Steel-made hull with fiberglass-made radius chine ?

Thank you very much mydauphin,

It is the first time in this forum I am informed that something like that really worked, so it is very encouraging.
I have thought of removable plastic fairings, mainly because of the uncertainties about the whole endeavour, and of being able to repair them ( every, say, 3 years...) without touching the steel plates, but I admit it would be much more complicated to attach them firmly on the outside surface of the hull. As we all agree, we have to obey the KISS principle...

 

I would not advice a radius hull either, dear lazeyjack, if I could build a perfect round bilge hull like the one of yours, posted above. As I have said, it is the play of the light upon the steel surface that spells the difference between amateurs and professionals, and this hull looks like a fine professional hull to my eyes...
There is deep feeling, may be of Homo Faber era origin, that compels us to built a boat with our own hands. If this thing, made of flat and heavy elements (like the steel plates), at the end of the looong day is round and floats, it would be a real miracle to me...Thank you very much for your generous offer.

 

What is the length limit of a frameless steel hull of a sailboat, if there is any ? The closed shell, formed by the welded steel plates, seems a quite sound structure to me. Shell structures need not be heavier than skeleton/skin structures, isn t it that so?

 

There is a real limit. It is a function of panel sectional modulus to loading. There is also a practical limit. It is function of weight to loading and fabrication difficulty/cost.

It is possible to build a shell structure no heavier than conventional framing, however the cost and loss of volume/increased compartimation make it a poor choice for a structural system. There are good reasons that vessels are framed like they are.