Flex tail SUP surf boards

[Pierre]

Did any one shaped /tried flex tail boards?

here a interesting topic from a SW France shaper;
http://www.forumdesup.com/t6220-short-sup-flex-tail
for those who cannot understand. at least few pix to be seen...
http://www.forumdesup.com/t112p900-montrez-vos-jouets#67440
I have a new project with plywood and wood structure/ foam rails. natural flex of wood can be awesome. idea is to insert air chambers between bottom and "rigid" part... as a flex control device!
here is sketch of project.
cannot ind other ideas / pictures of what has been done

[blueplanetsurf]

I think it's a good concept, the harder you turn off the tail, the more it flexes and the more rocker the board has.  
I remember seeing the "Tinkler Tail" on windsurf boards back in the late 80's, when everyone was trying all kinds of crazy stuff, kind of like SUP is today.  
I think it worked well but due to the additional weight, cost and moving parts it never took off.  Here are some pictures I found online.

[sup_surf_giant]

I'm trying to wrap my brain around this...

[gr8laker]

What's the benefit here, increased tail rocker as the tail flexes? or the spring after you unweight the tail at the end of a turn?  I can see an air pocket maybe having flex, but not spring. 

Water is so soft too...  I can see how flex is a key element to carving on a snowboard for example, where you're on a hard surface (not talking about snowboarding in powder)..  I guess it's something you have to experience on a surfboard to understand.

[Pierre]

During a turn, especially "on the rail", the purpose is BEND and/or TWIST of tail to increase curve of rocker and rail for sharper turns.   Bend should be favorized by weight on back foot, twist by weight on buried rail. For that reason I believe it may also ease board control in choppy condition, despite wide tail. and while weight transferred only on front foot, that means much flatter rocker, for speed on "flat" waves.
the spring effect is given in that case by the wood/ fiberglass: purpose is to restore energy stored in bended/twisted  tail at end of turn, when rocker flattens again.  flex fins are giving the same kind of effect.
Air cushions: idea is for adjustment of flex, depending on conditions.

Compared to thick stiff SUP boards, surfboards are thin, and so, especially polyester/PU foam ones, are much more flexible. there is an interesting article about surfboard flex in surfer's journal , I think it's no. 77.

This is only my point of view. this has been already experienced, major drawback being increase of weight and complicated construction.
I guess that experiment on windsurf board ( Tinkler) was given up due to the facts that a windsurf boards is subject to very high stress. now this is experimented again using soft foam inserts and this sort of things.

[Pierre]

some project from McTavish recreating the Greenough spoon concept::
http://www.mctavish.com.au/_blog/McTavish/post/Flexi-time/
... on my side some "V "flex idea..:

[SoCalSupper]

I'm trying to wrap my brain around this...

Whoa!-just saw this-yeah me too!
Giant-is this similar to the whole hard/soft tail thing with MB's?-kinda?

[raf]

A graduated bevel along the back half, from zero bevel at midpoint to 1" of bevel at the tail, along with aggressive V will accomplish in large measure what the flex tail is doing...more pressure on the rail, more tail rocker, tighter turns. 
I think this is a cool idea, but it seems a little too complicated.