Sounds like you guys have made up your mind that CG is the issue, and
that adding weight to a boat can't possibly make it unstable, and that I
don't know what I am talking about, so I think I am wasting my
breath/typing.

Let me make one last try to support my position.

1. My friend, who is kind of a skinny guy, but is about the same height,
had no problem with the kayak. He is not an expert kayaker. We later
went out offshore into some waves in the Pacific ocean, he in that kayak
and me paddling a windsurfer hull, neither of us had problems, we went
snorkeling, and then climbed back on and paddled back in. This was not
an ultra-narrow high performance narrow sit on top, it was a cheap
recreational type of sit on top, which one would expect to be pretty stable.

2. If the center of gravity is the issue, how come my buddy had no
problem with the boat, and I could not keep it upright for 10 seconds in
flat water, once I lifted my legs out of the water? I am not that bad a
paddler, and since he is the same height, his center of gravity would be
about the same. But maybe you guys think that I am not only incorrect,
but an incompetent paddler. That is probably the only way you can
logically defend your position.

3. He warned me before I tried it that I would probably have trouble
with the boat, that I was too heavy for the boat. He said that his
daughter usually used the boat, and the boat was probably sized more for
her than 200 pound men.

The only way to settle this issue scientifically would be to take that
boat with a medium weight paddler, and gradually add weight to the boat
to make the total weight (paddler plus dead weight) equal to around 200
pounds, and see how the boat performed. Obviously I think the boat
would become unstable, and you guys think that the boat would not become
unstable. Since you have never seen a boat become unstable with heavy
loads, you think it can't happen, but it happened to me.

As I said, you guys are not going to listen to me, so I will shut up. ;-)

Richard



Marsh Jones wrote:
Richard Ferguson wrote:

I do not buy your argument at all. If the issue was center of gravity,
the trunk of my body, where most of the weight was, did not move when
I pulled my legs out of the water. Also my legs were on the deck,
just a few inches above the waterline, so the change in center of
gravity was minimal. However, the effect on stability was extremely
dramatic. (I am less than 6 feet tall, so my center of gravity is not
unusually high.) In other words, I can't see how a very small change
in the center of gravity could effect a dramatic change in boat
stability. There has to be another cause.

Nope - with your legs in the water, your CG is definitely lower - and
near the pivot point for the cylinder on which you are sitting. When
you move your feet up into the well, now everything is at or above the
pivot point. A regular kayak keeps a significant amount of your weight
below that pivot point and makes the kayak much more stable. I know
this oversimplifies the math, but that's my .02 and I'm stickin' to it:-)

Remember that this was a sit on top type of kayak, kind of like a
surfboard with depresions for the butt and feet. Most of the kayak
was underwater even before I pulled my legs out of the water. I think
that part of what happened was that the extra weight of my legs put
even more of the kayak under the water, and that affected the hull
design. It started to look more like a submarine than a conventional
boat.

Depending on the particular type of surf ski, many of them are about
like balancing on a bowling ball. Many of the competition skis are
18-19" wide, and take hours of practice to ride successfully, much less
get used to paddling with a wing paddle. The extra height above the
water gives you a lot better leverage once you get used to sitting
balanced on such a skinny boat, and they are darned fast when paddled
right.

Marsh
Minnesota