scaling applied to multihulls

[peterchech]

I am not seriously considering scaling up any designs in the near future, but after reading many posts about the scaling up of monohulls and the laws of "mechanical similitude" I got to wondering ...

general consensus seems to be that, for the most part, a monohull can be safely lengthened by up to 10% without negative consequences, often gaining in stability. This can be done by simply increasing distance between station molds. Does this apply equally to a cat or tri?

general consensus also seems to be that increasing the overall dimensions of a monohull shouldn't be done more than 2-3% if at all. Again, multihulls?

[gonzo]

Whenever you change the overall dimensions by more than 10%, you need to re-engineer all the structure. That applies to multihulls too. For example, a 10' wave will be 100% of the length of a 10' hull but only 20% of a 50' hull. The stresses and handling are very different.

[PAR]

The laws of mechanical similitude apply to kitchen chairs, office desks, mutli hulls and everything else alike.