Colin Archer's wave line theory

[Proteus]

I read from some here that it's obsolete.


Are there anybooks out there that may go into more detail?


Any comments would be apprieciated, thanxs !

-Brian

[Gilbert]

You might start a debate with this one.
My take on it is that it is not so much obsolete as that it is not absolute.
Certainly many very nicely modeled boats have been designed whose displacement curves closely match the shape of the graph of the sine wave. And if your displacement curve is too ragged you might consider doing something to "fix" it so it is smoother.
Google 'cosine wherry' to see one example of a very pretty and successful rowing boat that followed this approach in its design. Sorry I can't remember the designer's name.

[jehardiman]

I concur with Gilbert

No "theory" or method used to design a hull is ever really "obsolete". What happens is that other theories or methods come along that better fit the needs of the time and available calculation/fabrication materials.

Archer's work was closely linked to the mathamatical hydrodynamics of the late Victorian period, where the search of simple, constant, "natural" relationships predominated. Froude, Reynolds, Michell, and Kelvin building on work by Bernoulli and d'Alembert followed this path, however they could not handle viscosity effects, which were finely brought to fruition with the work of Havelock and Wigley in the 1930's. Archer falls into the early part of this period, and while his hulls had many good qualities that they inherited from nordic sea boats, the theoritical basis for the use of geometricly basied hullforms has largely passed.

Edit to add: Look up John Scott Russell and wave theory for where Archer got the idea.