: You are quite right about the feeling of stability being a very
: subjective thing. Saying that one kayak would feel four times as
: stable was largely my way of trying to use simple layman's terms
: and avoid technical terms. I should have said that according to
: the formula used to calculate stability, one kayak had four
: times as much righting moment at about 20 to 25 degrees as
: another kayak the same width.

: Of course the formula used to calculate stability just gives a
: rough guide for the purposes of comparison. As you have said,
: waterline width is more significant than maximum width when it
: comes to primary stability and it is usually primary stability
: rather than secondary stability that less experienced paddlers
: use to judge how stable a kayak feels. I mentioned the
: importance of the hull cross section and just one of the ways
: that affects stability is that different shapes with different
: amounts of flare will change the waterline width.

: As well as those obvious things that we have mentioned, stability
: will be affected by other things like the paddler's build and
: the height of the seat. A tall male with broad shoulders will
: destabilize a kayak much more than a short female who is more
: pear shaped. I have read that some designs of kayak can have
: their stability halved by raising the seat just one inch.
: However, most sea kayaks would not be affected quite that much.
: Then, as you have said, different paddlers can have quite a
: different perception of the stability of the same kayak.

: Even looking just at the waterline width of a kayak is not a
: particularly reliable indication of stability. Most people are
: surprised at how different two designs with the same waterline
: can feel and the formula confirms that there can be a
: significant difference in the righting moment.

: I think we might both be trying to make the same important point.
: Stability is quite a subjective thing and certainly can't be
: judged by simply looking at the maximum width of the kayak.

Within reason this is all true, but an 18" wide kayak isn't going to feel stable to anyone new to the sport, even if it had dead flat sides and had an 18" waterline beam.

Bill H.