This isn't going so well. The blade is twice as thick at the top end, the part that's inside the stock. So, to take some marine grade Al, cut it to shape based on the old blade, cut two more smaller pieces and laminate / weld them at the top end to the required thickness, drill the eye-hole where it pivots and fit a bush inside, turns out to be a fairly complex bit of metal fabrication and I'm looking at a £500 job and two weeks elapsed time....
I suppose the alternative is a flat 9mm sheet of marine Al cut to size, and at the top end use some plastic discs as spacers to fit it snugly into the stock or something.
Lionel, how does your new blade fit into the stock, or is yours 16mm thick all the way down?
Alistair