I’m trying to track down Mike Slingerland - master shaper of the early 70’s. I have a board I bought in NJ that I’ve done some research on and Ed Clapp over at Surfboards Hawaii thinks it may be shaped by him. The serial number on the stringer is 8012.S - apparently the ‘S’ maybe for “Slingerland”. A few pictures can be found at http://mywebpages.comcast.net/jonnybrown/images/board.jpg (sorry about the quality!) Just looking for confirmation (and to let Mike know I’m looking after one of his children!) JB 
Mike Slingerland IS a master shaper AND over looked. He’s still making beautiful boards the old fashioned way; handcrafted one at a time. Contact: (760) 436 7477. Tim