Re: [Paddlewise] Boat Design

Peter replied (snip):

>...Clearly a non trivial task requiring many years investment of time and
skill, but not at the core of the knowledge needed to design a boat.<

Yeah, I realize that, but the article did imply the kind of mental hard work
that goes into some of these buisnesses, design being the core unless one
simply copies existing hulls. Kit boats and plans don't become popular.
usually, without good design. I do wonder how some of these kit boat hull
designs recieved their initial inception. Did they go through the same
evolutionary process as Matt lays out on his website? I do know amongst the
buisneses providing kits/plans/completed wooden kayak, there can be tension
and legal wranglings from time to time too, so not all is always rosy with
that segment of the kayaking world, though I applaud guys like Nick, his
brother, et al for helping the masses have an affordable option to
commercial glass boats (well, with a little elbow grease). But like Shawn
pointed out in general, it is up to any offended parties to track down and
attempt to resolve the issues that are causing friction. I think some level
of discussion on groups like Paddlewise can be appropriate, but not all
would agree. I've certainly gained a wider appreciation of some of the
issues I did not have before, prior to Peter T bringng up certain inquiries.
I just wish at times the objectivism from all parties would extend the full
100%.

>That part of the design process, which considers the effect of the hull
shape on...turning ability, tracking, kayaker size and weight,  seem to rely
on the designer's experience of paddling, testing, building and selling many
boats, rather than physics or mathematical modelling.<

True enough it wouls appear, though some would niggle with your statement
and add that physics and math are all part of it too. Funnily enough, we did
have a destroyer-class navy vessel a few years ago in Canada, all computer
designed, fail its first sea trials (costing the tax payer a bundle if
memory serves me correctly).

The permutations are endless as Mr. Winters implied with boat design. The
wise paddler looks to buy newer designed kayaks that are tested/designed by
real paddlers and tweaked before being put into production. I think the
Tempest 180 is a good example, though I don't know the history/origins, if
any, of the initial hull design inception. I do think that the combined
efforts of various recreational paddling discussion groups, dedicated
traditional kayak discussion groups, club-written information sharing, and
the myriad of books, paddling magazines, web sites, etc, all make the task
of understanding the sport of sea kayaking in the context of boat
characteristics and the pursuit of better boats much easier, though I do
find opinion varies widley, enough that a given expert often directly
condradicts what other experts are saying.

>This shines out of Matt's description of the history of the Mariner boats
and seems to be an aspect of  kayak design that truly blends art and
science.<

Balancing the need for good tracking for open-passage making with the
ability to easily turn a kayak when needed is an aspect that frustrates a
lot of paddlers looking for the perfect kayak (for themselves), as well as
the designer I imagine. Matt and his brother have done an outstanding job
here, comingling the two flip sides of the coin. The other kayak that does a
wondeful job in my opinion, and like the Mariner line of kayaks has generaly
good glide characteristics despite its width, is the Gulfstream. I just
don't like how I sit in/experience these aforementioned kayaks, but it is a
totally personal preference obvioulsly. Matt claims his kayaks don't need
skegs, but some of the models do require sliding seats to optimize
efficiency while underway, so I still think the perfect boat hasn't been
developed yet (one with no moving parts other than the paddler). I do find
it interesting that most of the kit boat websites claim their kayak designs
obviate the need for rudders and skegs. Though subjective, I do think this
is an exaggeration. And gear capacity is a whole other realm when one does
view a good sea kayak with an eye to expedition paddling.

>If what I've said is right then I wonder to what extent the kind of
experience necessary to design a kayak can ever be reduced to rules of thumb
or equations. Perhaps with some designers instinct may serve better than
analysis. I also wonder about the kind of thoughts and experience you will
apply in designing your boat and hope you will keep us up to date.<

I often wonder how the folks at Current Designs, Seaward, Necky, etc., come
up with their designs. Do they hire navel architects, pay consultant fees,
experiment and play - having hired (or are) intelligent, creative
individuals. Personally, I'm headed toward a steep learning curve myself
with respect to executing design (lofting, offsets, etc.). And I've been too
busy splashing my kayak all over the coast for the last two decades to pay
much attention to hull design equations, etc. I do know what I like and
don't like, and where I can improve on what I have. I hope that will serve
me well. I certainly have the ability to manipulate wood to benefit from
some of its inherent properties and work the situation where those
properties resist the builders will. I don't want to too severly challenge
the design to the point where it would be easier to go back to fiberglass
which contorts to any shape.

