The Rise and Fall Of Swallow Tails

Swallow tails have been around since at least the mid-50's...

Carl Ekstrom built twin finned long boards in the 60's with a split tail...

 

The first modern/shortboard use of the swallow tail is attributed to Steve Lis' wide tailed kneeboard design, which was based on Ekstrom's split tail longboards...

 

But there's a hidden history behind the growing use -- and then loss of favor -- of the swallow tail on the pulled-in semi-guns of the early to mid-70's.

The deep V's of the late 60's, with their straight tail rocker, left a nasty spine behind the fin. That spine caused tracking in smaller, junkier waves...

Shapers tried to address this issue with things like the tri-plane V, which minimized the sharp spine behind the fin...

...and Morey-Pope introduced V in the middle of the board with a flat tail area with their transition-era Camel line of boards. An early version of "reverse V."

As boards got narrower and flatter, they maintained V through the end of the tail to loosen them up...

To help minimize the sticky spine behind the fin, shapers started using swallow tails, which, in effect, reduced the length of the spine behind the fin...

Here's an example of a modern Deep V replica shape that utilizes a swallow tail. You can clearly see much of the rear spine was removed by the swallow tail (the area depicted in red).

As design progressed in the mid-70's, tail rocker began to reappear behind the fin area. Shapers left that rear area flat, which resulted in "reverse V" ahead of the fin. The boards still had V, but the rear spine was missing, and the problem was largely resolved. The widespread use of the swallow tail was replaced by squash and roundpin tails...which were easier to shape, easier to glass, exhibited less cavitation in turns, and were less prone to damage.

(Proviso: This is just one design historian's perspective...)