@ Jake, yes it's the Inter 18

@ Orphan, 1 sitting in front of the mast, the other at the rear beam

@ Orphan & Catman, This might be it. We do lower them, but maybe not enough/ too late??

@ Tony: Really? You go out on the spi?

So to summarize:It is acceptable to use one or two dragging rudders, we should lower the boards as soon and as far as possible.

Thanks again for the usefull help!