The blanking plate works well, and with four crew on board it is essential to fit it. Otherwise far too much water sloshes up into the cockpit and the self bailers in the sumps can't empty it quickly enough. Fitting the plate under way was very difficult. The space under the outboard is cramped and awkward to get at. The force of up welling water pushes the board out of the way until you can finally twist the locking bar in place. I have modified the set up.
The short forward length will be hinged to the side of the opening with nylon hinges, so it can be flapped down when needed.