
I just travelled with a borrowed 11'6 bag, but I think it belonged to one of those Starboard Start (Windsurfing) boards, as it was hell wide.
Once on the roof racks, it easily carried:
- 11'6 SUP
- Paddle
- 6'0 Surfboard (in it's own board bag)
- 138 Twintip (in it's own board bag)
- A Doona
- A Pillow
- A 7m Kite
.. and I reckon it easily could have carried my 12m & 9m kite without too much fuss.
Initially, the bag was a pain because of the flapping on the roof, but once we realised we could use all the space .. awesome!