Developments in industrial and manufacturing technology made during World War II extended to the surfboard world in the late 1940s and early 1950s. The most lasting and important development in surfboard design occurred in the late 1950s with the phasing out of wood in favor of fiberglass and polyurethane foam. Board maker Pete Peterson made the first fiberglass board in 1946, built around a redwood stringer (a center board), then covered and sealed with fiberglass tape. California builder Bob Simmons came up with the "sandwich" surfboard a few years later: The board had a foam core, which was then encased in plywood, along with balsa wood outer rails and a coating of fiberglass for waterproofing. The selling point of foam is that it's incredibly lightweight, making boards easier to control (although foam boards at the time were so light they weren't terribly buoyant). Foam is also much easier to shape and cut than wood, allowing for quick mass production.
The increased availability of surfboards in the 1950s fueled the explosion of "surf culture" in the 1960s, allowing the sport to spread worldwide, in part thanks to "surf bands" like the Beach Boys and Jan and Dean, as well as movies like "The Endless Summer." And as hardwoods were gradually replaced by synthetic materials, one more holdover would go by the end of the '60s -- board length. Superlight, 10.5-feet (3.2-meter) long boards were tough to maneuver over waves, and by 1969 builders like George Greenough and Pete Brewer helped spur the dominance of 6-foot (1.8-meter) shortboards, or "pocket rockers." Longboards allow surfers to ride waves vertically; shortboards allow for that, too, but they can also carve turns, giving a surfer more freedom for stunts and personal style.
Synthetic materials were also more flexible than wood, and so the new pintail fin could be put to use -- it added stability in a wave pocket, which the shortboard couldn't offer without the pintail.
The modern surfboard had arrived. But it wasn't done evolving.