainly possible to custom design and cut panels for stitch
and glue boats, no one does so. The closest thing to it is Newfound
Woodworks will take a customer's design and make the panels for them,
but there are even fewer people who can design a boat than there are
than can build them.

that doesn't mean it can't be done. I wrote that it could be done. I did
nto write taht it was beign done. There are a lot of things in this world
that could be done, or could be done better, that aren't. that was my point.

No kidding, but it's even more complex and time consuming to build one
than it is to do a S&G. BTW, I do build skin-on-frame boats, so I have
an idea what's involved.

I don't see your point. The major savings in building one's own boat is in
labour. You build it yourself to save the cost or paying someone
esle to build ti for you. YOu also save other costs such as "shop" costs
by building it in your garage, attic, or living room.


as for the preformance of flat panel (hard chine) hulls its actually the
turbulence at the chines which creates more drag at higher speeds compared
to smooth chined hulls. the wetted surface vs wave-making again.

While turbulence is certainly a possibility with a poor design, it's not
a given. The wetted surface area is what makes the difference. Why do
you think that EVERY racing boat made has a rounded hull? Read the
manufacturer's literatue and read basic information on boat design and
they all say the same thing: round hulls have less surface area for a
given displacement than hard chine hulls. A spherical hull would have
the absolute least wetted area, but obviously, it would no longer be a
kayak or canoe.

I think you'd better take another look at what I wrote. Hard chined boats
do have a bit more wetted surface but the turbulence at the hard chine has
a bigger effect, moreso as speed increases. (Lapped strake boats have the
same increase in resistance.) Interestingly, and contrary to what yoru
write above, a spherical hull does nto have the minimum wetted surface.
That's because only part of the shpere is immersed, ie. a chord of the
circle. John Winters (www.greenvall.com/winters.html) has some diagrams to
illustrate this. I thought as you did until I saw his examples.


some places you read about wetted surface vs wave-making. other places
its wetted surface vs residual resistance, where residual resistance is
any kind of drag that's not surface friction and includes drag due to
wave-making, poor tracking, hard chines, etc.

That's not the point, you can have two boats with the same wavemaking
resistance and one with a rounded hull will have less drag than one with
a hard chine hull, due strictly to the difference in wetted surface area.

nope, the drag of the hard chine hull includes the turbulence about the
chine which is greater than the difference in friction resistance. but
don't forget you can have a V-bottom hard chined boat which tracks better
than a round bottom hull with the same length and wetted surface and the
hard chined hull will have less residual resistance because it spends less
time slewing around, and more time going straight. as we have all seen,
the boat with the rounded bottom cross section will often have "deadwood"
added at the bow and stern or a skeg (or rudder) or both to help it track,
and these add wetted surface to the rounded hull.

It's very obvious that you've never worked in retail. I have
extensively, including owning a retail business. Your perceptions about
the buying public couldn't be farther off the mark. Most people,
especially first time buyers of a product, are CLUELESS. Most simply
want someone to guide them to a suitable product quickly and not screw
them over. It really IS that simple! If you were to start talking about
horsepower and other technicalities, their eyes would quickly glaze over
and they'll find a reason to leave, after which they'll go buy elsewhere
from someone who doesn't bore or intimidate them. I know this because
I've worked in businesses where technical data was widely available and
we always took the approach of educating people as much as possible and
helping them make the right decision for themselves (consultative
selling). In doing so, you learn that there is a VERY fine line between
enough information and "information overload" and that it's different
for every customer. If someone comes in looking for "a yellow kayak",
they're not going to hang around while you explain advanced
hydrodynamics to them. You set them up the best you can, offer as much
information as they'll tolerate, take their money and let them be on
their way. I didn't like the way I was forced to do business in some
cases, but I figured that they were better off if they came to me and I
at least had the opportunity to offer them useful information, than if
they went and bought at one of the "Marts" from some bored high school
kid who couldn't care less.

I agree when a person walks in off the street do not want to be
"overloaded" with information that has no meaning to them, however they
can understand information realted to their strength, weight, and body
size. They might not know anything about boats but they certainly do know
a lot about themselves. That's my point. The information should be
provided in a way that relates to the buyer, not the boat. It makes nto
sense to graph boat speed vs total resistance when it can just as easily
be plotted against horsepower with reference lines drawn for average (1/20
hp), athletic (1/4 hp), and absolute maximum sprinting (1/5 hp) power
output of humans. People will consult and use meaningful, relevant
information.

My areas of expertise in my former life was not selling boat but in
numerical computer systems and statistics. One my areas of research and
application was the graphical analysis and display of numerical
information. So I just might possibly also know of that which I write.

No, it's because most people have no clue what they need and they're
looking for someone to hold their hand through the buying process. It's
also because most are either too lazy or too disinterested to do any
research for themselves. Many simply aren't capable of understanding
technical data (or at least they're convinced that they're not). You may
not like it, but those are the hard facts of retail. People like you and
I and some others here are but a tiny minority of the buying public.
Only the niche market companies will bother to cater to us, because
that's what separates them from the mainstream.


I have to disagree. Blaming the buyer for the seller's failure to provide
important information in a form the buyer can use is a cop out. Sellers
who blame customers for their own failings are at risk of having someone
take their customers away from them.



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On 5-Jun-2004, (William R. Watt) wrote:

I think you'd better take another look at what I wrote. Hard chined boats
do have a bit more wetted surface but the turbulence at the hard chine has
a bigger effect, moreso as speed increases. (Lapped strake boats have the
same increase in resistance.)

The difference between hard and rounded chine in practice is negligible - at
least for kayaks. You'd have a hard time finding two kayaks that have a
difference that you could attribute to the chines and could also feel the
difference.

Interestingly, and contrary to what yoru
write above, a spherical hull does nto have the minimum wetted surface.
That's because only part of the shpere is immersed, ie. a chord of the
circle. John Winters (www.greenval.com/winters.html) has some diagrams to
illustrate this. I thought as you did until I saw his examples.

You'll have to be more specific. I looked at all the pages and figures and
can't see anything that specifies the characteristics of a spherical hull.
He has circular cross sections, but not spherical hulls.

If the spherical hull does not have the least surface to volume ratio,
please tell us what shape does.

Mike