I've made a couple of cones from 1/8" aluminum for a friend of mine. I never thought about the use of these cones until they were done and I wish I had actually thought about the purpose before I had made them . Hindsite is a bit** :-).
He's making a boat, kind of a houseboat rig and has two pontoons to use on each side as stabilizers but he wanted a cone/point to weld on one end of each to break the water.
I made the cones up ( 6" x 19" x 20" high), welded them together no problem and in a moment of thought figured "damn, they should have been eccentric instead of concentric", flush to the top in other words so they would ride up on the water instead of plowing thru it.
My question, finally, how do you lay an eccentric cone out? I have the Audels Sheet Metal handbook, searched thru the web, but no luck, anyone.....Mike