On Sat, 02 Sep 2006 01:24:14 GMT, !Jones wrote:

On 31 Aug 2006 21:38:24 -0700, in rec.boats.paddle "Hanta-Yo-Yo"
wrote:


!Jones wrote:
On Wed, 30 Aug 2006 17:53:26 +0200, in rec.boats.paddle Wilko
wrote:

!Jones wrote:

Yes, well, I believe I acknowledged that as an issue. Designing
*anything* is full of trade-offs... this is life. My issue is that,
left without a sanity check, I'll put so many gadgets and gizmos on it
that it'll need the extra flotation just to stay on the surface.
snip
Jones... who is going to mount a harpoon gun on the front... Sharks,
you know. (Do depth charges work better?)

LOL!!!

I'd go for a big laser, so you can also get rid of those pesky aliens
trying to abduct your boat! ;-)

Well, just lookin' around on the trusty old Google, I see that ama
boats have quite a devoted following, particularly down under.

Jones

Check out Yahoo Groups, Sailing Canoes, they have many threads about
ama! HYY

Thanks. I'll do that.

I'm looking at a $300 - $400 add on to an existing boat and wondering
if I'll see any improvement in flat water stability with a load... and
sometimes a sail. Thoes guys design the ama in from scratch and take
far bigger water than I ever will.

But... yeah, they're worth reading; I'm doing so now... and wondering
why the topic gets such a violent negative reacrion here. Obviously,
they're not for everyone.

Jones

Jones

Amas spell sponsons for a lot of folks who had to endure the
enthusiasm of a particular sponson inventor, who tried to get
legislation passed such that all small boats would have to use his
product. This would have been a sweet deal for him, and though he
indicated that the safety of the boating public was his only concern,
and all those drowning children that the boat owner would be
responsible for, it seems that the amount of money going into his
pocket was the real driving force of his crusade.

Also though he advocated his sponsons were the answer to every boating
safety issue, they infact created many new hazards. One particular
product tester, actually almost drowned during a test, because of his
inability to recover from an overturned kayak. Others had similar
experiences, and as Wilko indicated they are definitely not desirable
on WW kayaks where you want to be able to roll and recover.

The use of amas on a sailing canoe, is entirely different from
sponsons. You can get more info on sponsons probably by googling. I
will mention that many SOF kayaks use internal sponsons to add
flotation, and tension the skin of the kayak. My 1973 Folbot Super
does not use sponsons, and so tensioning is based on a very close fit
of the skin to frame. Also I have to have additional flotation bags
inside the hull of the kayak. On the other hand, the Klepper that I
had did use internal sponsons, to tension, which made assembly much
easier.

I stress internal sponsons, in contrast to the external sponson that
were to be attached to the the outside of the hull. These were
attached with straps around the outside of the hull of the canoe or
kayak, at appoximately the waterline, and would theoretically increase
the initial stability of the boat. However, WW and sea kayaks in
particular are designed with a lot of initial instability, in order to
allow the kayak to roll and recover. With the sponsons attached, the
boat would eventually roll, and then be difficult to recover.

The initial instability, is also used in manuevers where the kayak
would be turned or braced by laying over on the side. Bracing occurs
where the water may go vertical ie a wave face, and you want to be
able to remain vertical yourself, though the kayak is laying on its
side relative to the water. Now if the kayak is initially stable, the
boat will want to sit flat on the wave face, which will likely end up
with you doing a Maytag manuever, with the added distraction, that you
cannot recover. Most kayakers did not see this as a desirable
predicament.

Basically, what the external sponson did, is change the design
characteristics of the kayak hull, and in the process introduce
undesirable characteristics. Hull design has been around for a long
time and to go messing with it is inviting disaster. The ama also
changes the hull speed of the boat, by acting as a drag. Paddling was
like driving with your brakes on, which may be okay when under wind
power, but uses a lot of energy otherwise.

Amas, and in particular in reference to sailing canoes, are a
different matter, and though they also change the design of the canoe
hull, they do so in a predictable and desirable way. Or at least if
properly done and understood. But then a canoe is not typically rolled
like a kayak, and a kayak is not typically sailed as a canoe could be.

The Folbot Super is actually more of a decked canoe with a smallish
cockpit that can be fitted with a sprayskirt, but with a 37 in beam,
they are not typically rolled. They are also not usually used in WW or
vertical water with a lot of bracing required, but they are a lot of
fun to sail. However they are not as beamy as a regular sailboat, and
with out a keel board, or weighted keel, they are fairly easy to lay
over on their side expecially while gibeing. So I have considered the
use of an ama during sailing.

The problem with the ama, is that it will affect the way the boat
handles while paddling, which then becomes a trade out. Also the ama
is not a cure all for sailing either. The sailing canoes of the South
Pacific, where not tacked like typical sailing ships, but instead the
proa was sailed by shuttling the mast and sail from one end of the
boat to the other, that way keeping the ama always on the windward
side of the boat. The single sided ama would allow a boat to be
recovered by rolling to the side without the ama. This setup worked
well in the Pacific, because most of the sailing was done in
prevailing winds that allowed for long reaches that did not require
constant tacking. Also because the ama was on the windward side, the
aka would hold the ama out of the water so that the ama would be
barely skimming the water, and would place little drag on the proa.
The ama in this configuration is not actually providing additional
flotation leeward to keep the proa from going over in the wind, but
instead allowed for more aggressive hiking of the crew who would hike
way out on the windward ama to counterbalance the sail power. Infact,
many of the ama provided marginal flotation, and acted more as a
counterweight like used by a tightwire walker. This is contrary to how
most westerners want to use the ama as additional flotation.

Modern sailing vessels typically do not move the mast in order to
change the sailing characteristics of the boat, so the use of a
outboard float to allow the use of more powerful sails such as used by
the seagoing trimerans, does result in a higher speed as evidenced by
the open sea races across the Atlantic. However when the sail is
overpowered, the result is an overturned boat that will usually
require a crane to set it upright again. So unless you carry a crane
in your tender craft, the use of a floating ama especially on both
sides of the main hull can have mixed results even in a modern sailing
craft. Which at this point, as you Google, you will find that the pros
and cons of ama/aka, are one of the ongoing discussions of the sailing
industry and boat designers.

Adding a 5 gallon drum to the end of a aka attached to the gunnel of
your sailing craft, may or may not prove advantageous. The proper
design and use is not as easily understood. So, Go carefully, which is
part of the fun of trying to go at all!

Folbot, Balough, and others make sailkits that include ama/aka and can
be modified and added to most kayaks and canoes! HYY