I had a Shockwave 55 and I believe the tube was 11/32" with a teflon liner.If your's is the same you could cut the tube off where it exits the bottom of the hull and leave a little on the inside to slide a 5/16 " tube through it,thus eliminating the teflon lined tube.You would have to bend the new tube to run it toward the transom.You could also cut the tube out of the hull and patch the area where the tube went through the hull and run the brass tube inside the hull bottom to make it surface drive.
