In article ,
Chris J Dixon wrote:

I didn't say they were useless - I said that they are NOT more stable
than tetrapods (as was originally claimed) and, in fact, are less
stable. Yes, you can fix that by increasing the base by about a
factor of two but, as you point out, that means they cannot be used
straight ahead and must be used diagonally sideways (or straight up).
I should be surprised if the tripod ladder in the link was enough
larger in all dimensions to achieve the same stability as the 10'
ladder I have

Which is?

Youngman's industrial 3m.

- yes, the width is ample, but what is the length from
the steps to the single leg, and how far is the step from the single
leg (in a horizontal direction)? With those figures, I could easily
calculate the relative stabilities.

The web site fills in some of those figures. The 3 m ladder has a
base width of 1.45 m and the spread to the back leg is 1.93 m.

Mine is 62cm and 191cm. If I assume the angles are the same, mine
has a 10% longer distance to the nearest imbalance point. But,
equally importantly, it maintains its stability when on the top
and reaching forward to work. That is a very big deal, because it
is the recommended way to use a stepladder and means that it can
really be used as a 10' ladder, not as an 8' one with a 2' extension.


Regards,
Nick Maclaren.