Dont think Hydroptere did 50k in what you`d call open sea. Fair enough it wasn`t a canal but it was in a massive harbour.They flipped it in open sea 18 months ago; outer fin (partly resposible for opposing heeling) cant maintain negative lift (down force) in big seas, ie in wave troughs it looses force; boat can (and has ) flipped. For its size it still needs relatively flat water.
(Yes I know outer ama is also full of water; but foil does do its bit)
In rough conditions suspect WS is still fastest ???