Assuming the platform is a floating platform, the height of the
platform above the water level should be somewhat constant. What if on
one side of the platform you drop two or three "L" shaped boards,
tubing, etc., padded, with the lower leg of the L about 3-4 inches
submerged, sticking out about 18-24", parrallel to the water surface.
Then you paddle broadside to the dock, pull your boat up on the legs
and slide yourself sideways up to the chickee, tie off, and unload.
You could shape the L's with a little dip in the middle so the boat
would "cradle" in it a little for stability.
Scotty, from SmallBoats.com