The Classic Designs were the first range of Wharram catamarans, designed in the 1960s and 70s, based on the sea experience of James Wharram's pioneering ocean crossings. They are sturdy, very stable, but relatively basic in design. They are built using simple plywood construction over a backbone and bulkhead frame. The Building Plans for these designs are not as detailed as for the later designs, but as the construction is simple are still easy to follow. Design Improvement packages are available to update the Classic Designs, whether building new or renovating an existing design.