You can certainly find both in GI.  Gaff tops have been plentiful by the eroded island on the E side of mile marker 6 of the BWW.  You can find it using your depth finder if you don't have the coords.  It goes from 6-7 feet up to 2. Just disappeared about 2 years ago.  Freaking hard heads are everywhere. 
 
That's a fascinating project.  Magnetizing the hooks themselves, or attaching something to the rig?  Can't wait to hear the results
		 
		
		
		
		
		
		
		
		
	
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