3 Classic Displacement Hulls: #1, The Plank


As I recall, back in the 80's Leonard Brady built a solid wood board based on the "planks" from the first half of the 20th century. The thing that struck him, after he got past the gorgeous aesthetic of the whole thing, was how the board delivered a sensation of flying that he'd only dreamt of. Somehow, over the post-war decades, board design had become so "refined and sophisticated" that the feeling of roaring towards the beach at a hundred miles an hour had been lost. But now, with a round bottom, 120 pound wooden board under him, Leonard was feeling it for the first time.


 Commonly referred to as "planks," solid boards were generally made of wiliwili or koa in Hawai'i, while mainlanders used redwood and pine.


They are the oldest known board design, easily over 300 years old. Planks also serve as the baseline for modern hull design. With no fin to influence the performance of the board, it took the right combination of outline and bottom shape to give the rider control as they flew towards the beach.


Planks were flat and heavy because wood was flat and heavy (that's why they were called planks...duh!) but neither of those "negative" qualities was seen as a problem. That's just the way it was, and boards evolved around those limitations.

Designers looked to sea creatures and canoe hulls for inspiration...both of which were intended to go through the water, rather than over it. So that's the approach they took.


Bottoms were rounded, usually all the way up to a dead flat deck. And there was no fin, so the outline template had to flow naturally through the water. Too much curve and the board would spin out of the wave immediately. Too little curve and the rider had no chance of changing direction or correcting for mistakes.

What worked best was a forward wide point and a moderately wide square tail.


The round shape of the bottom, while crude to the uneducated eye, was carefully fussed over by shapers.


Planks remained in use well into the 40's, even though hollow Blake paddleboards had made inroads due to their lighter weight and ease of transportation.


The post-war era even saw a few planks sporting small fins, an improvement borrowed from Blake's work in the late 30's.


What interesting is that of all the designs from our past, planks are the one "old school" genre that modern day hull surfers aren't inclined to replicate and ride. Simmons boards, Velzy pigs, D-Fin longboards, Yater Spoons, even finless Hot Curls...they all have active followings. But until you see a redwood plank in Kirk Putnam's garage, you can file them under the heading, "Gone But Not forgotten."



3 comments:

harmless neighborhood eccentric said...

Science!

tuskedbeast said...

Why no modern takers... interesting indeed. The weight, the lack of fin... perhaps the "clunky" template (compared to the sleek Hot Curl) is the third strike?

Great series, Paul et whoever's next.

PG said...

Speaking for myself...I'm afraid I might kill someone with one of these things. You'd have to be completely by yourself to ride one safely!