Paul
I don't know how much help this might be but it's the way we did the twin rudders on many of the Model Slipway kits.
You make a jig to suit the model with the two rudder shafts (or similar material) just pushed into the wood and spaced to suit the rudders. Ideally this distance should be a little wider than the prop shafts so you can withdraw them past the rudders without having to take the rudders out.
Clamp the jig flat down to the bench and lower the hull onto it, with the upright shafts protruding into the holes for the rudder tubes. Pack the hull so that the deck is level in both planes - this will ensure the rudders are exactly at 90° from all angles. Now thread the brass rudder tubes down over the shafts so that they stick out a little below the hull bottom, and slap some P40 all around the bases and onto the inside of the hull. Take care not to get any filler onto the shafts. Once set, remove the hull and your rudder tubes are fixed. File flush with the hull on the outside and add more P40 if required. NB P40 is the stuff with the chopped-strand glass in it, not the smooth body filler.
Good luck.
Dave M
Sketch of jig:
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Topic: rudder mount problems on a v shaped hull (Read 2384 times)