Shape of Rudder Blade
FYI, ref the comments on the shape of the rudder foil, older Wayfarers had shorter, rounder rudder blades but over the years the majority of racers moved to longer high-aspect ratio blades which worked better, the theory being that they projected further below the turbulence from a centreboard box which was then not permitted to be fitted with a slot gasket.
About ten years ago slot gaskets became legal under the class rules and pretty soon the longer rudders largely disappeared in the racing fraternity, as there was far less drag and turbulence and helms now prefer what is claimed to be the better feel of the shorter, rounder rudder blades.
Dagger Boards & Dagger Rudders
I believe that some dinghies have a rubber shock absorber or sacrificial fixing in the dagger board / dagger rudder slot to take the shock out of grounding in order to minimise damage to mouldings or foils. Maybe this is something to consider in the BC26 as it has a dagger board and twin dagger rudders.