The aluminium parts for the barrel and shaft bearing housing weigh 80kg.  There was quite significant modification to the hull to accept the barrel.  That has also added weight but would be less if incorporated in the original design.

As launched they had a sprung detent that would release with impact but that is going through further iteration to now incorporate a friction clutch that can be released and reapplied as required to hold the blade at any angle between vertical and horizontal in either direction.  The boat is moored with blades horizontal so they are clear of the water.

This system allows continuous blade rotation so blades can have a fine trailing edge.  Rudder linkages are  a series of belts and shafts.  In my view the orbital hydraulic pump/motors are a simpler option.  Tillers could also be used but the turning moment can get very high in the circumstances of a shunt when a rudder is left facing the opposite direction then rapidly turns to trail when speed is getting up.  

This gives an indication of the size of components needed to handle the forces on what is essentially a rotating dagger board.  Deep boards mean large moments and the structure to handle those moments needs careful attention.  

From a performance perspective I expect that rudders like this located to give perfect balance on the wind with the trailing rudder down and leading rudder up plus ability to raise the trailing rudder when reaching and running would work well.  The alternative is  much smaller rudder at either end and a dagger board in the middle of the hull. This arrangement also works well.

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