Here is a top-ten list of prime considerations:

1. The hull must be strong. This may rule out hard chines. I feel semi-round
produces the strongest configuration, but can't back that up scientifically
off the top of my head. That profile at least must catch less guff
sideswiping over reefs.

2. The boat needs to be fast. The ability to move away quickly from danger
or work away from a lee shore is a must in areas prone to sudden squalls.
Again, a round bilge hull normally yields less wetted surface and a quicker
boat - all things being equal (and they never are).

3. The boat needs to be long. Again, the need for speed is paramount. Some
of the faster, really long race-type kayaks are a hoot, but not in any kind
of real sea. 17 to 19 feet would be my max. parameters, navel architecture
aside (and ignoring some of the shorter kayaks that have a good turn of
speed).

4. The boat needs to be narrow, 19 to 21 inches maximum. I don't paddle to
take pictures or fish. Ocean kayaking takes place in waves. One must be able
to readily lean into the action and remain perpendicular with good paddle
form. Narrow usually means fast too.

5. The kayak must be low-profile. The sea is a windy place. I'm appalled
with some of the sea kayk designs intended for open ocean. My preference
runs toward a wetter ride in order not to scarifice the lower profile.

6. The kayak has to track well without a rudder or skeg in a variety of wind
and wave conditions. This will be challenge to design. My Nordkapp tracks
much better (in a device-free mode) with edging and leaning. This can be
very difficult to maintain in heavy seas due to lack of solid initial
stability with this particular kayak (the emphasis here being holding
course). I may still add one of said devices as back-up.

7. The bow must carry the front of the kayak over the waves and not bury
itself, especially in following seas. This can be more difficult to achive
than it first appears, while maintaining reduced windage (IMHO). I was very
dissapointed with the Necky Arluk II which I believe was an attempt to fix
some of the Nordkapps difficulties in this regard. I watched one in
increasingly more difficult head seas for 7 hours once on a long, ill-fated
crossing. It plunged worse that the Nordkapp, then resisted coming back up.

8. A choice must be made between Swede and Fishform. If I go Fishform, I'm
going to need a bit more fullness in the stern to aid tracking and increase
seaworthiness.

9. The kayak must be an extension of the body. Ideally, one should hardly be
aware that the boat is even beneath you. Very few kayaks other than
traditional craft offer that (but they suffer a small payload capacity
(again, IMHO).

10. The craft must be astetically pleasing. Pleasing to my eyes, anyway. And
pleasing to my soul. I throw my whole spirit into paddling when I'm out on
the sea, even for a short trip. I can't imagine renting a different kayk
(one I'm not happy with) for a wilderness sojurn, and still experience the
journey the same way. This is probably a failing on my part. I've always
been a firlure to myself. But I do have fun, and hope my next kayak will
provide that.

> By the way I'm a friend of the Nadgee designer Dave Winkworth. I also have
a great respect for Matt Broze, and his generous approach to sharing
knowledge. So I don't want to enter into the boat copying debate, though I
would dearly love to hear Dave and Matt get together and talk it through one
on one, maybe over a bottle of good wine but that might be hoping too much!<

Anyone who does not have respect for Matt, even if you dissagree with him,
is a complete impbisile. He can push the conspiricy theory a bit at times,
but it is only because his mind is working at 90% more capacily than the
rest of us (well, some of us). Wine? How about some wine, a moon filled
night, with kayaks sitting above the high-tide, glistening with hope for a
new day of uderstanding for the 'morrow.

Some design insiration. Anyone knoe the story on this?

http://www.qajaqusa.org/gallery/New_Zealand/Tutakaka_flyer

Shawn in a Night Herron (a kit boat with rat promise. Anywone lnow its
capacity?

http://www.qajaqusa.org/gallery/New_Zealand/shawn_spine_rolling

Doug Lloyd (who's wife peered over his shoulder tonight and said don't
forget design point number 11: "Finish the house resnovations and all the
furniture have done, before you can build a kayak. Then I got the silent
treatment, which of course, I don'tt mind!)

Vicoria BC
***************************************************************************
PaddleWise Paddling Mailing List - Any opinions or suggestions expressed
here are solely those of the writer(s). You must assume the entire
responsibility for reliance upon them. All postings copyright the author.
Submissions:     PaddleWise_at_PaddleWise.net
Subscriptions:   PaddleWise-request_at_PaddleWise.net
Website:         http://www.paddlewise.net/
***************************************************************************