Ah , the whole historical run down.
Prior to 1958 all surf craft were crafted as hollow plywoodsurf ski or strange Malibuish hollow things from Popular Mechanics magazines with of necessity square boxy rails and leaky seams.
A whiskey bottle cork provided a cork for the bung drain hole.
The Balsa can from the tin covered liferafts on soon the razor blades retired navy ships.
the rafts were about 15ft square and about 3ft thick. they could be bought for next to nothing as the ships were stripped of everything of value before be towed off to be melted down.
The major surf ski manufacturers shaped up to the new type of board, Bennett, Gordon Woods, Scott Dillon hired and trained the next generation of board makers .
Home grown boards flourished but were often pretty ugly.
Foam came in around 62 and surfing just exploded.
Factories were all around my high school and lunch was about dreaming of how you could save £37 for a new board.
Production lines were established to meet the demand and each manufacturer had a team of hot surfers shaping, sanding or glassing ( the next wave of board makers)
Check out the fins
Occupation health and safety was no existent , factories burnt down and it was a wild west time.
one pay back story was a peed off ex employee deliberately mixed a foam mix to double strength and let it loose in the blank blowing room where the doors opened inward.
The foam expanded and filled the whole room with the doors being unable to be opened.
Mayhem ensued.

The picture is of Dee Why Point, where I learnt to surf after being allowed out of the basin, it was a big day in your surf life where the old guys allowed you to come out the point. (That was genuinely enforced) Proud moment when you got the nod.
I've taken up troll hunting just for fun, instead of a rifle I'll just use a pun! 冲浪爷爷