On my trainer, I bent a piece of 5/32 rod into a 90 degree angle and drilled a hole to accept a nylon link and inserted it into the nose gear mount (see pic). Then ran a flex rod from it to the water rudder. I think im going to "revamp" it though and instead of bending the rod, im going to put a steering arm on a straight piece of rod and run them that way. The only thing I had trouble with is to figure out how much throw i needed in the arm and of course the slop that comes with using flex rod. The water rudders dont want to center exactly with the air rudder. My only advice there is to try and keep the flex as straight as possible. Hope it helps.