A BOM for a 17 foot S&G kayak says it can be built from 3 sheets of 4mm okoume plywood. Each sheet of ply weighs 12 lb. If you pull up a weight for a similar sized sheet of whatever aluminum you intend to use you will have an idea of the handicaps aluminum possesses. To be competative with plywood the aluminum would have to be very thin and consequently would have very lttle rigidity. Aluminum boat manufacturers get around this by using stamped panels that are drawn into shapes that make them more rigid. It's not something you can do at home.
Every potential material has specific physical properties and the material with the most desireable characteristics wins. So far it's good old fashioned plywood held together with epoxy and fiberglass.
Two days ago I was paddling a 16' ultralite kayak that was constructed from 2 sheets of 3mm (1/8") okoume. A sheet of 3mm weighs 8 lb. and the basic hull weighed 30 lb. I don't think you can go there with any common metal.

: I am thinking of building a all aluminum kayak does anybody know if this has
: been tried before and if so wondering about the market for such of design.
: it will be designed and built very close to way aircraft are. i will be
: using marine grade aluminum and all riveted joints no welding.

: thanks
: steve