Flex and Inflateables

[HanaSurf]

Is the flex felt on inflatables mainly happening from end to end?  In other words,if all else is same:drop stitch threads per sq.inch,thickness of material,psi,WIDTH,same quality materials,etc. would a 10'6 have less flex than a 12'6.

[Green Water Sports]

Everything being equal I would say yes. But that's not to say a 7ft board would be better 12ft board. Compromise is involved. I did an article looking at some of the factors relating to stiffness and how some companies try to minimise flex.

http://greenwatersports.com/3126/the-definitive-inflatable-sup-stiffness-guide

[TallDude]

Flex comes in all directions. Some Isups flex completely different then the next.
Here's a few ways I categorize them;
The twist, the taco, the trampoline, and the raft.
-The twist can happen on a wave. The back starts to turn as you lean, but the nose stays stuck the the wave face.
-The taco happens on longer inflatables. As you are in the power phase of your paddle stroke, the nose and tail lift out of the water.
-The trampoline is from higher pressure inflation. You feel like you are standing on a vibrating trampoline that doesn't stop.
-The raft is from cheaper, thin material Isups. They constantly bend and hug the water surface.

[HanaSurf]

I did forget one thing in original post.....toss the surfing out. Touring and distance fitness training. TallDude,I've experienced the trampoline effect and really didn't know what to call it but you definitely described it.    Julian,I don't know why the flex questions keeps going round in my mind, I know most makes of iSups make the 10's less than 6" thick and longer boards about 6".  Kinda wonder if with todays technology if 11' board 6" thick wouldn't be about optimal board for everything except surfing. Touring,Fitness,Mild River runs,etc.

[Green Water Sports]

The 10'6" Ride by Red Paddle Co is far and away the most popular board on my site. Like you mention, I think it's the right mix of length (10'6"), width(32"), thickness(4.75"), pressure(15-25PSI) for a good all round solid inflatable SUP.

http://greenwatersports.com/shop/red-paddle-co-10-6-ride