I have seen boiling ribs as an alternative to steaming.
Last summer I met Hilary Russell, of the Berkshire Boatbuilding
School, while he was doing a workshop in Saranac Lake, NY. He
actually uses cedar ribs and boils them for his boats. It was
interesting to see how they went together. Of course the rib size was
larger than when using oak or ash.
His boats are similar to Platt's, but while Airolite boats go to
great lengths to make the hull rigid, Hilary uses lashing at the rib/
stringer joints and no kevlar for torsional rigidity.