Thanks Mechsmith, I suspected something similar to what you described. Should be no problem.
On the attached pictures you can see what I have so far. The lower section of the rudder is just out of the gluing stage, so I haven't done any shaping on it yet. You can see the layers glued together with 3M 5200, I'll radius the leading edge and taper the trailing edge so it is shaped like a foil.
Again, the layers are two 3/4" slabs of HDPE (I think) (I don't know the exact composition of it - so we'll call it "plastic"). The outter layers are 1/8" aluminum. I used the plastic for bulk and light weight and it won't swell when it gets wet. The aluminum is there for strength.
The upper section is all aluminum, 1/4" plate with 3/4" aluminum barstock for spacers.
The tiller is 1/2"x1 1/2" aluminum bar stock. I wrapped the end with 1/4" rope to make a grip. There is a pin that will pull out and allow the tiller to fold down for storage when I pull the rudder off. It will also fold up and lock so its out of the way during anchorage, etc.
Over and out! Flat.