http://bit.ly/1p0Gin8
Low quality scan, probably from a periodical, of model yacht sailing, attributed to the L.A. area. The "W" on one sail identifies the boat as being from the Wilmington CA club and the style of boats makes it likely that this undated picture is from pre-WWII.
I figured you guys would be able to identify the location from that roller coaster in the background.
Cheers,
Earl